CN104316920A - High-precision sea surface height extracting method of radar altimeter through small incidence angle interference - Google Patents
High-precision sea surface height extracting method of radar altimeter through small incidence angle interference Download PDFInfo
- Publication number
- CN104316920A CN104316920A CN201410630084.7A CN201410630084A CN104316920A CN 104316920 A CN104316920 A CN 104316920A CN 201410630084 A CN201410630084 A CN 201410630084A CN 104316920 A CN104316920 A CN 104316920A
- Authority
- CN
- China
- Prior art keywords
- interference
- main channel
- secondary channels
- phase
- complex number
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Pending
Links
Classifications
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01S—RADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES
- G01S13/00—Systems using the reflection or reradiation of radio waves, e.g. radar systems; Analogous systems using reflection or reradiation of waves whose nature or wavelength is irrelevant or unspecified
- G01S13/88—Radar or analogous systems specially adapted for specific applications
- G01S13/882—Radar or analogous systems specially adapted for specific applications for altimeters
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02A—TECHNOLOGIES FOR ADAPTATION TO CLIMATE CHANGE
- Y02A10/00—TECHNOLOGIES FOR ADAPTATION TO CLIMATE CHANGE at coastal zones; at river basins
- Y02A10/40—Controlling or monitoring, e.g. of flood or hurricane; Forecasting, e.g. risk assessment or mapping
Landscapes
- Engineering & Computer Science (AREA)
- Radar, Positioning & Navigation (AREA)
- Remote Sensing (AREA)
- Physics & Mathematics (AREA)
- Electromagnetism (AREA)
- Computer Networks & Wireless Communication (AREA)
- General Physics & Mathematics (AREA)
- Radar Systems Or Details Thereof (AREA)
Abstract
The invention relates to a high-precision sea surface height extracting method of a radar altimeter through small incidence angle interference. A small incidence angle and short base line interference processing mode is adopted to carry out synchronous interference receiving on echo signals through a main channel and an auxiliary channel, pre-filtering, two-dimensional image processing, image registration, interference processing, multi-vision processing, phase-position denoising filtering, phase position unwinding, water recognizing, classifying, height conversion and geometric correcting processing are carried out on received data in sequence, and a water area height value is obtained. According to the method, the swath width is large, the temporal-spatial resolution is high, the method can be applied to observation of the ocean current, ocean tide, vortex and other meso and micro scale phenomena in the ocean and the observation of the coastal water, the sea ice shelf and the land hydrology.
Description
Technical field
The present invention relates to radar altimeter technical field, particularly relate to the sea level height high-precision method for extracting that the little incident angle of a kind of radar altimeter is interfered.
Background technology
The domestic and international space remote sensing equipment for the mapping of earth ground level mainly comprises interference synthetic aperture radar, radar altimeter these two kinds at present, the echo data that wherein interference synthetic aperture radar utilizes multiple receiving antenna or individual antenna repeatedly to observe to obtain carries out interference treatment, extract the elevation information on ground, general employing be the interference technique of large incident angle (being greater than 30 °) Long baselines, be mainly used in the measurement of land elevation.Radar altimeter is mainly used in the elevation carrection of ocean, sea ice ice shelf, most altitude gauge mainly adopts the end depending on detection for the height extracting method on sea, entirely goes oblique and possibility predication tracking etc., it operationally, Chirp signal generator produces the Chirp pulse of a large bandwidth, through up-conversion and after amplifying, go out through antenna transmission.The end depending on antenna illuminate the sea at plumb point place, and receive the radar signal returned from plumb point, the signal received is after amplifying through low noise and after mixing, then De-chirp method is carried out, when entirely going oblique, echoed signal does difference frequency process with transmitting through the Chirp of suitable time-delay, AD(modulus is carried out to entirely going the echoed signal tiltedly) gather, orthogonal detection, after low-pass filtering, be sent to power spectrumanalysis processor (igh-speed wire-rod production line unit or special FFT fast fourier transform processor) and be transformed to power-delay signal, the power spectrum signal obtained is carried out to the estimation of parameter, according to the result of parameter estimation to AGC(automatic growth control), sequential and ADC(analog to digital converter) sample and carry out control adjustment, to complete the code acquisition and height tracing etc. of echo.The data of altitude gauge send satellite data interface to, then pass land station back, carry out follow-up process such as heavily tracking, correction etc. on ground, high-precision sea-level elevation can be completed and extract, altimetry precision can reach cm level, and spatial resolution is generally about tens kms or tens kms.Another sea level height extracting method is on said method basis, synthetic aperture processing method is looked to the employing end in straight rail, by carrying out Doppler beam sharpening and compensation of delay process to multiple echo, realize orientation to beam sharpening, straight rail improves greatly to resolution, and simultaneous altitude extraction accuracy is corresponding raising also.
