CN112394351A

CN112394351A - Aviation coaxial remote sensing device and method based on multiple sensors

Info

Publication number: CN112394351A
Application number: CN202011333303.7A
Authority: CN
Inventors: 潘洁; 朱金彪; 吴亮; 刘玉泉; 祁增营
Original assignee: Aerospace Information Research Institute of CAS
Current assignee: Aerospace Information Research Institute of CAS
Priority date: 2020-11-24
Filing date: 2020-11-24
Publication date: 2021-02-23

Abstract

The invention relates to an aviation coaxial remote sensing device and method based on multiple sensors, wherein a gyro stable platform is fixedly connected with an oblique flying remote sensing airplane; the remote sensing equipment is fixedly connected with the gyro stable platform; the GNSS antenna is fixedly connected with the top of the remote sensing airplane; the industrial personal computer is fixedly connected with the inclined flying remote sensing airplane floor; the antenna housing is fixedly connected with the oblique flying remote sensing airplane; the SAR antenna is fixedly connected with the oblique flying remote sensing airplane; the SAR antenna rotary table is fixedly connected with the oblique flying remote sensing airplane; the GNSS receiver is fixedly connected with the industrial personal computer; the GNSS receiver is connected with the industrial personal computer; the industrial personal computer is connected with the remote sensing equipment through a data line; the industrial personal computer is connected with the SAR antenna; the industrial personal computer is connected with the gyro stabilizing platform. By means of the oblique flying remote sensing airplane, an industrial personal computer is used for designing and displaying a flying route, and controlling a gyro stabilizing platform and an SAR antenna, so that different sensors can simultaneously acquire data aiming at the same earth surface area, coaxial remote sensing is realized, and the aerial remote sensing data acquisition efficiency and the sensor utilization rate are improved.

Description

Aviation coaxial remote sensing device and method based on multiple sensors

Technical Field

The invention relates to the technical field of remote sensing, in particular to an aviation coaxial remote sensing device and method based on multiple sensors.

Background

The aerial remote sensing is also called airborne remote sensing, which is a technology for carrying out remote sensing in the air by using a flying platform such as an airplane, an airship, a balloon and the like as a sensor carrier, and is a multifunctional comprehensive detection technology developed by aerial photography reconnaissance. The traditional aerial remote sensing system carries a sensor by utilizing an airplane to carry out ground observation, and along with the improvement of airplane performance, the improvement of sensor integration level and the requirement of high-efficiency remote sensing operation, the development trend of aerial remote sensing at the present stage is that one remote sensing airplane carries a plurality of different types of sensors to carry out ground observation in the air. The different types of sensors include multispectral cameras, hyperspectral imagers, infrared cameras, lidar, Synthetic Aperture Radars (SAR), and the like. The visual angles of different types of sensors for observing the ground are different, some sensors are downward-looking, namely vertical to the sea level, such as a multispectral camera, a hyperspectral imager, a thermal infrared camera, a laser radar and the like, and some sensors are side-looking, namely downward at a certain included angle with the sea level, such as an SAR; under the condition, when the sensors of different types simultaneously observe the ground, the coaxial remote sensing cannot be met, namely the ground observation aiming at the same ground surface area cannot be met, so that the remote sensing data acquired by the downward-looking sensor and the side-looking sensor are inconsistent; in addition, in order to ensure that all the sensors can acquire remote sensing data of the same ground surface area, the remote sensing aircraft needs to make up for differences caused by downward view and side view through multiple flight paths, and thus redundancy of the flight paths and reduction of flight efficiency are caused.

Disclosure of Invention

The invention aims to provide an aviation coaxial remote sensing device and method based on multiple sensors, which adopt a special flying method and control different devices through an industrial personal computer in the flying process, thereby realizing coaxial remote sensing of different types of sensors, namely realizing earth observation of the same earth surface area under the same space-time environment, reducing redundant flight, improving the working efficiency of aviation remote sensing and being capable of completing the aviation remote sensing task based on multiple sensors more quickly and conveniently.

In order to achieve the purpose, the invention has the following technical scheme:

the invention relates to an aviation coaxial remote sensing device based on multiple sensors, which comprises an oblique flying remote sensing airplane, a gyro stabilizing platform, remote sensing equipment, an industrial personal computer, an antenna cover, an SAR antenna turntable, a GNSS antenna and a GNSS receiver, wherein the gyro stabilizing platform is fixedly connected with an downward-looking remote sensing window of the oblique flying remote sensing airplane; the remote sensing equipment is fixedly connected with the gyro stable platform; the GNSS antenna is fixedly connected with the top of the oblique flying remote sensing airplane; the industrial personal computer is fixedly connected with the inclined flying remote sensing airplane floor; the antenna housing is fixedly connected with the belly and the machine side of the oblique flying remote sensing airplane; the SAR antenna is fixedly connected with the machine side of the oblique flying remote sensing aircraft and the SAR antenna rotary table respectively; the SAR antenna rotary table is connected with the belly of the oblique flying remote sensing airplane; the GNSS receiver is connected with the industrial personal computer; the GNSS antenna is connected with the GNSS receiver through a data line; the GNSS receiver is connected with the industrial personal computer through a data line; the industrial personal computer is connected with the remote sensing equipment through a data line; the industrial personal computer is connected with the SAR antenna through a data line; the industrial personal computer is connected with the gyro stabilizing platform through a data line;

the remote sensing plane flies obliquely, and the included angle between the transverse axis of the remote sensing plane and the sea level parallel plane is as follows: 15-30 degrees; the oblique flying remote sensing airplane comprises a structure mounting platform, a downward-looking optical window, optical glass and a photographic hatch door, wherein the structure mounting platform is positioned above the downward-looking optical window, the optical glass is positioned on the downward-looking optical window, and the photographic hatch door is positioned below the optical glass;

the remote sensing equipment comprises an SAR, a multispectral aerial camera, a hyperspectral aerial camera, an infrared aerial camera and a sensor of an airborne laser radar; the incident beam of the SAR antenna deviates along with the inclination of the oblique flying remote sensing airplane; when the inclined flying remote sensing airplane inclines, the gyro stabilizing platform is adjusted to be vertical to the sea level to carry out ground remote sensing observation downwards, and downward looking ground remote sensing observation is formed without being influenced by airplane angular motion; the gyro stable platform can be used for controlling the attitude of the remote sensing equipment;

the SAR carries out remote sensing observation to the ground through side view, namely, downward forming a certain included angle with a ground normal; an included angle between an incident beam emitted by the SAR antenna and a ground normal is 30-60 degrees; the multispectral aerial camera, the hyperspectral aerial camera, the infrared aerial camera and the airborne laser radar are used for performing remote sensing observation on the ground downwards through downward looking, namely vertical sea level;

wherein, the gyro stable platform is arranged on the structure mounting platform; remote sensing equipment of the multispectral aerial camera, the hyperspectral aerial camera, the infrared aerial camera and the airborne laser radar are all installed on the gyro stable platform, and the SAR and the gyro stable platform are installed in a separated mode;

the antenna housing is an airborne radar antenna housing, and the number of the antenna housings is three, wherein 1 antenna housing is arranged below the belly, and a left SAR antenna housing and a right SAR antenna housing are respectively arranged on two sides of the body;

wherein the three radomes are all mounted to the front half of the aircraft fuselage. The ventral radome is symmetrical relative to the plane of symmetry; the left and right SAR antenna covers are overlapped with the effective section of the ventral antenna cover in the front-back direction.

The SAR antenna rotary table is arranged on the belly of the oblique flying remote sensing airplane and used for controlling the orientation of the SAR antenna on the belly, so that the SAR antenna can incline leftwards or rightwards.

The SAR antenna is three in number, one is arranged on the SAR antenna rotary table, and the other two are respectively arranged on the left side and the right side of the oblique flying remote sensing airplane. The ventral SAR antenna is located inside the ventral radome, and the left and right SAR antennas are located inside the left and right SAR radomes respectively.

The three SAR antennas can acquire SAR data of P, L, C, X and other four wave bands, and the data acquired by the left and right SAR antennas are the same.

The GNSS antenna can receive GNSS signals and send the GNSS signals to the GNSS receiver, and the GNSS receiver processes the GNSS signals and then outputs GNSS data to the industrial personal computer.

The industrial personal computer comprises control equipment and display equipment, wherein the control equipment is used for controlling sensors such as a gyro stabilizing platform, an SAR antenna turntable, an SAR, a multispectral aerial camera, a hyperspectral aerial camera, an infrared aerial camera and an airborne laser radar; the display equipment is used for displaying a map, a flight route, an airplane flight track, airplane position information and the like.

The industrial personal computer can make a flight plan of the oblique flying remote sensing aircraft aiming at an operation area of aerial remote sensing, so that all remote sensing equipment on the oblique flying remote sensing aircraft can carry out ground remote sensing observation along a specified flight route, and the method comprises the following steps:

1) coordinate transformation

The coordinate transformation can improve the precision and efficiency of the system in the design of the flight path, because the data of different coordinate systems can be processed through the coordinate transformation. The coordinate systems commonly used at present include a WGS84 global coordinate system, a national 2000 coordinate system, a west safety 80 coordinate system, a beijing 54 coordinate system and a local coordinate system, and different coordinate system data sometimes need to be converted. Because the nodes in the flight survey area generally adopt the longitude and latitude coordinates of WGS84, the longitude and latitude coordinates are inconvenient for calculating the distance between the azimuth angle and the point line plane, and the plane coordinates are convenient for calculating, the conversion between the longitude and latitude coordinates and the plane rectangular coordinates is inevitable.

