CN102393201A - Dynamic lever arm compensating method of position and posture measuring system (POS) for aerial remote sensing - Google Patents

Abstract

The invention provides a dynamic lever arm compensating method of a position and posture measuring system (POS) for aerial remote sensing. The method comprises the following steps of: to solve the problem of real-time variation of the lever arm between a measuring center of an inertia measuring unit (IMU) and phase center of a GPS (Global Positioning System) antenna due to rotation of a three-axis inertia stabilizing platform frame, obtaining an actual lever arm between the IMU measuring center and the phase center of the GPS antenna through calculating a dynamic lever arm between the center of the three-axis inertia stabilizing platform and the IMU measuring center in real time; and figuring out angular velocity of an initial coordinate system of the three-axis inertia stabilizing platform under the initial coordinate system of the three-axis inertia stabilizing platform relative to a local geographic coordinate system so as to compensate the dynamic lever arm. The dynamic lever arm compensating method provided by the invention has the characteristics of high accuracy, simplicity in operation and easiness for realization; the problem that the POS lever arm is hard to be accurately compensated while the three-axis inertia stabilizing platform is adopted for aerial remote sensing is solved; and the accuracies of POS and aerial remote sensing imaging load are improved.

Description

Airborne remote sensing is with position and dynamically lever arm compensation method of attitude measurement system (POS)

Technical field

The present invention relates to a kind of airborne remote sensing with position and dynamically lever arm compensation method of attitude measurement system (POS), belong to the airborne remote sensing field, be applied to adopt the airborne remote sensing of three inertially stabilized platforms, improved the precision of POS and airborne remote sensing imaging load.

Background technology

Airborne remote sensing be a kind of be carrier with the aircraft, utilize remote sensing load to obtain the hi-tech of the various spatial geographic informations of earth surface.Require load to do the at the uniform velocity ideal movements of straight line in the space when airborne remote sensing system carries out high-resolution imaging, but aircraft unavoidably can receive the influence of external disturbances such as fitful wind, turbulent flow, makes load depart from the ideal movements track, cause the load image quality to descend.Therefore, realize the high precision imaging of airborne remote sensing system, must isolate and motion compensation the flight disturbance.Three inertially stabilized platforms are made up of three frameworks, are held in as load level and point to the aircraft flight direction through three frameworks of servocontrol, thereby isolate the external disturbance in the flight course to a certain extent.Because three inertially stabilized platform loads are big; It is little to conduct oneself with dignity, and response speed is limited, and the disturbance of can not will flying is isolated fully; Therefore; Must use POS accurately to measure the flight disturbance of failing to isolate, obtain the kinematic parameters such as position, speed and attitude of load phase center that form images, and in imaging process, carry out motion compensation.

POS then is made up of IMU, GPS receiver, POS navigational computer (PCS) and the poster processing soft etc.Wherein IMU is used to measure three dimensional angular speed and the three-dimensional line acceleration that connects firmly carrier with it; Resolve through strap-down inertial, can obtain position, speed and the attitude information of carrier, have precision height in short-term; Advantages such as output is continuous and autonomous fully, but its navigation error accumulates in time.GPS then can provide high-precision position and velocity information for a long time, but exports discontinuously, and attitude information can not be provided, and gps signal receives and can not realize the location when blocking.POS utilizes inertial navigation and the natural complementarity of GPS navigation; The application message integration technology; The moment of inertia measurement information is merged with the GPS measurement information, can obtain the comprehensive kinematic parameter such as position, speed and attitude of carrier continuously, in real time, and accumulation in time of error.

When the GPS measurement information merges with the moment of inertia measurement information, must carry out the lever arm compensation.Because gps antenna can not be installed together with IMU; In order to receive gps satellite signal; Gps antenna generally is installed in the aircraft top, and IMU then is installed in engine room inside, and distance between the two is generally all more than 1 meter; But the positional precision of GPS and velocity accuracy can reach 0.05m and 0.005m/s respectively, therefore must position and the velocity information that GPS obtains be compensated to IMU measurement center through the lever arm that IMU measures between center and the gps antenna phase center.But in flight course; Inertially stabilized platform can be rotated three frameworks to be held in as load level and to point to the aircraft flight direction in real time; Thereby the relative orientation that causes IMU to measure between center and the gps antenna phase center constantly changes, and makes IMU measure the lever arm real-time change between center and the gps antenna phase center.Do not have relative orientation to change between traditional lever arm compensation method hypothesis IMU and the gps antenna, promptly the lever arm that measures between center and the gps antenna phase center of IMU is invariable, utilizes strap inertial navigation algorithm to resolve to obtain Battle array,

With lever arm measured value l ^bCarry out the lever arm compensation.Therefore, traditional lever arm compensation method is applied to adopt the airborne remote sensing of three inertially stabilized platforms can produce very big error even can not uses.