Domestic current altitude gauge is in orbit traditional third generation altitude gauge, all adopts traditional end depending on detection, entirely removes oblique and possibility predication tracking.
In patent, the Zhang Hong of China Remote Satellite Earth Station, CAS, Chen Xi, Wang Chao has applied for the method (publication number: CN101078769A) of patent-one-time all-polarization synthetic aperture radar image inverse digital elevation model on the Research foundation of interference synthetic aperture radar, this patent is the features in conjunction with polarization radar and radar angle measurement technology, from the method for one-time all-polarization synthetic aperture radar image inverse digital elevation model, the method takes large incident angle to irradiate, elevation extraction precision is in m level, land DEM(digital elevation model can only be used for) mapping, sea can not be used for, the acquisition of sea ice ice shelf height.Tom's Paul McDowell of the Harris Corp of the U.S., Jack's Losec Xi Er, mark draws Hermes, the people such as Lei Fuermu have applied for that patent-base area form point carries out the exposed Earth Digital Elevation Model extraction (patent No.: 200580023901) of three-dimensional registration, that patent describes a kind of system for extracting exposed Earth Digital Elevation Model in the multiple form points primitively from expression multidimensional object, described multidimensional object comprises ground and ground barrier, represent that described multiple form points primitively of multiple frame find floor surface by receiving, each frame represents the part on described surface, and filter out ground point from ground obstacle object point, to provide the multiple ground points representing described floor surface.The method can only be used for the mapping of land DEM, and desirably EDS maps has reference mark, can not be used for the extraction of sea, sea ice ice shelf height.Feng Xiao, Tang Baimin of Chongqing Jiaotong University have applied for patent-a kind of ridge crossing line method for designing (patent No.: 200810069413) based on digital complex demodulation, that patent describes a kind of ridge crossing line method for designing based on digital complex demodulation, comprise the steps: based on digital elevation model, set up route selection district digital terrain model; Specify ridge crossing line starting point and terminal; Landforms in alignment region are analyzed; Determine bealock reference mark and step-by-step design uplink and downlink circuit; Tentatively slope is drawn by average gradient; Average gradient differentiates; Transitional gradient is arranged; Intersection point merges adjustment; Knick point merges adjustment; Evaluate alternatives.The method can utilize the function of computing machine effectively, fully, is automatically completed by the evaluation work that current artificial paper location of line cannot complete at all by computing machine; More artificial route selection improves work efficiency decades of times; And the quality of route selection can be guaranteed.The more ridge route plan that earthwork is minimum, cost is minimum can be tried to achieve under prescribed conditions.The method also can only be used for the mapping of land DEM, can not be used for the acquisition of ocean surface height.Traditional extracting method for sea level height (end is depending on detecting, entirely going tiltedly and possibility predication tracking), due to technology maturation, does not have relevant patent.
Up to now, the patent for sea level height extracted with high accuracy aspect not adopting little incident angle to interfere.
Summary of the invention
The invention provides the sea level height high-precision method for extracting that the little incident angle of a kind of radar altimeter is interfered, little incident angle (2 ° ~ 6 °) Short baseline interference treatment mode is taked when radar altitude measurement is high, swath width is large and spatial and temporal resolution is high, the observation of the ocean Small and Medium Sized phenomenons such as ocean current, oceanic tide, vortex can be applied to, and coastal waters, sea ice ice shelf, Hydrology observation.