First, it is necessary to acquire geodetic coordinates (B) of a point using GPS₈₄ L₈₄ H₈₄)^TThen converted to space rectangular coordinates (X Y Z) by equation (1) according to the reference ellipsoid parameters of WGS84^TThen (X Y Z) is determined by formula (2) according to the reference ellipsoid parameters of Beijing 54 or Xian 80 or the local independent coordinate system^TConversion to geodetic coordinate form (B)₅₄ L₅₄ H₅₄)^TOr (B)₈₀ L₈₀ H₈₀)^TOr (B)_local L_local H_local)^TAnd finally, according to the central meridian, the elevation of the projection surface and the northbound east offset, the formula (3) is used for converting the (B) into the corresponding (B)₅₄ L₅₄)^TOr (B)₈₀ L₈₀)^TOr (B)_local L_local)^TThe projection is Gaussian coordinate (X)_g Y_g)^T；

Wherein the content of the first and second substances,

X＝C₀B+(C₂ cosB+C₄ cos³B+C₆cos⁵B+C₈cos⁷B)sin B (4)

t＝tanB (6)

l″＝L-L₀ (8)

wherein L, B is longitude and latitude coordinates before conversion; h is elevation

x and y are transformed Gaussian coordinates;

a is the major radius of the ellipsoid, and e is the first eccentricity of the ellipsoid;

L₀central meridian longitude of the projection zone;

C₀、C₂、C₄、C₆、C₈is a constant value related only to the ellipsoid parameter;

coordinate transformation is used in the design of the flight route, and compared with the conventional manual route design, the efficiency of the design of the flight band can be improved; although the current manual calculation is relatively perfect and stable, if the number of the navigation films is too large, the calculation intensity is higher, and meanwhile, the electronic map with higher precision cannot be utilized in the manual navigation tape calculation, so that the route design utilizing coordinate transformation has obvious advantages, and the range of the survey area is more definite; the application of coordinate transformation improves the precision and efficiency of the flight band design and also improves the capability of the system for processing various coordinate system data.

2) Automatic judgment of air route

The buffer area analysis introduced into the geographic information system in the multi-sensor-based aerial remote sensing flight management system can simplify the calculated amount and improve the flight quality in the air to a certain extent. The buffer area is a polygon with a certain width range around the entities such as points, lines, surfaces and the like, and the aviation remote sensing flight management system based on the multiple sensors can generate a judgment buffer area with a specific shape according to the flight mission. When the system automatically shoots a certain preset area, the relative position between the airplane and the measuring area and between the airplane and the flight route needs to be judged, but due to the complexity of the actual situation (a pilot can adjust to a proper angle according to the airflow state to carry out plane flight), many judgment conditions are needed for correctly judging the relative position of the airplane, and the calculation amount needed by real-time calculation is large. In order to ensure the smooth operation of the system, the system needs to generate some buffer areas in advance to judge the relative position, so that the relative position of the oblique flying remote sensing aircraft and the air route can be determined only by judging whether the oblique flying remote sensing aircraft is in the buffer areas, and the calculated amount is greatly reduced. When the oblique flying remote sensing aircraft enters a buffer zone and simultaneously meets the flight altitude limiting condition to enter a flight line, the oblique flying remote sensing aircraft can be considered as effective entry; when the oblique flying remote sensing aircraft shoots after entering the air route, if the oblique flying remote sensing aircraft flies away from the preset air route and exceeds the air belt buffer area, the system gives a prompt and correspondingly automatically stops shooting of the aerial sensor, so that the flight waste which does not accord with the air route design is avoided. Therefore, a buffer zone is established to a certain extent, and the quality of the flight path can be ensured.

Currently, with the improvement of the accuracy of the GNSS device, the relative position of the aircraft and the predetermined route can be determined through the feedback information of the GNSS device, so as to automatically judge and execute the relevant operation on the aviation sensor in time.

3) Course position calculation

Firstly, rotating a coordinate system according to the arrangement direction of the air route, and enabling an X' axis of the rotated coordinate system to be parallel to the direction of the air route; therefore, the position of the route is calculated only by requiring the course central line and the number of routes of the survey area, and then other routes are symmetrically laid to two sides in parallel with the course central line of the survey area; the ordinate of the course center line is:

Y′＝(Y′_max+Y′_min)/2 (9)

of formula (II) to (III)'_max、Y′_minRespectively is the maximum value and the minimum value of the polygon circumscribed rectangle ordinate under the X 'Y' coordinate system;

according to the requirements of national standard topographic map aerial photogrammetry internal work specifications, the sidewise coverage exceeds the boundary line of the photographic area and is generally not less than 50% of the image frame, and at least not less than 30% of the image frame; is provided with L_YFor the lateral coverage width of the image frame on the ground, the minimum total coverage width is designed as follows:

W_min＝Y′_max-Y′_min+2L_Y (10)

and setting the number of the routes in the survey area as n, wherein the total coverage width of all routes is as follows:

W＝((1-S)(n-1)+1)×L_Y (11)

wherein S is the lateral overlapping rate; from equation (11), n ═ 1+ (W-L) can be determined_Y)/(L_Y-SL_Y) (ii) a n must be an integer, and the coverage width is guaranteed, n is rounded and added by 1, that is

n＝[1+(W-L_Y)/(L_Y-SL_Y)]+1 (12)

In the above formula, the parenthesis indicates rounding, and W is W_minSubstituting, namely calculating the total number of routes meeting the requirements;

whether n is odd or even, all the routes are symmetrically distributed along the two sides in parallel with the central line, and a calculation formula of the vertical coordinate of each route can be deduced according to photogrammetry related knowledge by combining a schematic diagram:

Y′_m＝(Y′_max+Y′_min)/2+(m-(n+1)/2)(1-S)×L_Y (13)

in the formula, m is the number from the air route to the lower part and is more than or equal to 1 and less than or equal to n;

4) calculation of coordinates of exposure points

For flat areas, the length of the base line of an aerial photogrammetry area is basically unchanged; taking central point coordinate X ' in polygon X ' direction of measured area '₀＝(X′_max+X′_min) (iii)/2, wherein, X'_maxAnd X'_minThe maximum value and the minimum value of the abscissa of the circumscribed rectangle of the polygon under the X 'Y' coordinate system;

the coordinates of the exposure point on a certain flight path are calculated, the intersection point of the flight path and the polygon of the survey area can be calculated firstly, and then the center point (X'₀，Y′_m) As a starting point, respectively extending integral multiples of a shooting baseline leftwards and rightwards in an intersection point abscissa maximum and minimum interval to obtain a series of intersection points, namely exposure points;

X′_k＝X′₀±B_k×k(k＝0，1，2...) (14)

in the formula B_kIs a base line long;

if the route line has no intersection point or only one intersection point with the polygon, namely the route line is arranged outside the polygon of the survey area or intersects at a node at the top or the bottom of the polygon, then the center point (X'₀，Y′_m) As a starting point, in (X'_min X′_max) Respectively extending integral multiples of a shooting baseline to the left and the right in the interval to obtain a series of points, sequentially taking the points as exposure centers, calculating a coverage area of the photo on the ground, and if the area is overlapped with a polygon of a measuring area, taking the point as an exposure point;

meanwhile, the requirement of aerial photography specifications is considered, course coverage exceeds a certain range of a shot region boundary line, and two base lines are added, so that a corresponding number of exposure points are added outside the boundary;

5) DEM-based air route design

The air route design based on the DEM is to combine the DEM and the GIS, fully consider the important role of topographic factors in the design of the aerial photography air route, use the DEM data as the basis, use the GIS as the technical support, use grids and vector diagrams as the visual background, solve the problems of zoning division of the survey area, parameter calculation, air route laying and the like in the current actual design through mathematical operation and condition judgment, and realize the design of the aerial photography air route with high precision and high quality;

according to aerial photogrammetry specifications, a certain overlap is required between adjacent aerial photographic films so as to cover a measuring area and facilitate later three-dimensional mapping; the overlap ratio comprises a course overlap ratio and a sidewise overlap ratio, and the formula is as follows:

wherein P, Q is the overlapping part of the adjacent images in the course and side direction, x and y are the overlapping parts of the adjacent images in the course and side direction, respectively_x、l_yRespectively image width and length;

the topographic relief directly influences the course and the lateral overlapping rate, and the influence can be analyzed by the formula (15); in addition, the topographic relief will cause a series of changes such as the shooting baseline and the shooting interval;

wherein H is the height difference relative to the average elevation datum level, H_{Taking a photograph}For the relative navigational height of the aerial photography, P, Q is the actual course and the lateral overlapping rate, P 'and Q' are the planned course and the lateral overlapping rate, the DEM can reflect the terrain fluctuation most effectively, the h value of the required point can be obtained very quickly, and the computer rapid operation is provided;

the altitude values of the flight routes and the image principal points can be obtained from the digital altitude model through a computer, the variation of course lateral overlapping rate can be calculated according to the formula (16), and then the positions of the adjacent image principal points and the positions of the adjacent routes can be calculated;

for the topographic relief area, the influence of DEM needs to be considered, firstly, the actual overlapping rate of the photo on the average plane is calculated according to the planned course overlapping rate of the photo, the length B of a photographing base line is calculated, and then the position O of the next image principal point is calculated according to the position of the image principal point and the course overlapping rate_i(ii) a Similarly, the interval D of the shooting route is calculated according to the lateral overlapping rate, and finally the position O of each image principal point on other routes is obtained according to the intervals D and B of the shooting routes_j；

In the formula: b_x、B_xThe camera baseline length on the picture and on the field;

d_x、D_ylane spacing widths on the picture and on the field;

L_x、L_ythe length and width of the photographic image;

p_x、q_ythe course and the lateral overlapping rate;

m_{navigation device}And is an aerial photography scale denominator.