Summary of the invention

Technology of the present invention is dealt with problems and is: overcome the deficiency of prior art, propose a kind of airborne remote sensing with the dynamic lever arm compensation method of POS.This method is rotated to three inertially stabilized platform frameworks and is caused IMU to measure the problem of the lever arm real-time change between center and the gps antenna phase center; Through the dynamic lever arm between three inertially stabilized platform centers of real-time calculating and the IMU measurement center; Obtain IMU and measure the actual lever arm between center and the gps antenna phase center; And calculate the local relatively geographic coordinates of three inertially stabilized platform initial coordinate system in real time and tie up to three inertially stabilized platform initial coordinate system angular velocity down, carry out dynamic lever arm and compensate.The present invention has precision height, simple to operate, the characteristics that are easy to realize, has solved the problem that POS lever arm when airborne remote sensing is used three inertially stabilized platforms is difficult to fine compensation, has improved the form images precision of load of POS and airborne remote sensing.

Technical solution of the present invention is: a kind of airborne remote sensing is with the dynamic lever arm compensation method of POS, and concrete steps are following:

(1) under three inertially stabilized platform initial coordinate system, measures lever arm

and the lever arm

between three inertially stabilized platform centers and Inertial Measurement Unit (IMU) the measurement center between three inertially stabilized platform centers and the gps antenna phase center respectively

(2) calculate the direction cosine battle array that the gps data moment three inertially stabilized platform initial coordinate are tied to local geographic coordinate system;

(3) the direction cosine battle array of utilizing lever arm that step (1) obtains and step (2) to obtain, calculate gps data constantly IMU measure the dynamic lever arm between center and the gps antenna phase center;

(4) the direction cosine battle array of utilizing step (2) to obtain is calculated three local relatively geographic coordinates of inertially stabilized platform initial coordinate system and is tied up to three angular velocity under the inertially stabilized platform initial coordinate system;

(5) angular velocity that dynamic lever arm that the direction cosine battle array that obtains based on step (2), step (3) obtain and step (4) obtain; GPS position data and speed data are carried out dynamic lever arm compensation; And the gps data after will compensating and inertial data merge, and obtains optimum kinematic parameter;

(6) repeating step (2) finishes until the POS system data processing to step (5).

Principle of the present invention: rotate the problem that causes the lever arm real-time change between IMU measurement center and the gps antenna phase center to three inertially stabilized platform frameworks; The present invention is under three inertially stabilized platform initial coordinate systems; The dynamic lever arm l that IMU is measured between center and the gps antenna phase center is decomposed into the poor of two lever arms; Shown in Figure of description 2, calculate lever arm l ₁With lever arm l ₂Poor, can obtain dynamic lever arm l.Its Caused by Lever Arm l ₁Be the lever arm between three inertially stabilized platform centers and the gps antenna phase center, lever arm l ₂It is the dynamic lever arm between three inertially stabilized platform centers and the IMU measurement center.Can know l through comparative illustration book accompanying drawing 2a and Figure of description 2b ₁Be fixing lever arm, do not rotate and change along with the framework of inertially stabilized platform; l ₂Be dynamic lever arm, along with the framework of inertially stabilized platform rotates and changes.Through measuring the fixedly lever arm l between three inertially stabilized platform centers and the gps antenna phase center ₁, and calculate the dynamic lever arm l between three inertially stabilized platform centers and the IMU measurement center in real time ₂Thereby, can accurately obtain to utilize strap inertial navigation algorithm and three rotation relations of three inertially stabilized platforms to calculate again because three inertially stabilized platform frameworks rotate the lever arm l that the IMU that causes measures real-time change between center and the gps antenna phase center

Battle array,

With lever arm calculated value l ^b' carry out the Real-time and Dynamic lever arm to compensate.

The present invention's advantage compared with prior art is: the present invention measures the dynamic lever arm l between center and the gps antenna phase center through calculating IMU in real time ^b' with

Carry out the compensation of accurate dynamically lever arm, prior art has the high characteristics of precision relatively, and the POS lever arm is difficult to the problem of fine compensation when having solved three inertially stabilized platforms of airborne remote sensing use, has improved the precision of POS and airborne remote sensing imaging load.

Description of drawings

Fig. 1 is the dynamic lever arm compensation method of a POS of the present invention process flow diagram;

Fig. 2 is each subsystem relative orientation synoptic diagram of airborne remote sensing of the present invention, among the figure, and ox _{B '}y _{B '}z _{B '}Coordinate system is three inertially stabilized platform initial coordinate systems, ox _by _bz _bCoordinate system is three inertially stabilized platform inner frame coordinate systems, O _PBe three inertially stabilized platform centers, O _IFor IMU measures center, O _GBe the gps antenna phase center.Wherein, Fig. 2 a is three inertially stabilized platform inner frame coordinate system ox _by _bz _bWith three inertially stabilized platform initial coordinate be ox _{B '}y _{B '}z _{B '}Relative orientation synoptic diagram during coincidence; Fig. 2 b is three inertially stabilized platform inner frame coordinate system ox _by _bz _bWith three inertially stabilized platform initial coordinate be ox _{B '}y _{B '}z _{B '}Relative orientation synoptic diagram when not overlapping.