The industrial personal computer can display a map, a flight route, a flight track of the oblique flying remote sensing aircraft and position information of the oblique flying remote sensing aircraft in real time, and on-board operators can control the time of turning on and off the remote sensing equipment according to the displayed information, so that all the remote sensing equipment can synchronously carry out remote sensing observation on the ground. The method comprises the following steps:

1) loading and displaying an electronic map of an administrative division;

2) loading a flight plan file, and displaying a flight route on an electronic map;

3) acquiring longitude and latitude coordinates and time information of the oblique flying remote sensing airplane through a GNSS receiver, and converting the longitude and latitude coordinates into plane rectangular coordinates corresponding to an electronic map to display the position of the oblique flying remote sensing airplane on the electronic map;

4) displaying a symbol of the remote sensing plane obliquely flying, namely acquiring a position point of the current remote sensing plane obliquely flying; calling a symbol library; defining symbol objects and setting attributes; drawing a symbol object;

5) dynamically displaying the flight track of the oblique flying remote sensing airplane, namely forming line segments by coordinate points arranged according to a time sequence of the oblique flying remote sensing airplane, and drawing the line segments representing the movement track of the airplane through a DrawShape function of a map control;

6) the on-board operator determines the time of the approach path of the oblique flying remote sensing aircraft according to the aircraft position, the flight path and the flight track of the oblique flying remote sensing aircraft, and uses an industrial personal computer to start remote sensing equipment; and determining the time when the oblique flying remote sensing aircraft leaves the air route, and closing the remote sensing equipment by using an industrial personal computer.

The SAR observation mode is that remote ground sensing observation is carried out in a side view mode, the included angle between an incident beam of an antenna and a ground normal is set to be 30-60 degrees, the sampling angle range of the incident beam of the left SAR antenna is-30-60 degrees, and the sampling angle range of the incident beam of the right SAR antenna is set to be 30-60 degrees; the observation modes of the multispectral aerial camera, the hyperspectral aerial camera, the infrared aerial camera and the airborne laser radar remote sensing equipment on the gyro stable platform are downward looking, and the range of an included angle between an incident beam of a sensor head and a ground normal is set to be-30 degrees, and the sampling angle range of the incident beam is-30 degrees; therefore, the earth observation ranges of the side-looking remote sensing equipment and the lower-looking remote sensing equipment under the same condition are different, and in order to ensure that the SAR is consistent with the earth observation ranges of other remote sensing equipment, the following method steps are adopted:

1) open top stabilized platform control software in the industrial computer, click "communication setting", set up the angle parameter, wherein, the scope of roll angle is established as: -30 ° - +30 °; the range of pitch angles is set as: -8 ° - +6 °; the range of the spin deflection angle is set as follows: -30 ° - +30 °;

2) determining the side overlapping rate in 50-75% according to the set condition of the mission plan, making a flight plan according to the requirement, and generating a flight route; displaying a map, a flight route, an airplane flight track and airplane position information in an industrial personal computer according to the requirement;

3) when a first flight path 1 flying by the aircraft is positioned at the west-most side or the south-most side of the operation area, informing a pilot to enable the oblique flying remote sensing aircraft to tilt downwards by 15-30 degrees leftwards around the longitudinal axis of the aircraft to form the oblique flying remote sensing aircraft with a tilt angle of 15-30 degrees leftwards, and keeping the state to fly along the first flight path 1, wherein at the moment, a gyro stabilizing platform can automatically correct a roll angle, so that remote sensing equipment on the gyro stabilizing platform keeps a downward-looking earth observation state;

4) opening SAR antenna turntable control software in an industrial personal computer, setting the turntable to incline leftwards and downwards, and setting the sampling angle range of an incident beam of an SAR antenna on the turntable to be-30 degrees to-60 degrees; at the moment, the sampling angle ranges of the incident beams of the ventral SAR antenna and the left SAR antenna are-30-0 degrees;

5) when the oblique flying remote sensing airplane displayed on the industrial personal computer enters a flight route, all the remote sensing equipment is started, and when the oblique flying remote sensing airplane keeps the state and flies out of the flight route, all the remote sensing equipment is closed, and the parallel flight of the oblique flying remote sensing airplane is recovered;

6) turning the oblique flying remote sensing aircraft, preparing to fly a second flight path 5, informing a pilot to tilt the oblique flying remote sensing aircraft downwards by 30 degrees towards the right around the longitudinal axis of the aircraft, forming the oblique flying remote sensing aircraft with a tilt angle of 15-30 degrees towards the right, and keeping the state to fly along the second flight path 5, wherein at the moment, the gyro stabilizing platform can automatically correct a roll angle, so that the remote sensing equipment on the gyro stabilizing platform keeps a downward-looking earth observation state;

7) and starting SAR antenna turntable control software in an industrial personal computer, setting the turntable to incline downwards to the right, and setting the sampling angle range of the SAR antenna incident beam on the turntable to be 30-60 degrees. At the moment, the sampling angle ranges of the incident beams of the ventral SAR antenna and the right SAR antenna are both 0-30 degrees;

8) when the plane displayed on the industrial personal computer enters a flight route, all the remote sensing devices are turned on, and when the oblique flying remote sensing plane flies out of the route in the state, all the remote sensing devices are turned off, and the parallel flight of the oblique flying remote sensing plane is recovered;

9) repeating the step 3) and the step 8) until all air routes in the operation area are flown, and ending the flight task;

10) when the first route 1 flying by the aircraft is positioned at the most east or the most north of the operation area, informing a pilot to tilt the remote sensing aircraft obliquely downwards by 15-30 degrees around the longitudinal axis of the aircraft to form the remote sensing aircraft obliquely downwards tilted by 15-30 degrees, and keeping the state to fly along the first route 1, wherein the gyro stabilizing platform can automatically correct the roll angle at the moment, so that the remote sensing equipment on the gyro stabilizing platform keeps a downward-looking earth observation state;

11) opening SAR antenna turntable control software in an industrial personal computer, setting the turntable to incline downwards to the right, and setting the sampling angle range of an incident beam of an SAR antenna on the turntable to be 30-60 degrees; at the moment, the sampling angle ranges of the incident beams of the ventral SAR antenna and the right SAR antenna are both 0-30 degrees;

12) when the plane displayed on the industrial personal computer enters a flight route, all the remote sensing devices are turned on, and when the oblique flying remote sensing plane flies out of the route in the state, all the remote sensing devices are turned off, and the parallel flight of the oblique flying remote sensing plane is recovered;

13) turning the oblique flying remote sensing aircraft, preparing to fly a second route 5, informing a pilot to tilt the oblique flying remote sensing aircraft leftwards and downwards by 30 degrees around the longitudinal axis of the aircraft to form the oblique flying remote sensing aircraft with a tilt angle of 15-30 degrees, and keeping the state to fly along the second route 5, wherein at the moment, the gyro stabilizing platform can automatically correct a roll angle, so that the remote sensing equipment on the gyro stabilizing platform keeps a downward-looking earth observation state;

14) and opening SAR antenna turntable control software in an industrial personal computer, setting the turntable to incline leftwards and downwards, and setting the sampling angle range of the SAR antenna incident beam on the turntable to be-30 degrees to-60 degrees. At the moment, the sampling angle ranges of the incident beams of the ventral SAR antenna and the left SAR antenna are-30-0 degrees;

15) when the plane displayed on the industrial personal computer enters a flight route, all the remote sensing devices are turned on, and when the oblique flying remote sensing plane flies out of the route in the state, all the remote sensing devices are turned off, and the parallel flight of the oblique flying remote sensing plane is recovered;

16) and repeating the steps 10) to 15) until all the air routes in the operation area are flown, and finishing the flight task.

The included angle between the incident beam of the SAR antenna and the ground normal can be set to be other ranges, not limited to 30-60 degrees, or 20-50 degrees or 25-55 degrees, and the length of the range interval is less than 40 degrees; the remote sensing device for side view is not limited to SAR, and other remote sensing devices for side view such as oblique photography aerial camera are also suitable.

Wherein the distance resolution of the remote sensing equipment SAR is as follows:

wherein tau is the pulse width of the SAR, C is the light speed, and theta is the side view angle of the SAR antenna incident beam;

because the oblique flying remote sensing airplane flies obliquely, theta is changed from +/-45 degrees to +/-15 degrees, and the delta R is increased, namely the distance resolution is reduced; in order to ensure that the distance resolution is not reduced, the pulse width and amplitude are modulated by using linear frequency modulation, and tau is reduced, so as to ensure that the distance resolution is not reduced, and the method comprises the following steps:

modulating the harmonic waves by linear frequency to generate a linear frequency modulation pulse, then transmitting the pulse, after receiving the pulse, enabling the pulse to pass through a matched filter with opposite frequency characteristics in frequency and time relation to the pulse during transmission, firstly enabling the delay of a received low-frequency echo in the filter to be larger than that of a received high-frequency echo, and further extracting a received pulse signal in a mode of reducing the pulse width and increasing the pulse amplitude;

within the pulse width, the instantaneous frequency is linearly changed by f_minChange to f_maxFrequency modulation bandwidth Δ f ═ f_max-f_min(ii) a The envelope of the wave function generated by the echo through the matched filter (the envelope is a graph formed by interweaving a plurality of elliptic curves, the appearance looks like a bag, and the envelope has own unique meanings in mathematics, signal processing, literature, economy and traditional Chinese medicine) is

The main lobe of the waveform is larger than the side lobe, and the half-power width is

I.e. the pulse width tau after compression₀Whereby the pulse width is compressed to the original

The larger the Δ f is, the smaller the compressed pulse width is, the smaller the Δ R is, and the higher the distance resolution is;

wherein f is_minIs the minimum instantaneous frequency, f_maxIs the maximum instantaneous frequency; sinc is a function of the sine,

when the sampling angle range of the incident beam of the left SAR antenna in the step 4) is-30-0 degrees, the sampling angle range of the incident beam of the corresponding right SAR antenna is 60-90 degrees, and the lateral viewing angle of the incident beam of the right SAR antenna is 75 degrees; according to the trigonometric function principle, when the sampling angle is changed from 30 degrees to 60 degrees, the corresponding ground coverage range is changed from H tan30 degrees to H tan60 degrees;

wherein H is the relative navigational height of the airplane,

tan 90 degrees is infinity, and the ground coverage can be calculated to be 3 times of the original coverage; if the coverage range corresponding to the sampling angle of-30 degrees is the nth route 30 in the flight plan, the coverage range corresponding to the sampling angle of 60-90 degrees is the (3+ n) -nth route 30 in the flight plan, which is equivalent to acquiring the data corresponding to the routes in advance; meanwhile, the side view angle of the incident beam of the right SAR antenna is changed from 45 degrees to 75 degrees, the side view angle is increased, and according to the formula (19), the distance resolution delta R of the (3+ n) -nth route 30 corresponding to the remote sensing data is reduced, namely the distance resolution is improved. (according to the previous step, SAR data is obtained by half less than other remote sensing equipmentLines, which can make up for fewer lines, can fly some more range than other remote sensing devices, and ensures range resolution). Similarly, step 7), step 11) and step 14) all have the features of step 4).

According to the previous method, if only the SAR antenna on the side of the airplane inclining downwards is considered, when the remote sensing airplane flies to the first flight path 1 obliquely, the SAR acquires ground data corresponding to an included angle of-30 degrees to 0 degrees between an incident beam of the SAR antenna and a ground normal, other remote sensing equipment acquires ground data corresponding to an included angle of-30 degrees to +30 degrees between a longitudinal axis of a sensing head of other remote sensing equipment and the ground normal, and the SAR acquires the ground data corresponding to 0 degrees to 30 degrees, namely the data of a half flight path less than other remote sensing equipment; because the lateral overlapping rate between the routes is 50-75%, when the aircraft flies to the second route 5, the SAR acquires ground data corresponding to 0-30 degrees, and the overlapping rate of the data and the SAR acquired data of the previous route is 0-25%; the data obtained by other remote sensing equipment is ground data corresponding to an included angle of-30 degrees to +30 degrees between the longitudinal axis of the sensing head of other remote sensing equipment and the ground normal, the data is overlapped with the data obtained by other remote sensing equipment of the previous route by 50-75 percent, and SAR is less than that of other remote sensing equipment to obtain the data of a half route; therefore, after all the routes are flown out, the SAR always acquires data of half routes less than other remote sensing equipment. The data acquired by the SAR antenna on the side inclined upwards can be made up for the missing data of the half route in advance; due to the fact that the side view angle of the SAR antenna on the left side or the right side is increased due to inclined flight, the obtained data is far more than a half route, and according to the formula (19), the distance resolution ratio is higher than that of the original distance resolution ratio; other remote sensing devices refer to, but are not limited to, multispectral aerial cameras, hyperspectral aerial cameras, infrared aerial cameras, and airborne lidar.

Due to the adoption of the technical scheme, the invention has the advantages that:

1. the multifunctional remote sensing system has the advantages that the multifunctional remote sensing system is multifunctional, various remote sensing data can be obtained through one-time flight, and an industrial mode that the traditional aviation remote sensing system is used for one aircraft is replaced;

2. the coaxial remote sensing under the background of space-time consistency is realized, redundant flight is avoided, the flight route is reduced, the flight time and the oil consumption of the airplane are reduced, the intensity of aerial work and the difficulty of post data processing are reduced, and the cost and the time are saved;

3. the technical level of the aerial remote sensing industry is improved.

Drawings

FIG. 1 is a schematic illustration of the flight of the present invention;

FIG. 2 is a schematic diagram of the overlapping portions of the SAR and other remote sensing devices observed over the ground formed after the first to third flight paths 9 of the present invention;

FIG. 3 is a schematic view of the apparatus of the present invention;

FIG. 4 is a schematic diagram of an observation angle of parallel flight to the ground of a slant-flight remote sensing aircraft according to the invention, including an SAR side view and a downward view of other remote sensing equipment;

FIG. 5 is a schematic diagram of an observation angle of an oblique flying remote sensing airplane obliquely flying to the ground from the side view of the SAR and the downward view of other remote sensing equipment;

FIG. 6 is a schematic view of a radome installation of the present invention;

FIG. 7 is a schematic view in the direction A-A of FIG. 6;

FIG. 8 is a flow chart of the onboard operation of the present invention.

In the figure:

1. a first route; 2. a first route SAR and other remote sensing equipment observe an overlapping region to the ground; 3. other remote sensing equipment of the first route observes the area to the ground; 4. a first flight path inclined flight remote sensing airplane; 5. a second route; 6. a second route SAR and other remote sensing equipment observe an overlapping region to the ground; 7. other remote sensing equipment of the second route observes the area to the ground; 8. the remote sensing aircraft flies obliquely along a second route; 9. a third route; 10. the third route SAR and other remote sensing equipment observe the overlapping area to the ground; 11. a third flight line inclined flight remote sensing airplane; 12. the other remote sensing equipment of the third route observes the area to the ground; 13. a slant flying remote sensing airplane; 14. a display; 15. an industrial personal computer; 16. a belly antenna; 17. a left SAR radome; 18. a right SAR radome; 19. 20, 21: a remote sensing device; 22. a left side view SAR earth observation area; 25. a right-side view SAR earth observation area; 26. observing an overlapping area to the ground by the SAR and the remote sensing equipment; 27. a right SAR to ground viewing area; 28. the remote sensing equipment observes the area to the ground; 29. a no-data area; 30. the nth route; 31. the (n + 1) th route; 32. the (n + 2) th route; 33. the (n + 3) th route; 36. a left side antenna; 37. a left antenna mounting plate; 38. a ventral radome; 39. an abdomen antenna mounting plate; 40. an SAR antenna turntable; 41. a belly antenna; 43. a right antenna mounting plate; 44. a right side antenna; 45. buckling; 46. fixing the rod; 47. identifying an angle; 48. and a bearing.

Detailed Description

The following examples are intended to illustrate the invention but are not intended to limit the scope of the invention.

Referring to the attached drawings 1-8, the aviation coaxial remote sensing method and device based on the multiple sensors comprises an oblique flying remote sensing airplane 13, a gyro stabilized platform, a remote sensing device 19, an industrial personal computer 15, antenna covers 17, 18 and 38, SAR antennas, GNSS antennas and GNSS receivers. The gyro stable platform is fixedly connected with a downward-looking remote sensing window of the oblique flying remote sensing airplane 13; the remote sensing equipment 19 is fixedly connected with the gyro stable platform; the GNSS antenna is fixedly connected with the top of the oblique flying remote sensing airplane 13; the industrial personal computer 15 is fixedly connected with the floor of the inclined flight remote sensing airplane 13; the antenna covers 17, 18 and 38 are fixedly connected with the oblique flying remote sensing airplane 13; the SAR antenna is fixedly connected with the oblique flying remote sensing airplane 13; the SAR antenna rotary table 40 is fixedly connected with the oblique flying remote sensing airplane 13; the GNSS receiver is fixedly connected with the industrial personal computer 15; the GNSS antenna is connected with the GNSS receiver through a data line; the GNSS receiver is connected with the industrial personal computer 15 through a data line; the industrial personal computer 15 is connected with the remote sensing equipment 19 through a data line; the industrial personal computer 15 is connected with the SAR antenna through a data line; the industrial personal computer 15 is connected with the gyro stabilizing platform through a data line.

The oblique flying remote sensing airplane 13 comprises a structure mounting platform, an downward-looking optical window, optical glass and a camera door. The structure mounting platform is located above the downward-looking optical window, the optical glass is located on the downward-looking optical window, and the camera door is located below the optical glass.

The gyro-stabilized platform can enable the remote sensing equipment 19 to conduct remote sensing observation on the ground vertically below the sea level without being influenced by the angular motion of the airplane; the gyrostabiliser platform can be used to control the attitude of the remote sensing device 19;

the remote sensing device 19 comprises sensors such as an SAR, a multispectral aerial camera, a hyperspectral aerial camera, an infrared aerial camera and an airborne laser radar.

The SAR carries out remote sensing observation to the ground through side view, namely, downward forming a certain included angle with a ground normal; the multispectral aerial camera, the hyperspectral aerial camera, the infrared aerial camera and the airborne laser radar are used for remotely sensing and observing the ground by looking down, namely looking down perpendicular to the sea level.

Wherein, the gyro stable platform is arranged on the structure mounting platform; remote sensing equipment 19 such as multispectral aerial camera, hyperspectral aerial camera, infrared aerial camera and airborne laser radar are all installed on the gyro stable platform, and SAR is not related to the gyro stable platform.

The radome is an airborne radar radome and comprises a left SAR radome 17, a right SAR radome 18 and an abdomen radome 38, wherein the abdomen radome 38 is arranged below the abdomen, and the left SAR radome 17 and the right SAR radome 18 are respectively arranged on two sides of the body.

The SAR antennas comprise SAR antennas at the belly of the oblique flying remote sensing airplane 13 and SAR antennas at the left side and the right side of the oblique flying remote sensing airplane;

the SAR antenna of the belly of the oblique flying remote sensing airplane 13 comprises a belly antenna 16, an SAR antenna rotary table 40, a belly antenna mounting plate 39 and a belly antenna cover 38, wherein the belly antenna mounting plate 39 is mounted on the belly of the oblique flying remote sensing airplane 13, the SAR antenna rotary table 40 is mounted on the belly antenna mounting plate 39, an belly antenna 41 is mounted on the SAR antenna rotary table 40, the belly antenna cover 38 is mounted on the belly of the oblique flying remote sensing airplane 13 and wraps the belly antenna 16 in the belly antenna cover 38, and the SAR antenna rotary table 40 is used for controlling the azimuth of the belly antenna 16 so as to enable the belly antenna 16 to incline leftwards or rightwards;

the SAR antenna on the left and right sides of the oblique flying remote sensing airplane is symmetrically installed on the left and right sides of the abdomen of the oblique flying remote sensing airplane 13, the left SAR antenna comprises a left antenna 36 and a left antenna installation plate 37, a left SAR radome 17 is installed on the abdomen of the oblique flying remote sensing airplane 13, the left antenna 36 is installed on the left antenna installation plate 37, the left SAR radome 17 is installed on the left side of the abdomen of the oblique flying remote sensing airplane 13 and wraps the left antenna 36 in the left SAR radome 17, the right SAR antenna comprises a right antenna 44 and a right antenna installation plate 43, the right SAR radome 18 is installed, the right antenna 44 installation plate is installed on the abdomen of the oblique flying remote sensing airplane 13, the right antenna 44 is installed on the right antenna installation plate 43, the right SAR radome 18 is installed on the right side of the abdomen of the oblique flying remote sensing airplane 13, and the right antenna 44 is wrapped inside the right SAR radome 18;

wherein, SAR antenna revolving stage 40 includes revolving stage post, bearing 48, dead lever 46, buckle 45, angle sign 47, the revolving stage post passes through bearing 48 with ventral antenna mounting panel 39 is connected, ventral antenna 16 dress is in can rotate on the revolving stage post, revolving stage post upper surface is equipped with angle sign 47, dead lever 46 one end is fixed revolving stage post upper surface, the dead lever 46 other end can with buckle 45 on the ventral antenna mounting panel 39 is fixed, makes ventral antenna 16 pass through on the revolving stage post upper surface angle sign 47 has set for and has fixed after the observation angle to ground.