Embodiment

Shown in Figure of description 1, practical implementation of the present invention may further comprise the steps:

1, three inertially stabilized platforms are set to the leveling pattern; Three frameworks of three inertially stabilized platform control; Make the photoelectric coder of three of inertially stabilized platforms be output as zero, establishing at this moment, three inertially stabilized platform inner frame coordinate systems are that three inertially stabilized platform initial coordinate are ox _{B '}y _{B '}z _{B '}, with b ' expression; If three inner frame coordinate system ox that inertially stabilized platform is real-time _by _bz _bRepresent with b; If local geographic coordinate system ox _ny _nz _nRepresent with n.Three inertially stabilized platform initial coordinate is ox _{B '}y _{B '}z _{B '}Use three inertially stabilized platform center O of transit survey down, _PWith gps antenna phase center O _GBetween lever arm and three inertially stabilized platform center O _PAnd O between the IMU measurement center _ILever arm, obtain three inertially stabilized platform center O _PWith gps antenna phase center O _GBetween lever arm do Three inertially stabilized platform center O _PMeasure center O with IMU _IBetween lever arm do

Three inertially stabilized platforms are set to remote control mode then, follow the tracks of POS output, control in real time.Position relation between imaging load, three inertially stabilized platforms and IMU is seen Figure of description 2; Wherein three inertially stabilized platforms are installed on the airframe; Imaging load then is installed on three inertially stabilized platforms; Connect firmly with the inner frame of three inertially stabilized platforms, IMU then connects firmly with imaging load, measures the real-time kinematic parameter of imaging load.

2, calculate the direction cosine battle array

that the gps data moment three inertially stabilized platform initial coordinate are tied to local geographic coordinate system

(1) calculating the gps data moment three inertially stabilized platform initial coordinate is ox _{B '}y _{B '}z _{B '}To three inertially stabilized platform inner frame coordinate system ox _by _bz _bThe direction cosine battle array

Because the housing of three inertially stabilized platforms is the roll frame, center is the pitching frame, and inside casing is the course frame, so can get

$C_{b^{\′}}^b=\left[\begin{array}{ccc}\cos \left({\mathrm{\ψ}}_1\right)& \sin \left({\mathrm{\ψ}}_1\right)& 0\\ -\sin \left({\mathrm{\ψ}}_1\right)& \cos \left({\mathrm{\ψ}}_1\right)& 0\\ 0& 0& 1\end{array}\right]\left[\begin{array}{ccc}1& 0& 0\\ 0& \cos \left({\mathrm{\θ}}_1\right)& \sin \left({\mathrm{\θ}}_1\right)\\ 0& -\sin \left({\mathrm{\θ}}_1\right)& \cos \left({\mathrm{\θ}}_1\right)\end{array}\right]\left[\begin{array}{ccc}\cos \left({\mathrm{\γ}}_1\right)& 0& -\sin \left({\mathrm{\γ}}_1\right)\\ 0& 1& 0\\ \sin \left({\mathrm{\γ}}_1\right)& 0& \cos \left({\mathrm{\γ}}_1\right)\end{array}\right]$

Wherein, γ ₁The angle is gps data three angles that the inertially stabilized platform housing rotates with respect to the initial housing of inertially stabilized platform constantly, θ ₁The angle is gps data three angles that the inertially stabilized platform center rotates with respect to three initial centers of inertially stabilized platform constantly, ψ ₁The angle is gps data three angles that the inertially stabilized platform inside casing rotates with respect to three initial inside casings of inertially stabilized platform constantly.

Because three inertially stabilized platforms and GPS have independently clock system separately; The photoelectric coder data of three inertially stabilized platform outputs and gps data are difficult to fully synchronously; Be located at gps data constantly before the photoelectric coder data of three of the inertially stabilized platforms that obtain of sampling be respectively

and

gps data constantly the photoelectric coder data of three of the inertially stabilized platforms that obtain of post-sampling be respectively

and is all bigger owing to three each framework inertia of inertially stabilized platform; Can suppose that three inertially stabilized platform frame corners speed are constant under each SI, can get

$\left[\begin{array}{c}{\mathrm{\γ}}_1\\ {\mathrm{\θ}}_1\\ {\mathrm{\ψ}}_1\end{array}\right]=\left[\begin{array}{c}(P_{\mathrm{Ay}}^{+}-P_{\mathrm{Ay}}^{-})(T_{\mathrm{GPS}}-T_A^{-})/(T_A^{+}-T_A^{-})+P_{\mathrm{Ay}}^{-}\\ (P_{\mathrm{Ax}}^{+}-P_{\mathrm{Ax}}^{-})(T_{\mathrm{GPS}}-T_A^{-})/(T_A^{+}-T_A^{-})+P_{\mathrm{Ax}}^{-}\\ (P_{\mathrm{Az}}^{+}-P_{\mathrm{Az}}^{-})(T_{\mathrm{GPS}}-T_A^{-})/(T_A^{+}-T_A^{-})+P_{\mathrm{Az}}^{-}\end{array}\right]$

Wherein, T _GPSBe the gps data UTC time constantly,

For

With

The data sampling UTC time constantly,

For

With The data sampling UTC time constantly.

(2) calculate gps data three inertially stabilized platform inner frame coordinate system ox constantly _by _bz _bTo local geographic coordinate system ox _ny _nz _nThe direction cosine battle array

$C_b^n=\left[\begin{array}{ccc}\cos {\mathrm{\γ}}_2\cos {\mathrm{\ψ}}_2+\sin {\mathrm{\γ}}_2\sin {\mathrm{\θ}}_2\sin {\mathrm{\ψ}}_2& \cos {\mathrm{\θ}}_2\sin {\mathrm{\ψ}}_2& \sin {\mathrm{\γ}}_2\cos {\mathrm{\ψ}}_2-\cos {\mathrm{\γ}}_2\sin {\mathrm{\θ}}_2\sin {\mathrm{\ψ}}_2\\ -\cos {\mathrm{\γ}}_2\sin {\mathrm{\ψ}}_2+\sin {\mathrm{\γ}}_2\sin {\mathrm{\θ}}_2\cos {\mathrm{\ψ}}_2& \cos {\mathrm{\θ}}_2\cos {\mathrm{\ψ}}_2& -\sin {\mathrm{\γ}}_2\sin {\mathrm{\ψ}}_2-\cos {\mathrm{\γ}}_2\sin {\mathrm{\θ}}_2\cos {\mathrm{\ψ}}_2\\ -\sin {\mathrm{\γ}}_2\cos {\mathrm{\θ}}_2& \sin {\mathrm{\θ}}_2& \cos {\mathrm{\γ}}_2\cos {\mathrm{\θ}}_2\end{array}\right]$

Wherein, γ ₂, θ ₂, ψ ₂Be respectively three inertially stabilized platform inner frame coordinate system ox _by _bz _bLocal relatively geographic coordinate system ox _ny _nz _nRoll angle, the angle of pitch and course angle.

(3) can further be tried to achieve by above-mentioned analysis: gps data three inertially stabilized platform initial coordinate constantly is ox _{B '}y _{B '}z _{B '}To local geographic coordinate system ox _ny _nz _nThe direction cosine battle array

Can be by the gps data moment three inertially stabilized platform inner frame coordinate system ox _by _bz _bTo local geographic coordinate system ox _ny _nz _nThe direction cosine battle array With gps data constantly three inertially stabilized platform initial coordinate be ox _{B '}y _{B '}z _{B '}To three inertially stabilized platform inner frame coordinate system ox _by _bz _bThe direction cosine battle array Dot product obtains, promptly $C_{b^{\′}}^n=C_b^n{C}_{b^{\′}}^b$

3, calculate gps data moment IMU and measure the dynamic lever arm l between center and the gps antenna phase center ^b'

(1) calculates gps data three inertially stabilized platform center O constantly _PWith gps antenna phase center O _GBetween lever arm

Three inertially stabilized platform initial coordinate is ox _{B '}y _{B '}z _{B '}Down, inertially stabilized platform in three framework rotation processes of control, three inertially stabilized platform center O _PAnd there is not relative orientation to change between the aircraft, therefore three inertially stabilized platform center O _PWith gps antenna phase center O _GBetween relative orientation relation constant, three inertially stabilized platform center O that obtain by step 1 _PWith gps antenna phase center O _GBetween lever arm With

Equate, promptly

$l_1^{b^{\′}}=l_{01}^{b^{\′}}$

(2) calculate gps data three inertially stabilized platform center O constantly _PMeasure center O with IMU _IBetween lever arm

Because three real-time control frameworks of inertially stabilized platform rotate to be held in as load level and to point to the aircraft flight direction, make

Real-time change, but because IMU and three inertially stabilized platform inner frames connect firmly so IMU measurement center O _IAt three inertially stabilized platform inner frame coordinate system ox _by _bz _bPosition coordinates and IMU to measure the center be ox three inertially stabilized platform initial coordinate _{B '}y _{B '}z _{B '}Position coordinates identical, can get

$l_2^b=l_{02}^{b^{\′}}$

The gps data moment three inertially stabilized platform initial coordinate by obtaining in the step 2 are ox _{B '}y _{B '}z _{B '}To three inertially stabilized platform inner frame coordinate system ox _by _bz _bThe direction cosine battle array

Can get gps data three inertially stabilized platform inner frame coordinate system ox constantly through transposition _by _bz _bTo three inertially stabilized platform initial coordinate is ox _{B '}y _{B '}z _{B '}The direction cosine battle array

$C_b^{b^{\′}}=C_{b^{\′}}^{\mathrm{bT}}$

Thereby can get gps data three inertially stabilized platform center O constantly _PMeasure center O with IMU _IBetween lever arm

$l_2^{b^{\′}}=C_b^{b^{\′}}{l}_2^b$

(3) can further be tried to achieve by above-mentioned analysis: gps data IMU constantly measures center O _IWith gps antenna phase center O _GBetween dynamic lever arm l ^b' can be by the gps data moment three inertially stabilized platform center O _PWith gps antenna phase center O _GBetween lever arm With the gps data moment three inertially stabilized platform center O _PMeasure center O with IMU _IBetween lever arm

Difference obtain, promptly

$l^{b^{\′}}=l_1^{b^{\′}}-l_2^{b^{\′}}$

4, calculate three local relatively geographic coordinates of inertially stabilized platform initial coordinate system and tie up to three angular velocity

under the inertially stabilized platform initial coordinate system

(1) calculates three inertially stabilized platform inner frame coordinate system ox _by _bz _bRelative three inertially stabilized platform initial coordinate are ox _{B '}y _{B '}z _{B '}At three inertially stabilized platform inner frame coordinate system ox _by _bz _bUnder angular velocity