Wherein, the left SAR antenna housing 17, the right SAR antenna housing 18 and the ventral antenna housing 38 are all installed on the front half section of the airplane body. Wherein the ventral radome 38 is symmetrical with respect to the plane of symmetry of the aircraft; the left and

right SAR radomes

17 and 18 overlap an effective section of the ventral radome 38 in the front-rear direction.

The SAR antenna rotary table 40 is arranged on the belly of the oblique flying remote sensing airplane 13 and used for controlling the orientation of the SAR antenna on the belly, so that the SAR antenna can incline leftwards or rightwards.

The SAR antenna rotary table 40 is provided with three SAR antennas, one SAR antenna is arranged on the SAR antenna rotary table 40, and the other two SAR antennas are respectively arranged on the left side and the right side of the oblique flying remote sensing airplane 13. The ventral SAR antenna is located inside the ventral radome 38, and the left and right SAR antennas are located inside the left SAR radome 17 and the right SAR radome 18, respectively.

The GNSS antenna can receive GNSS signals and send the GNSS signals to the GNSS receiver, and the GNSS receiver processes the GNSS signals and outputs GNSS data to the industrial personal computer 15.

The industrial personal computer 15 comprises control equipment and display equipment, wherein the control equipment is used for controlling sensors such as a gyro stabilizing platform, an SAR antenna turntable 40, an SAR, a multispectral aerial camera, a hyperspectral aerial camera, an infrared aerial camera and an airborne laser radar; the display equipment is used for displaying a map, a flight route, an airplane flight track, airplane position information and the like.

The industrial personal computer 15 can make a flight plan for an operation area of aerial remote sensing, so that all remote sensing equipment 19 can carry out ground remote sensing observation along an appointed flight route, and the method comprises the following steps:

1) coordinate transformation

First, it is necessary to acquire geodetic coordinates (B) of a point using GPS₈₄ L₈₄ H₈₄)^TThen converted to space rectangular coordinates (X Y Z) by equation (1) according to the reference ellipsoid parameters of WGS84^TThen (X Y Z) is determined by formula (2) according to the reference ellipsoid parameters of Beijing 54 or Xian 80 or the local independent coordinate system^TConversion to geodetic coordinate form (B)₅₄ L₅₄ H₅₄)^TOr (B)₈₀ L₈₀ H₈₀)^TOr (B)_local L_local H_local)^TAnd finally, according to the central meridian, the elevation of the projection surface and the northbound east offset, the formula (3) is used for converting the (B) into the corresponding (B)₅₄L₅₄)^TOr (B)₈₀ L₈₀)^TOr (B)_local L_local)^TThe projection is Gaussian coordinate (X)_g Y_g)^T。

Wherein the content of the first and second substances,

X＝C₀B+(C₂ cos B+C₄ cos³B+C₆ cos⁵B+C₈ cos⁷B)sin B (4)

t＝tan B (6)

l″＝L-L₀ (8)

wherein L, B is longitude and latitude coordinates before conversion;

x and y are transformed Gaussian coordinates;

L₀central meridian longitude of the projection zone;

C₀、C₂、C₄、C₆、C₈is a constant value related only to the ellipsoid parameter.

The use of coordinate transformations in flight path design may improve the efficiency of the flight strip design relative to conventional manual path designs. Although the manual calculation is relatively perfect and stable at present, if the number of the navigation films is too large, the calculation intensity is high, and meanwhile, the electronic map with high precision cannot be utilized in the manual navigation tape calculation, so that the route design utilizing coordinate transformation has obvious advantages, and the range of the survey area is more definite. The application of coordinate transformation improves the precision and efficiency of the flight band design and also improves the capability of the system for processing various coordinate system data.

2) Automatic judgment of air route

The buffer area analysis introduced into the geographic information system in the multi-sensor-based aerial remote sensing flight management system can simplify the calculated amount and improve the flight quality in the air to a certain extent. The buffer area is a polygon with a certain width range around the entities such as points, lines, surfaces and the like, and the aviation remote sensing flight management system based on the multiple sensors can generate a judgment buffer area with a specific shape according to the flight mission. When the system automatically shoots a certain preset area, the relative position between the airplane and the measuring area and between the airplane and the flight route needs to be judged, but due to the complexity of the actual situation (a pilot can adjust to a proper angle according to the airflow state to carry out plane flight), many judgment conditions are needed for correctly judging the relative position of the airplane, and the calculation amount needed by real-time calculation is large. In order to ensure the smooth operation of the system, the system needs to generate some buffer areas in advance to judge the relative position, so that the relative position of the airplane and the air route can be determined only by judging whether the airplane is in the buffer areas, and the calculation amount is greatly reduced. When the aerial camera enters the buffer zone and simultaneously meets the flight altitude limiting condition to enter the air route, the aerial camera can be considered as effective entry. When the aircraft shoots after entering the air route, if the aircraft flies away from the preset air route and exceeds the air belt buffer area, the system gives a prompt and correspondingly automatically stops shooting of the aerial sensor, so that the waste of flight which does not accord with the design of the air route is avoided. Therefore, a buffer zone is established to a certain extent, and the quality of the flight path can be ensured.

3) Course position calculation

Firstly, rotating a coordinate system according to the arrangement direction of the air route, and enabling an X' axis of the rotated coordinate system to be parallel to the direction of the air route; therefore, the position of the route is calculated only by requiring the course central line and the number of routes of the survey area, and then other routes are symmetrically laid to two sides in parallel with the course central line of the survey area. The ordinate of the course center line is:

Y′＝(Y′_max+Y′_min)/2 (9)

of formula (II) to (III)'_max、Y′_minRespectively is the maximum value and the minimum value of the ordinate of the polygon circumscribed rectangle under the X 'Y' coordinate system.

According to the requirements of national standard topographic map aerial photogrammetry internal work specifications, the sidewise coverage exceeds the boundary line of the shot region, and is generally not less than 50% of the image frame, and at least not less than 30% of the image frame. Is provided with L_YFor the lateral coverage width of the image frame on the ground, the minimum total coverage width is designed as follows:

W_min＝Y′_max-Y′_min+2L_Y (10)

W＝((1-S)(n-1)+1)×L_Y (11)

wherein S is the side lap ratio. From equation (11), n ═ 1+ (W-L) can be determined_Y)/(L_Y-SL_Y). n must be an integer, and the coverage width is guaranteed, n is rounded and added by 1, that is

n＝[1+(W-L_Y)/(L_Y-SL_Y)]+1 (12)

(in the above formula, parentheses indicate rounding), and W is represented by W_minSubstitution, i.e.And calculating the total number of routes meeting the requirements.

Y′_m＝(Y′_max+Y′_min)/2+(m-(n+1)/2)(1-S)×L_Y (13)

in the formula, m is the number from the air route to the lower part, and m is more than or equal to 1 and less than or equal to n.

4) Calculation of coordinates of exposure points

For flat areas, the baseline length of the aerial photogrammetry region is substantially constant. Taking central point coordinate X ' in polygon X ' direction of measured area '₀＝(X′_max+X′_min) (iii)/2, wherein, X'_maxAnd X'_minThe maximum value and the minimum value of the abscissa of the circumscribed rectangle of the polygon under the X 'Y' coordinate system.

The coordinates of the exposure point on a certain route are calculated, the intersection point of the route and the measuring area polygon can be calculated firstly, and then the center point (X ') is used'₀，Y′_m) And (4) as a starting point, respectively extending integral multiples of the shooting base line leftwards and rightwards in the maximum and minimum interval of the abscissa of the intersection point to obtain a series of intersection points, namely exposure points.

X′_k＝X′₀±B_k×k(k＝0，1，2...) (14)

In the formula B_kIs a baseline length.

If the route line has no intersection point or only one intersection point with the polygon, namely the route line is arranged outside the polygon of the survey area or intersects at a node at the top or the bottom of the polygon, then the center point (X'₀，Y′_m) As a starting point, in (X'_minX′_max) And respectively extending integral multiples of the shooting base line towards the left and the right in the interval to obtain a series of points, sequentially taking the points as exposure centers, calculating the coverage area of the photo on the ground, and if the area is overlapped with the polygon of the measuring area, taking the point as an exposure point.

Meanwhile, the requirement of aerial photography specifications is considered, course coverage exceeds a certain range of a shot region boundary line, for example, two base lines are added, and therefore, a corresponding number of exposure points are added outside the boundary.

5) DEM-based air route design

The DEM-based airline design is to combine the DEM and the GIS, fully consider the important role of topographic factors in the design of an aerial photography airline, take DEM data as the basis, take the GIS as technical support, take grids and vector diagrams as visual backgrounds, and solve the problems of zoning division of a survey area, parameter calculation, airline laying and the like in the current actual design through mathematical operation and condition judgment, thereby realizing the design of the aerial photography airline with high precision and high quality.

According to aerial photogrammetry specifications, a certain overlap is required between adjacent aerial photographic films so as to cover a surveying area and facilitate later three-dimensional surveying. The overlap ratio comprises a course overlap ratio and a sidewise overlap ratio, and the formula is as follows:

wherein P, Q is the overlapping part of the adjacent images in the course and side direction, x and y are the overlapping parts of the adjacent images in the course and side direction, respectively_x、l_yRespectively, the image width and the image width.