Can know by step 2, gps data constantly before the photoelectric coder data of three of the inertially stabilized platforms that obtain of sampling be respectively

gps data constantly the photoelectric coder data of three of the inertially stabilized platforms that obtain of post-sampling to be respectively the photoelectric coder cycle data that

and three inertially stabilized platforms export be 0.01 second.Because three each framework inertia of inertially stabilized platform are bigger, can suppose that between adjacent two sampling instants, three inertially stabilized platform frame corners speed are constant, can get three frame corners speed to be:

$w_{b^{\′}b}^b=\left[\begin{array}{c}{w}_x\\ w_y\\ w_z\end{array}\right]=\left[\begin{array}{c}(P_{\mathrm{Ax}}^{+}-P_{\mathrm{Ax}}^{-})/0.01\\ (P_{\mathrm{Ay}}^{+}-P_{\mathrm{Ay}}^{-})/0.01\\ (P_{\mathrm{Az}}^{+}-P_{\mathrm{Az}}^{-})/0.01\end{array}\right]$

When the photoelectric coder data noise of three inertially stabilized platforms output is big; Need earlier the photoelectric coder data to be carried out filtering; Adopt the method for interpolation to obtain the time dependent function of inertially stabilized platform three axis angular positions then, obtain the angular velocity of three of inertially stabilized platforms through constantly function being differentiated at gps data.

(2) calculating three inertially stabilized platform initial coordinate is ox _{B '}y _{B '}z _{B '}Local relatively geographic coordinate system ox _ny _nz _nThree inertially stabilized platform initial coordinate is ox _{B '}y _{B '}z _{B '}Under angular velocity

Because

$w_{\mathrm{in}}^n=w_{\mathrm{ie}}^n+w_{\mathrm{en}}^n$

Wherein,

Be local geographic coordinate system ox _ny _nz _nThe relative inertness coordinate system is at local geographic coordinate system ox _ny _nz _nUnder angular velocity,

For terrestrial coordinate system relative inertness coordinate system at local geographic coordinate system ox _ny _nz _nUnder angular velocity,

Be local geographic coordinate system ox _ny _nz _nRelatively spherical coordinate system is at local geographic coordinate system ox _ny _nz _nUnder angular velocity, and

$w_{\mathrm{ie}}^n=\left[\begin{array}{c}0\\ \cos \left(\mathrm{Lat}\right)\\ \sin \left(\mathrm{Lat}\right)\end{array}\right]$

$w_{\mathrm{en}}^n=\left[\begin{array}{c}-V_N^n/R_M\\ V_E^n/R_N\\ V_E^n\tan \left(\mathrm{Lat}\right)/R_N\end{array}\right]$

Wherein, Lat is a local latitude,

For flight carrier at local geographic coordinate system ox _ny _nz _nUnder east orientation speed,

For flight carrier at local geographic coordinate system ox _ny _nz _nUnder north orientation speed, R _MAnd R _NBe respectively the local meridian circle principal radius of curvature and the local prime vertical principal radius of curvature.

Can get

$w_{\mathrm{in}}^b=C_n^b{w}_{\mathrm{in}}^n$

Because

$w_{{\mathrm{ib}}^{\′}}^b=w_{\mathrm{ib}}^b-w_{b^{\′}b}^b$

Wherein,

Three inertially stabilized platform inner frame coordinate system ox for gyroscope output _by _bz _bThe relative inertness coordinate system is at three inertially stabilized platform inner frame coordinate system ox _by _bz _bUnder angular velocity,

Be that three inertially stabilized platform initial coordinate are ox _{B '}y _{B '}z _{B '}The relative inertness coordinate system is at three inertially stabilized platform inner frame coordinate system ox _by _bz _bUnder angular velocity.

Therefore can get

$w_{{\mathrm{nb}}^{\′}}^{b^{\′}}=C_b^{b^{\′}}(w_{{\mathrm{ib}}^{\′}}^b-w_{\mathrm{in}}^b)$

5, GPS position data and speed data are carried out dynamic lever arm compensation

(1) the GPS position data is carried out dynamic lever arm compensation

Gps data IMU constantly measures center O _IWith gps antenna phase center O _GBetween lever arm l ⁿ

$l^n=C_{b^{\′}}^n{l}^{b^{\′}}=\left[\begin{array}{c}{l}_E^n\\ l_N^n\\ l_U^n\end{array}\right]$

Wherein,

Be lever arm l ⁿAt local geographic coordinate system ox _ny _nz _nUnder east component,

Be lever arm l ⁿAt local geographic coordinate system ox _ny _nz _nUnder north component,

Be lever arm l ⁿAt local geographic coordinate system ox _ny _nz _nUnder the sky to component.

Gps antenna phase center O _GPosition data The IMU that obtains through the lever arm compensation measures center O _IPosition data

For

$P_{\mathrm{IMU}}^n=P_{\mathrm{GPS}}^n-l^n=\left[\begin{array}{c}\mathrm{Lat}-l_N^n/R_M\\ \mathrm{Lon}-l_E^n/R_N/\cos \left(\mathrm{Lat}\right)\\ H-l_U^n\end{array}\right]$

Wherein, Lat, Lon, H are respectively latitude, longitude and the height of GPS output.

(2) the GPS speed data is carried out dynamic lever arm compensation

Gps antenna phase center O _GSpeed data

The IMU that obtains through the lever arm compensation measures center O _ISpeed data

For

$V_{\mathrm{IMU}}^n=V_{\mathrm{GPS}}^n-C_{b^{\′}}^n{V}_l^{b^{\′}}$

Wherein

For the GPS speed data is ox three inertially stabilized platform initial coordinate _{B '}y _{B '}z _{B '}Under speed lever arm error, obtain by computes

$V_l^{b^{\′}}=w_{{\mathrm{nb}}^{\′}}^{b^{\′}}\×l^{b^{\′}}$

GPS position data and speed data after the compensation and inertial data are merged, obtain the kinematic parameter of optimum.

6, repeating step 2 finishes until the POS system data processing to step 5.

The content of not doing in the instructions of the present invention to describe in detail belongs to this area professional and technical personnel's known prior art.

Claims (6)

1. an airborne remote sensing is characterized in that may further comprise the steps with position and dynamically lever arm compensation method of attitude measurement system (POS):

(1) under three inertially stabilized platform initial coordinate system, measures lever arm

and the lever arm

between three inertially stabilized platform centers and Inertial Measurement Unit (IMU) the measurement center between three inertially stabilized platform centers and the gps antenna phase center respectively

(2) calculate the direction cosine battle array that the gps data moment three inertially stabilized platform initial coordinate are tied to local geographic coordinate system;

(3) the direction cosine battle array of utilizing lever arm that step (1) obtains and step (2) to obtain, calculate gps data constantly IMU measure the dynamic lever arm between center and the gps antenna phase center;

(4) the direction cosine battle array of utilizing step (2) to obtain is calculated three local relatively geographic coordinates of inertially stabilized platform initial coordinate system and is tied up to three angular velocity under the inertially stabilized platform initial coordinate system;

(5) angular velocity that dynamic lever arm that the direction cosine battle array that obtains based on step (2), step (3) obtain and step (4) obtain; GPS position data and speed data are carried out dynamic lever arm compensation; And the gps data after will compensating and inertial data merge, and obtains optimum kinematic parameter;

(6) repeating step (2) finishes until the POS system data processing to step (5).

2. a kind of airborne remote sensing according to claim 1 is characterized in that with position and dynamically lever arm compensation method of attitude measurement system (POS) three inertially stabilized platform initial coordinate in the said step (1) are ox _{B '}y _{B '}z _{B '}Be the photoelectric coder of the three inertially stabilized platforms inner frame coordinate system when being output as zero, ox _{B '}y _{B '}z _{B '}Coordinate system is with b ' expression.

3. a kind of airborne remote sensing according to claim 1 is characterized in that with position and dynamically lever arm compensation method of attitude measurement system (POS) computation process that the gps data moment three inertially stabilized platform initial coordinate in the said step (2) are tied to the direction cosine battle array of local geographic coordinate system is:

1) calculating the gps data moment three inertially stabilized platform initial coordinate is ox _{B '}y _{B '}z _{B '}To three inertially stabilized platform inner frame coordinate system ox _by _bz _bThe direction cosine battle array

$\left[\begin{array}{c}{\mathrm{\γ}}_1\\ {\mathrm{\θ}}_1\\ {\mathrm{\ψ}}_1\end{array}\right]=\left[\begin{array}{c}(P_{\mathrm{Ay}}^{+}-P_{\mathrm{Ay}}^{-})(T_{\mathrm{GPS}}-T_A^{-})/(T_A^{+}-T_A^{-})+P_{\mathrm{Ay}}^{-}\\ (P_{\mathrm{Ax}}^{+}-P_{\mathrm{Ax}}^{-})(T_{\mathrm{GPS}}-T_A^{-})/(T_A^{+}-T_A^{-})+P_{\mathrm{Ax}}^{-}\\ (P_{\mathrm{Az}}^{+}-P_{\mathrm{Az}}^{-})(T_{\mathrm{GPS}}-T_A^{-})/(T_A^{+}-T_A^{-})+P_{\mathrm{Az}}^{-}\end{array}\right]$

$C_{b^{\′}}^b=\left[\begin{array}{ccc}\cos \left({\mathrm{\ψ}}_1\right)& \sin \left({\mathrm{\ψ}}_1\right)& 0\\ -\sin \left({\mathrm{\ψ}}_1\right)& \cos \left({\mathrm{\ψ}}_1\right)& 0\\ 0& 0& 1\end{array}\right]\left[\begin{array}{ccc}1& 0& 0\\ 0& \cos \left({\mathrm{\θ}}_1\right)& \sin \left({\mathrm{\θ}}_1\right)\\ 0& -\sin \left({\mathrm{\θ}}_1\right)& \cos \left({\mathrm{\θ}}_1\right)\end{array}\right]\left[\begin{array}{ccc}\cos \left({\mathrm{\γ}}_1\right)& 0& -\sin \left({\mathrm{\γ}}_1\right)\\ 0& 1& 0\\ \sin \left({\mathrm{\γ}}_1\right)& 0& \cos \left({\mathrm{\γ}}_1\right)\end{array}\right]$