The topography will directly affect the heading and the side lap, the effect of which can be analyzed by equation (15). In addition, the topographic relief will cause a series of changes in the photography baseline and photography interval.

Wherein H is the height difference relative to the average elevation datum level, H_{Taking a photograph}For the relative navigational height of the aerial photography, P, Q is the actual course and the lateral overlapping rate, P 'and Q' are the planned course and the lateral overlapping rate, the DEM can reflect the terrain fluctuation most effectively, the h value of the required point can be acquired very quickly, and the computer rapid operation is provided.

The altitude values of the flight route and the image principal point can be obtained from the digital altitude model through a computer, the variation of the course lateral overlapping rate can be calculated according to the formula (16), and then the position of the adjacent image principal point and the position of the adjacent route can be calculated.

For the topographic relief area, the influence of DEM needs to be considered, firstly, the actual overlapping rate of the photo on the average plane is calculated according to the planned course overlapping rate of the photo, the length B of a photographing base line is calculated, and then the position O of the next image principal point is calculated according to the position of the image principal point and the course overlapping rate_i(ii) a Similarly, the interval D of the shooting route is calculated according to the lateral overlapping rate, and finally the position O of each image principal point on other routes is obtained according to the intervals D and B of the shooting routes_j。

d_x、D_ylane spacing widths on the picture and on the field;

L_x、L_ythe length and width of the photographic image;

p_x、q_ythe course and the lateral overlapping rate;

m_{navigation device}And is an aerial photography scale denominator.

The industrial personal computer 15 can display a map, a flight route, a flight track of the airplane, position information of the airplane and the like in real time, and on-board operators can control the time for turning on and off the remote sensing equipment 19 according to the displayed information, so that all the remote sensing equipment 19 can synchronously carry out remote sensing observation on the ground. The method comprises the following steps:

1) loading and displaying an electronic map of an administrative division;

3) acquiring longitude and latitude coordinates and time information of the airplane through a GNSS receiver, and converting the longitude and latitude coordinates into plane rectangular coordinates corresponding to an electronic map to display the position of the airplane on the electronic map;

4) displaying an airplane symbol, namely acquiring a position point where the current airplane is located; calling a symbol library; defining symbol objects and setting attributes; drawing a symbol object;

5) dynamic display of the flight path of the airplane, namely forming coordinate points of the airplane which are arranged according to a time sequence into line segments, and drawing the line segments representing the movement path of the airplane through a map control DrawShape function.

6) The on-board operator determines the time of the approach line of the airplane according to the position of the airplane, the flight line and the flight track of the airplane, and uses the industrial personal computer 15 to start the remote sensing equipment 19; and determining the time when the airplane leaves the route, and closing the remote sensing equipment 19 by using the industrial personal computer 15.

The SAR observation mode is a side view, the included angle between the incident beam of the antenna and the ground normal is set to be 30-60 degrees, namely the sampling angle range of the incident beam of the left SAR antenna is-30-60 degrees, and the sampling angle range of the incident beam of the right SAR antenna is set to be 30-60 degrees; the other remote sensing devices 19 are observed in a downward view with the angle between the incident beam of the sensor head and the ground normal set to-30, i.e. the sampling angle of the incident beam is-30. It can be seen that the side-looking sensing device 19 and the lower-looking sensing device 19 have different observation ranges to the ground under the same conditions. To ensure that the earth observation ranges of all remote sensing devices 19 are consistent, the following approach is taken:

1) open top stabilized platform control software in industrial computer 15, click "communication setting", set up the angle parameter, wherein, the scope of roll angle is established as: -30 ° - +30 °; the range of pitch angles is set as: -8 ° - +6 °; the range of the spin deflection angle is set as follows: -30 ° - +30 °;

2) determining the side overlapping rate in 50% -75% according to the task condition, making a flight plan, and generating a flight route; displaying a map, a flight route, a flight track of the airplane and position information of the airplane in the industrial personal computer 15;

3) when the first flight path 1 flying by the airplane is positioned at the west-most side or the south-most side of the operation area, informing a pilot to tilt the remote sensing airplane 13 obliquely flying leftwards and downwards by 30 degrees around the longitudinal axis of the airplane, and keeping the state to fly along the first flight path 1, wherein the gyro stable platform can automatically correct the roll angle at the moment, so that the remote sensing equipment 19 on the platform keeps a downward-looking ground-to-ground observation state;

4) control software of an SAR antenna turntable 40 is opened in an industrial personal computer 15, the turntable is arranged to incline leftwards and downwards, and the sampling angle range of an incident beam of the SAR antenna on the turntable is set to be-30 degrees to-60 degrees. At the moment, the sampling angle ranges of the incident beams of the ventral SAR antenna and the left SAR antenna are-30-0 degrees;

5) when the plane displayed on the industrial personal computer 15 enters a flight route, all the remote sensing devices 19 are turned on, and when the plane keeps the state and flies out of the flight route, all the remote sensing devices 19 are turned off;

6) turning the oblique flying remote sensing airplane 13, preparing to fly a second flight path, informing a pilot to tilt the oblique flying remote sensing airplane 13 downwards to the right by 30 degrees around the longitudinal axis of the airplane, and keeping the state to fly along the second flight path 5, wherein the gyro stable platform can automatically correct the roll angle at the moment, so that the remote sensing equipment 19 on the platform keeps a downward-looking earth observation state;

7) and (3) opening control software of an SAR antenna turntable 40 in the industrial personal computer 15, setting the turntable to incline downwards to the right, and setting the sampling angle range of the SAR antenna incident beam on the turntable to be 30-60 degrees. At the moment, the sampling angle ranges of the incident beams of the ventral SAR antenna and the right SAR antenna are both 0-30 degrees;

8) when the plane displayed on the industrial personal computer 15 enters a flight route, all the remote sensing devices 19 are turned on, and when the plane keeps the state and flies out of the flight route, all the remote sensing devices 19 are turned off;

9) and repeating the steps 3) -8) until all the air routes in the operation area are flown, and finishing the flight task.

10) When the first flight path 1 flying by the airplane is positioned at the most east or most north of the operation area, the pilot is informed to tilt the inclined flying remote sensing airplane 13 downwards by 30 degrees around the longitudinal axis of the airplane, and the inclined flying remote sensing airplane flies along the first flight path 1 in the state, at the moment, the gyro stable platform can automatically correct the roll angle, so that the remote sensing equipment 19 on the platform keeps a downward-looking ground-to-ground observation state;

11) and (3) opening control software of an SAR antenna turntable 40 in the industrial personal computer 15, setting the turntable to incline downwards to the right, and setting the sampling angle range of the SAR antenna incident beam on the turntable to be 30-60 degrees. At the moment, the sampling angle ranges of the incident beams of the ventral SAR antenna and the right SAR antenna are both 0-30 degrees;

12) when the plane displayed on the industrial personal computer 15 enters a flight route, all the remote sensing devices 19 are turned on, and when the plane keeps the state and flies out of the flight route, all the remote sensing devices 19 are turned off;

13) turning the oblique flying remote sensing airplane 13, preparing to fly a second flight path 5, informing a pilot to tilt the oblique flying remote sensing airplane 13 downwards and leftwards by 30 degrees around the longitudinal axis of the airplane, and keeping the state to fly along the second flight path 5, wherein the gyro stable platform can automatically correct the roll angle at the moment, so that the remote sensing equipment 19 on the platform keeps a downward-looking ground-to-ground observation state;

14) control software of an SAR antenna turntable 40 is opened in an industrial personal computer 15, the turntable is arranged to incline leftwards and downwards, and the sampling angle range of an incident beam of the SAR antenna on the turntable is set to be-30 degrees to-60 degrees. At the moment, the sampling angle ranges of the incident beams of the ventral SAR antenna and the left SAR antenna are-30-0 degrees;

15) when the plane displayed on the industrial personal computer 15 enters a flight route, all the remote sensing devices 19 are turned on, and when the plane keeps the state and flies out of the flight route, all the remote sensing devices 19 are turned off;

16) and repeating the steps 10) to 15) until all the air routes in the working area are flown, and finishing the flight task.

The included angle between the incident beam of the SAR antenna and the ground normal can be set to be other ranges, not limited to 30-60 degrees, or 20-50 degrees or 25-55 degrees, and the length of the range interval is less than 40 degrees; the side-looking remote sensing device 19 is also not limited to one type of SAR, and other side-looking remote sensing devices 19 such as oblique photography aerial cameras are also suitable.

Wherein the range resolution of the remote sensing device 19SAR is:

wherein tau is the pulse width of the SAR, C is the speed of light, and theta is the incident beam side view angle of the SAR antenna.

According to the above method, θ is changed from ± 45 ° to ± 15 °, which results in that Δ R becomes large, i.e., the distance resolution is lowered. In order to ensure that the distance resolution is not reduced, a chirp modulation technique can be used to modulate a wider pulse into a pulse with a large amplitude and a narrow width, i.e., reduce τ, thereby ensuring that the distance resolution is not reduced. The method comprises the following steps:

the harmonic wave is modulated by linear frequency to generate a linear frequency modulation pulse and then the pulse is transmitted, after receiving the echo, the pulse passes through a matched filter with the frequency characteristic opposite to that of the pulse during transmission on the frequency and time relationship, the received low-frequency echo is delayed on the filter greatly, and then the high-frequency echo is delayed slightly, so that the received pulse signal is extracted in a form of narrower width and larger amplitude.

Within the pulse width, the instantaneous frequency is linearly changed by f_minChange to f_maxFrequency modulation bandwidth Δ f ═ f_max-f_min. The envelope of the wave function generated by the echo through the matched filter (the envelope is a graph formed by interweaving a plurality of elliptic curves, the appearance looks like a bag, and the envelope has own unique meanings in mathematics, signal processing, literature, economy and traditional Chinese medicine) is

The waveform has a large main lobe, small side lobes and a half-power width of

And the larger Δ f, the smaller the compressed pulse width, and the smaller Δ R, the higher the range resolution.

when the sampling angle range of the incident beam of the left SAR antenna in the step 4) is-30-0 degrees, the sampling angle range of the incident beam of the corresponding right SAR antenna is changed to be 60-90 degrees, namely the lateral viewing angle of the incident beam of the right SAR antenna is 75 degrees. According to the trigonometric function principle, when the sampling angle is changed from 30 ° to 60 °, the corresponding ground coverage is changed from htan 30 ° to htan 60 °.

Wherein H is the relative navigational height of the airplane,

the coverage range of the ground can be calculated to be 3 times of the original coverage range, if the coverage range corresponding to the sampling angle of-30 degrees is the nth route 30 in the flight plan, the coverage range corresponding to the sampling angle of 60-90 degrees is the (3+ n) -nth route 30 in the flight plan, which is equivalent to acquiring data corresponding to the routes in advance; meanwhile, according to the method, the side view angle of the incident beam of the right SAR antenna is changed from 45 degrees to 75 degrees, and the distance resolution of the corresponding remote sensing data of the (3+ n) -th route 30 is improved (according to the previous steps, the SAR data obtains half lines less than other remote sensing equipment 19, so that the fewer lines can be made up, a certain range can be flown more than other remote sensing equipment 19, and the distance resolution is ensured). Similarly, step 7), step 11) and step 14) all have the features of step 4).

According to the invention, a special flying method is adopted in the flying process, and different devices are controlled by the industrial personal computer 15, so that coaxial remote sensing is realized by different types of sensors, namely, earth observation of the same earth surface area is realized under the same space-time environment, redundant flying is reduced, the working efficiency of aerial remote sensing is improved, and the aerial remote sensing task based on multiple sensors can be completed more quickly and conveniently.

Compared with the traditional aerial remote sensing, the remote sensing monitoring method can finish the remote sensing monitoring task more quickly and conveniently, and can obtain two achievements: 1) multi-source remote sensing data achievement; 2) coaxial remote sensing data results. Therefore, the work efficiency is improved.

Coaxial remote sensing: the method refers to that multiple sensors of different types realize remote sensing earth observation of the same area under the same space-time environment.

Oblique flying remote sensing aircraft: namely a remote sensing airplane with oblique flight capability, which can fly at a certain angle around the longitudinal axis of the airplane without failure under the condition of ensuring that a pilot seat is fixed, a staff seat is fixed and equipment instruments in the airplane are fixed.

A gyro stabilizing platform: the gyroscope platform and the inertial platform are used for short, and the device for keeping the platform body orientation stable by utilizing the characteristics of the gyroscope.

Positioning and orientation system: the Positioning and Orientation System (POS) integrates the dgps (differential gps) technology and the Inertial Navigation System (INS) technology, can acquire the spatial Position and three-axis attitude information of a moving object, and is widely applied to navigation and positioning of aircraft, ships and missiles.

An IMU: the device is used for measuring the three-axis attitude angle and acceleration of an object. Typical IMUs include a three-axis gyroscope and a three-axis accelerometer, and some 9-axis IMUs also include a three-axis magnetometer

GNSS: the GNSS is called Global Navigation Satellite System (Global Navigation Satellite System), which refers to all Satellite Navigation systems in general, including Global, regional, and enhanced systems, such as GPS in the united states, Glonass in russia, Galileo in europe, and beidou Satellite Navigation System in china, and related enhanced systems, such as WAAS (wide area augmentation System) in the united states, EGNOS in europe (european geostationary Navigation overlay System), MSAS in japan (multi-functional transportation Satellite augmentation System), and the like, and also covers other Satellite Navigation systems to be built and later built.

PWM: finger pulse width modulation. The pulse width modulation is an analog control mode, and the bias of a transistor base electrode or an MOS tube grid electrode is modulated according to the change of corresponding load to change the conduction time of the transistor or the MOS tube, so that the change of the output of the switching voltage-stabilized power supply is realized

TNC: an antenna interface.

BNC: a connector for coaxial cable.

FMS: short for flight management system.

RS-232: one of the commonly used serial communication interface standards, which was commonly established in 1970 by the american Electronic Industries Association (EIA) with bell systems, modem manufacturers, and computer terminal manufacturers, is named as "technical standard for serial binary data exchange interface between Data Terminal Equipment (DTE) and Data Communication Equipment (DCE)".

COM: serial communication port, called serial port for short.

LPT: and the printing terminal (line print terminal) is used for connecting a parallel communication port of a printer or a scanner.

It should be understood that the above-described embodiments of the present invention are merely examples for clearly illustrating the present invention, and are not intended to limit the embodiments of the present invention. Other variations and modifications will be apparent to persons skilled in the art in light of the above description. Not all embodiments are exhaustive. All obvious changes and modifications which are obvious to the technical scheme of the invention are covered by the protection scope of the invention.

Claims

1. An airborne coaxial remote sensing device based on multiple sensors, comprising:

the system comprises an oblique flying remote sensing airplane, a gyro stabilized platform, remote sensing equipment, an industrial personal computer, an antenna housing, an SAR antenna turntable, a GNSS antenna and a GNSS receiver;

the gyro stabilizing platform is fixedly connected with a downward-looking remote sensing window of the oblique flying remote sensing airplane, the remote sensing equipment is fixedly connected with the gyro stabilizing platform, the GNSS antenna is fixedly connected with the top of the oblique flying remote sensing airplane, the industrial personal computer is fixedly connected with the floor of the oblique flying remote sensing airplane, the antenna housing is fixedly connected with the belly and the machine side of the oblique flying remote sensing airplane, the SAR antenna is respectively and fixedly connected with the machine side of the oblique flying remote sensing airplane and the SAR antenna rotary table, the SAR antenna rotary table is fixedly connected with the belly of the oblique flying remote sensing airplane, the GNSS receiver is fixedly connected with the industrial personal computer, the GNSS antenna is connected with the GNSS receiver through a data line, the GNSS receiver is connected with the industrial personal computer through a data line, the industrial personal computer is connected with the remote sensing equipment through a data line, connected with the SAR antenna through a data line and connected with the gyro stabilizing platform through a data line.

2. The multi-sensor-based airborne coaxial remote sensing device according to claim 1, characterized in that the angle between the horizontal axis of the oblique flying remote sensing aircraft and the sea level parallel plane is 15 ° -30 °, the incident beam of the SAR antenna is shifted with the inclination of the oblique flying remote sensing aircraft, and the angle between the incident beam emitted by the SAR antenna and the ground normal is 30 ° -60 °;

the oblique flying remote sensing airplane comprises a structure mounting platform, a downward-looking optical window, optical glass and a photographic door, wherein the structure mounting platform is located above the downward-looking optical window, the optical glass is located on the downward-looking optical window, and the photographic door is located below the optical glass.

3. The multi-sensor-based airborne coaxial remote sensing device according to claim 2, wherein said remote sensing equipment comprises sensors of SAR, multispectral aerial camera, hyperspectral aerial camera, infrared aerial camera and airborne lidar;

the sensors of the multispectral aerial camera, the hyperspectral aerial camera, the infrared aerial camera and the airborne laser radar are all installed on the gyro stable platform, when the oblique flying remote sensing aircraft inclines, the gyro stable platform is adjusted to be vertical to the sea level to carry out remote sensing observation on the ground downwards, and downward-looking remote sensing observation on the ground is formed without being influenced by the angular motion of the aircraft;

the SAR and the gyro stabilizing platform are installed separately, and remote sensing observation to the ground is carried out through side view.

4. The multi-sensor-based airborne coaxial remote sensing device of claim 1,

the gyro stabilizing platform is arranged on the structure mounting platform and used for controlling the attitude of the remote sensing equipment;

the SAR antenna comprises an SAR antenna on the belly of the oblique flying remote sensing airplane, and SAR antennas on the left side and the right side of the oblique flying remote sensing airplane;

the SAR antenna of the belly of the oblique flying remote sensing aircraft comprises a belly antenna, an SAR antenna rotary table, a belly antenna mounting plate and a belly antenna cover, wherein the belly antenna mounting plate is mounted on the belly of the oblique flying remote sensing aircraft, the SAR antenna rotary table is mounted on the belly antenna mounting plate, the belly antenna is mounted on the SAR antenna rotary table, the belly antenna cover is mounted on the belly of the oblique flying remote sensing aircraft, the belly antenna is wrapped in the belly antenna cover, and the SAR antenna rotary table is used for controlling the position of the belly antenna to enable the belly antenna to incline leftwards or rightwards;

the SAR antennas on the left side and the right side of the oblique flying remote sensing airplane are symmetrically arranged on the left side and the right side of the abdomen of the oblique flying remote sensing airplane, the left SAR antenna comprises a left antenna, a left antenna mounting plate and a left SAR antenna housing, the left antenna mounting plate is arranged on the belly of the oblique flying remote sensing aircraft, the left antenna is arranged on the left antenna mounting plate, the left SAR antenna housing is arranged at the left side of the belly of the oblique flying remote sensing aircraft, and the left side antenna is wrapped in the left side SAR antenna housing, the right side SAR antenna comprises a right side antenna, a right side antenna mounting plate and a right side SAR antenna housing, the right antenna mounting plate is arranged on the belly of the oblique flying remote sensing aircraft, the right antenna is arranged on the right antenna mounting plate, the right SAR antenna housing is arranged on the right side of the belly of the oblique flying remote sensing aircraft, and a right antenna is wrapped in the right SAR antenna housing;

wherein, SAR antenna revolving stage includes revolving stage post, bearing, dead lever, buckle, angle sign, the revolving stage post passes through the bearing with the ventral antenna mounting panel is connected, the ventral antenna dress can rotate on the revolving stage post, revolving stage post upper surface is equipped with the angle sign, dead lever one end is fixed revolving stage post upper surface, the dead lever other end can with buckle on the ventral antenna mounting panel is fixed, makes the ventral antenna pass through on the revolving stage post upper surface the angle sign has been set for and has been fixed after observing the angle to ground.