Wherein, γ ₁The angle is gps data three angles that the inertially stabilized platform housing rotates with respect to three initial housings of inertially stabilized platform constantly, θ ₁The angle is gps data three angles that the inertially stabilized platform center rotates with respect to three initial centers of inertially stabilized platform constantly, ψ ₁The angle is gps data three angles that the inertially stabilized platform inside casing rotates with respect to three initial inside casings of inertially stabilized platform constantly,

With

Be the photoelectric coder data of three of the gps data inertially stabilized platforms that sampling obtains before the moment,

With

Be the gps data photoelectric coder data of three of the inertially stabilized platforms that obtain of post-sampling constantly, T _GPSBe the gps data UTG time constantly,

For

With

The data sampling UTG time constantly,

For

With

The data sampling UTG time constantly;

2) calculate gps data three inertially stabilized platform inner frame coordinate system ox constantly _by _bz _bTo local geographic coordinate system ox _ny _nz _nThe direction cosine battle array

$C_b^n=\left[\begin{array}{ccc}\cos {\mathrm{\γ}}_2\cos {\mathrm{\ψ}}_2+\sin {\mathrm{\γ}}_2\sin {\mathrm{\θ}}_2\sin {\mathrm{\ψ}}_2& \cos {\mathrm{\θ}}_2\sin {\mathrm{\ψ}}_2& \sin {\mathrm{\γ}}_2\cos {\mathrm{\ψ}}_2-\cos {\mathrm{\γ}}_2\sin {\mathrm{\θ}}_2\sin {\mathrm{\ψ}}_2\\ -\cos {\mathrm{\γ}}_2\sin {\mathrm{\ψ}}_2+\sin {\mathrm{\γ}}_2\sin {\mathrm{\θ}}_2\cos {\mathrm{\ψ}}_2& \cos {\mathrm{\θ}}_2\cos {\mathrm{\ψ}}_2& -\sin {\mathrm{\γ}}_2\sin {\mathrm{\ψ}}_2-\cos {\mathrm{\γ}}_2\sin {\mathrm{\θ}}_2\cos {\mathrm{\ψ}}_2\\ -\sin {\mathrm{\γ}}_2\cos {\mathrm{\θ}}_2& \sin {\mathrm{\θ}}_2& \cos {\mathrm{\γ}}_2\cos {\mathrm{\θ}}_2\end{array}\right]$

Wherein, γ ₂, θ ₂, ψ ₂Be respectively three inertially stabilized platform inner frame coordinate system ox _by _bz _bLocal relatively geographic coordinate system ox _ny _nz _nRoll angle, the angle of pitch and course angle;

3) calculating the gps data moment three inertially stabilized platform initial coordinate is ox _{B '}y _{B '}z _{B '}To local geographic coordinate system ox _ny _nz _nThe direction cosine battle array

$C_{b^{\′}}^n=C_b^n{C}_{b^{\′}}^b.$

4. a kind of airborne remote sensing according to claim 1 is characterized in that in the said step (3) with position and dynamically lever arm compensation method of attitude measurement system (POS): the computation process that gps data moment IMU measures the dynamic lever arm between center and the gps antenna phase center is:

1) calculates gps data three inertially stabilized platform center O constantly _PMeasure center O with IMU _IBetween lever arm

$l_2^b=l_{02}^{b^{\′}}$

$C_b^{b^{\′}}=C_{b^{\′}}^{\mathrm{bT}}$

$l_2^{b^{\′}}=C_b^{b^{\′}}{l}_2^b$

Wherein

For at three inertially stabilized platform inner frame coordinate system ox _by _bz _bFollowing three inertially stabilized platform center O _PMeasure center O with IMU _IBetween lever arm,

For

Transposition;

2) calculate gps data IMU measurement constantly center O _IWith gps antenna phase center O _GBetween dynamic lever arm l ^b'

$l_1^{b^{\′}}=l_{01}^{b^{\′}}$

$l^{b^{\′}}=l_1^{b^{\′}}-l_2^{b^{\′}}.$

5. a kind of airborne remote sensing according to claim 1 is characterized in that in the said step (4) with the dynamically lever arm compensation method of position and attitude measurement system (POS): calculating the computation process that three local relatively geographic coordinates of inertially stabilized platform initial coordinate system tie up to the angular velocity of three inertially stabilized platform initial coordinate under being is:

1) calculates three inertially stabilized platform inner frame coordinate system ox _by _bz _bRelative three inertially stabilized platform initial coordinate are ox _{B '}y _{B '}z _{B '}At three inertially stabilized platform inner frame coordinate system ox _by _bz _bUnder angular velocity

$w_{b^{\′}b}^b=\left[\begin{array}{c}{w}_x\\ w_y\\ w_z\end{array}\right]=\left[\begin{array}{c}(P_{\mathrm{Ax}}^{+}-P_{\mathrm{Ax}}^{-})/T_s\\ (P_{\mathrm{Ay}}^{+}-P_{\mathrm{Ay}}^{-})/T_s\\ (P_{\mathrm{Az}}^{+}-P_{\mathrm{Az}}^{-})/T_s\end{array}\right]$

T wherein _sIt is the photoelectric coder sampling period of three inertially stabilized platforms;

2) calculating three inertially stabilized platform initial coordinate is ox _{B '}y _{B '}z _{B '}Local relatively geographic coordinate system ox _ny _nz _nThree inertially stabilized platform initial coordinate is ox _{B '}y _{B '}z _{B '}Under angular velocity

$w_{{\mathrm{ib}}^{\′}}^b=w_{\mathrm{ib}}^b-w_{b^{\′}b}^b$

$w_{\mathrm{ie}}^n=\left[\begin{array}{c}0\\ \cos \left(\mathrm{Lat}\right)\\ \sin \left(\mathrm{Lat}\right)\end{array}\right]$

$w_{\mathrm{en}}^n=\left[\begin{array}{c}-V_N^n/R_M\\ V_E^n/R_N\\ V_E^n\tan \left(\mathrm{Lat}\right)/R_N\end{array}\right]$

$w_{\mathrm{in}}^n=w_{\mathrm{ie}}^n+w_{\mathrm{en}}^n$

$w_{\mathrm{in}}^b=C_n^b{w}_{\mathrm{in}}^n$

$w_{{\mathrm{nb}}^{\′}}^{b^{\′}}=C_b^{b^{\′}}(w_{{\mathrm{ib}}^{\′}}^b-w_{\mathrm{in}}^b)$

Wherein,

Three inertially stabilized platform inner frame coordinate system ox for gyroscope output _by _bz _bThe relative inertness coordinate system is at three inertially stabilized platform inner frame coordinate system ox _by _bz _bUnder angular velocity,

Be that three inertially stabilized platform initial coordinate are ox _{B '}y _{B '}z _{B '}The relative inertness coordinate system is at three inertially stabilized platform inner frame coordinate system ox _by _bz _bUnder angular velocity,

For terrestrial coordinate system relative inertness coordinate system at local geographic coordinate system ox _ny _nz _nUnder angular velocity,

Be local geographic coordinate system ox _ny _nz _nRelatively spherical coordinate system is at local geographic coordinate system ox _ny _nz _nUnder angular velocity, Lat is a local latitude,

For flight carrier at local geographic coordinate system ox _ny _nz _nUnder east orientation speed,

For flight carrier at local geographic coordinate system ox _ny _nz _nUnder north orientation speed, R _MAnd R _NBe respectively the local meridian circle principal radius of curvature and the local prime vertical principal radius of curvature,

Be local geographic coordinate system ox _ny _nz _nThe relative inertness coordinate system is at local geographic coordinate system ox _ny _nz _nUnder angular velocity,

Be local geographic coordinate system ox _ny _nz _nThe relative inertness coordinate system is at three inertially stabilized platform inner frame coordinate system ox _by _bz _bUnder angular velocity.

6. a kind of airborne remote sensing according to claim 1 is characterized in that in the said step (5) with the dynamically lever arm compensation method of position and attitude measurement system (POS): GPS position data and speed data are carried out the computation process that dynamic lever arm compensates is:

1) the GPS position data is carried out dynamic lever arm compensation

$l^n=C_{b^{\′}}^n{l}^{b^{\′}}=\left[\begin{array}{c}{l}_E^n\\ l_N^n\\ l_U^n\end{array}\right]$

$P_{\mathrm{IMU}}^n=P_{\mathrm{GPS}}^n-l^n=\left[\begin{array}{c}\mathrm{Lat}-l_N^n/R_M\\ \mathrm{Lon}-l_E^n/R_N/\cos \left(\mathrm{Lat}\right)\\ H-l_U^n\end{array}\right]$

Wherein,

Be lever arm l ⁿAt local geographic coordinate system ox _ny _nz _nUnder east component, Be lever arm l ⁿAt local geographic coordinate system ox _ny _nz _nUnder north component,

Be lever arm l ⁿAt local geographic coordinate system ox _ny _nz _nUnder the sky to component, l ⁿBe gps data IMU measurement constantly center O _IWith gps antenna phase center O _GBetween lever arm, Lat, Lon, H are respectively latitude, longitude and the height of GPS output,

Gps antenna phase center O for GPS output _GPosition data,

For the IMU that obtains through the lever arm compensation measures center O _IPosition data

2) the GPS speed data is carried out dynamic lever arm compensation

$V_l^{b^{\′}}=w_{{\mathrm{nb}}^{\′}}^{b^{\′}}\×l^{b^{\′}}$

$V_{\mathrm{IMU}}^n=V_{\mathrm{GPS}}^n-C_{b^{\′}}^n{V}_l^{b^{\′}}$

Wherein,

For the GPS speed data is ox three inertially stabilized platform initial coordinate _{B '}y _{B '}z _{B '}Under speed lever arm error, * be multiplication cross,

Gps antenna phase center O for GPS output _GSpeed data, For the IMU that obtains through the lever arm compensation measures center O _ISpeed data.

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