5. The aviation coaxial remote sensing method based on the multiple sensors is characterized in that an industrial personal computer can make a flight plan of an oblique flying remote sensing airplane aiming at an operation area of aviation remote sensing, so that all remote sensing equipment on the oblique flying remote sensing airplane can carry out ground remote sensing observation along a specified flight route, and the method comprises the following steps:

step 1, first, geodetic coordinates (B) of a point are obtained using GPS₈₄ L₈₄ H₈₄)^TThen converted to space rectangular coordinates (X Y Z) by equation (1) according to the reference ellipsoid parameters of WGS84^TThen (X Y Z) is determined by formula (2) according to the reference ellipsoid parameters of Beijing 54 or Xian 80 or the local independent coordinate system^TConversion to geodetic coordinate form (B)₅₄ L₅₄ H₅₄)^TOr (B)₈₀ L₈₀ H₈₀)^TOr (B)_local L_local H_local)^TAnd finally, according to the central meridian, the elevation of the projection surface and the northbound east offset, the formula (3) is used for converting the (B) into the corresponding (B)₅₄ L₅₄)^TOr (B)₈₀ L₈₀)^TOr (B)_local L_local)^TThe projection is Gaussian coordinate (X)_g Y_g)^T；

Wherein the content of the first and second substances,

X＝C₀B+(C₂cosB+C₄cos³B+C₆cos⁵B+C₈cos⁷B)sinB (4)

t＝tanB (6)

l″＝L-L₀ (8)

wherein L, B is longitude and latitude coordinates before conversion; h is elevation, x and y are transformed Gaussian coordinates, a is the major radius of the ellipsoid, e is the first eccentricity of the ellipsoid, and L₀Center meridian longitude, C, of the projection zone₀、C₂、C₄、C₆、C₈Is a constant value related only to the ellipsoid parameter;

step 2, generating a buffer area to judge the relative position, when the oblique flying remote sensing aircraft enters the buffer area and simultaneously meets the flight altitude limiting condition to enter the flight path, considering the oblique flying remote sensing aircraft as an effective entry, when the oblique flying remote sensing aircraft shoots after entering the flight path, if the oblique flying remote sensing aircraft flies away from the preset flight path and exceeds the flight zone buffer area, giving a prompt by a system, and correspondingly automatically stopping shooting by an aviation sensor, thereby avoiding flight waste which does not accord with the flight path design;

step 3, firstly, rotating the coordinate system according to the route layout direction, enabling the X' axis of the rotated coordinate system to be parallel to the route direction, calculating the position of the route, and only needing to obtain the course central line and the number of routes of the survey area, and then symmetrically laying other routes to two sides in parallel to the course central line of the survey area; the ordinate of the course center line is:

Y′＝(Y′_max+Y′_min)/2 (9)

according to the requirements of national standard topographic map aerial photogrammetry internal work specifications, the sidewise coverage exceeds the boundary line of the shooting area by not less than 50% of the image frame, and is not less than 30% of the image frame at least; is provided with L_YFor the lateral coverage width of the image frame on the ground, the minimum total coverage width is designed as follows:

W_min＝Y′_max-Y′_min+2L_Y (10)

W＝((1-S)(n-1)+1)×L_Y (11)

wherein S is the lateral overlapping rate; the formula (11) was used to determine n as 1+ (W-L)_Y)/(L_Y-SL_Y) (ii) a n must be an integer, and the coverage width is guaranteed, n is rounded and added by 1, that is

n＝[1+(W-L_Y)/(L_Y-SL_Y)]+1 (12)

In the above formula, the parenthesis indicates rounding, and W is W_minSubstituting, and calculating the total number of the routes meeting the requirements;

deducing a calculation formula of the ordinate of each route according to the relevant knowledge of photogrammetry:

Y′_m＝(Y′_max+Y′_min)/2+(m-(n+1)/2)(1-S)×L_Y (13)

step 4, for the flat area, the length of the base line of the aerial photogrammetry area is not changed; taking central point coordinate X ' in polygon X ' direction of measured area '₀＝(X′_max+X′_min) (iii)/2, wherein, X'_maxAnd X'_minThe maximum value and the minimum value of the abscissa of the circumscribed rectangle of the polygon under the X 'Y' coordinate system;

calculating the coordinate of an exposure point on a preset air route, calculating the intersection point of the air route and a measuring area polygon, and then calculating the center point (X'₀，Y′_m) As a starting point, respectively extending integral multiples of a shooting baseline leftwards and rightwards in an intersection point abscissa maximum and minimum interval to obtain a series of intersection points, namely exposure points;

X′_k＝X′₀±B_k×k(k＝0，1，2...) (14)

in the formula B_kIs a base line long;

if the air route has no intersection point or only one intersection point with the polygon, the air route is arranged outside the polygon of the survey area or intersects at a node at the top or the bottom of the polygon, and the center point (X ') is used'₀，Y′_m) As a starting point, in (X'_minX′_max) Respectively extending integral multiples of a shooting baseline to the left and the right in the interval to obtain a series of points, sequentially taking the points as exposure centers, calculating a coverage area of the photo on the ground, and if the area is overlapped with a polygon of a measuring area, taking the point as an exposure point;

step 5, according to aerial photogrammetry specifications, overlapping is needed between adjacent aerial photography images to cover a surveying area and facilitate later three-dimensional surveying, and the overlapping rate is divided into a course overlapping rate and a lateral overlapping rate, and the formula is as follows:

wherein H is the height difference relative to the average elevation datum level, H_{Taking a photograph}P, Q is the actual course and the lateral overlapping rate, and P 'and Q' are the planned course and the lateral overlapping rate;

the elevation values of the flight route and the image principal point can be obtained from the digital elevation model through a computer, the variation of course lateral overlapping rate is calculated according to the formula (16), and then the position of the adjacent image principal point and the position of the adjacent route are calculated;

for the area with topographic relief, firstly, the actual overlapping rate of the photo on the average surface is calculated according to the planned course overlapping rate of the photo, the length B of a photographing baseline is calculated, and then the position O of the next image principal point is calculated according to the position of the image principal point and the course overlapping rate_i(ii) a Similarly, the interval D of the shooting route is calculated according to the lateral overlapping rate, and finally the position O of each image principal point on other routes is obtained according to the intervals D and B of the shooting routes_j；

In the formula: b_x、B_xFor the length of the base of the image on the picture and on the ground, d_x、D_yFor lane spacing width on picture and on the field, L_x、L_yFor the length and width of the photographic image, p_x、q_yM is the course and side lap ratio_{Navigation device}And is an aerial photography scale denominator.

6. The multi-sensor-based airborne coaxial remote sensing method of claim 5,

and 2, determining the relative position of the inclined flight remote sensing aircraft and the predetermined route through the feedback information of the GNSS equipment.

7. The multi-sensor-based airborne coaxial remote sensing method of claim 5, wherein,

loading and displaying an electronic map of an administrative division;

loading a flight plan file, and displaying a flight route on an electronic map;

acquiring longitude and latitude coordinates and time information of the oblique flying remote sensing airplane through a GNSS receiver, and converting the longitude and latitude coordinates into plane rectangular coordinates corresponding to an electronic map to display the position of the oblique flying remote sensing airplane on the electronic map;

acquiring a position point of the current oblique flying remote sensing airplane, calling a symbol library, and displaying symbols of the oblique flying remote sensing airplane;

forming line segments by coordinate points arranged according to a time sequence of the oblique flying remote sensing airplane, and drawing the line segments representing the motion trail of the oblique flying remote sensing airplane through a map control DrawShape function;

the on-board operator determines the time of the approach path of the oblique flying remote sensing aircraft according to the aircraft position, the flight path and the flight track of the oblique flying remote sensing aircraft, and uses an industrial personal computer to start remote sensing equipment; and determining the time when the oblique flying remote sensing aircraft leaves the air route, and closing the remote sensing equipment by using an industrial personal computer.

8. A multi-sensor based airborne coaxial remote sensing method according to claim 5, wherein

The SAR observation mode is that remote ground sensing observation is carried out in a side view, the included angle between the incident beam of the SAR antenna and the ground normal is set to be 30-60 degrees, wherein the sampling angle range of the incident beam of the left SAR antenna is-30-60 degrees, and the sampling angle range of the incident beam of the right SAR antenna is set to be 30-60 degrees;

the observation mode of the multispectral aerial camera, the hyperspectral aerial camera, the infrared aerial camera and the airborne laser radar remote sensing equipment on the gyro stabilized platform is downward viewing, the included angle between the incident beam of the multispectral aerial camera, the hyperspectral aerial camera, the infrared aerial camera and the airborne laser radar remote sensing equipment and the ground normal is set to be-30 degrees, and the sampling angle range of the incident beam is-30 degrees; in order to ensure that the earth observation ranges of the SAR and other remote sensing equipment are consistent, the following method steps are adopted:

9) repeating the step 3) to the step 8) until all air routes in the operation area are flown, and ending the flight task;

9. The method for multi-sensor based airborne coaxial remote sensing according to claim 5, characterized in that the range resolution of the remote sensing device SAR is:

within the pulse width, the instantaneous frequency is linearly changed by f_minChange to f_maxFrequency modulation bandwidth Δ f ═ f_max-f_min(ii) a The envelope of the wave function generated by the echo passing through the matched filter is

wherein f is_minIs the minimum instantaneous frequency, f_maxIs the maximum instantaneous frequency; sin c is a function of the sine,

10. the multi-sensor-based airborne coaxial remote sensing method according to claim 5, characterized in that when the sampling angle range of the incident beam of the left SAR antenna is-30 ° -0 °, the sampling angle range of the incident beam of the corresponding right SAR antenna becomes 60 ° -90 °, and the side view angle of the incident beam of the right SAR antenna is 75 °;

according to the trigonometric function principle, when the sampling angle is changed from 30 degrees to 60 degrees, the corresponding ground coverage range is changed from H tan30 degrees to H tan60 degrees;

wherein H is the relative navigational height of the airplane,

tan90°＝∞。