In order to achieve the above object, the invention provides a kind of little incident angle Short baseline radar altimeter, comprise:
Be separately positioned on the main interference antenna at baseline two ends and auxiliary interference antenna;
Be electrically connected the main transmit-receive switch circuit of main interference antenna;
Be electrically connected the anti tr switch circuit of auxiliary interference antenna;
Be electrically connected the main channel receiver module of main transmit-receive switch circuit;
Be electrically connected the secondary channels receiver module of anti tr switch circuit;
Be electrically connected the transmitter module of main transmit-receive switch circuit;
Be electrically connected the signal processing unit of main channel receiver module and secondary channels receiver module;
Ranges of incidence angles when radar altitude measurement is high is for being more than or equal to 2 °, and being less than or equal to 6 ° of base length scopes is 2m ~ 15m.
Described main channel receiver module comprises the main channel receiver being electrically connected main transmit-receive switch circuit, and is electrically connected the primary memory of main channel receiver and signal processing unit;
Described secondary channels receiver module comprises the secondary channels receiver being electrically connected anti tr switch circuit, and is electrically connected the secondary store of secondary channels receiver and signal processing unit;
Described transmitter module comprises the transmitter being electrically connected main transmit-receive switch circuit, and is electrically connected the Chirp generator of transmitter, main channel receiver, secondary channels receiver and control module.
FPGA circuit and high-speed a/d sample circuit is comprised in described main channel receiver;
FPGA circuit and high-speed a/d sample circuit is comprised in described secondary channels receiver.
The present invention also provides a kind of radar altimeter sea level height high-precision method for extracting that little incident angle is interfered, and comprises following steps:
The Chirp generator of step 1, radar altimeter produces the Chirp signal of large bandwidth, and after transmitter, by main interference antenna to be more than or equal to 2 °, the little incident angle being less than or equal to 6 ° is launched;
Step 2, main interference antenna and auxiliary interference antenna carry out coherent reception to echoed signal simultaneously, obtain main channel raw data and secondary channels raw data respectively;
FPGA circuit in step 3, main channel receiver forms main channel I road signal and Q road, main channel signal after carrying out quadrature demodulation to main channel raw data, the FPGA circuit in secondary channels receiver forms secondary channels I road signal and secondary channels Q road signal after carrying out quadrature demodulation to secondary channels raw data;
High-speed a/d sample circuit in step 4, main channel receiver carries out high speed analog-digital conversion sampling to main channel I road signal and Q road, main channel signal, sampled signal is stored in primary memory, high-speed a/d sample circuit in secondary channels receiver carries out high speed analog-digital conversion sampling to secondary channels I road signal and secondary channels Q road signal, sampled signal is stored in secondary store;
Step 5, signal processing unit carry out pre-filtering to the two ways of digital signals after primary memory and the sampling of secondary store high speed modulus;
Step 6, signal processing unit carry out the process of SAR two-dimensional imaging to the digital signal after pre-filtering and obtain main channel two-dimensional complex number image and secondary channels two-dimensional complex number image;
Step 7, signal processing unit carry out image registration to the main channel two-dimensional complex number image obtained and secondary channels two-dimensional complex number image, a pair pixel in two width images after registration is made to correspond to the same resolution element on ground, to ensure the coherence of the two width images that main channel and secondary channels receive;
Step 8, signal processing unit carry out interference treatment to the main channel two-dimensional complex number image after image registration and secondary channels two-dimensional complex number image, obtain original interference phase diagram, interfere map of magnitudes and related coefficient figure;
Step 9, signal processing unit go level land Phase Processing to original interference phase place, that is, original interference phase place is cut the interferometric phase of reference planes;
Step 10, signal processing unit carry out multiple look processing to the interferometric phase after past level land Phase Processing;
Step 11, signal processing unit carry out the process of phase place noise reduction filtering to the interferometric phase after multiple look processing;
Step 12, signal processing unit carry out phase unwrapping around process to the interferometric phase after the process of phase place noise reduction filtering;
Step 13, signal processing unit carry out true phase calculating, that is, by adding the interferometric phase of reference planes through the interferometric phase of phase unwrapping after process, obtain final true phase value φ;
Step 14, signal processing unit carry out identifying water boy and classification process to the interference map of magnitudes of main channel and secondary channels and related coefficient figure, extract the final true phase value φ in waters;
Step 15, signal processing unit (3) the final true phase value to the waters of extracting after identifying water boy and classification process carries out altitude conversion and Geometry rectification process, obtains sea level height value h;
（4）
Wherein, H is the height of the carrying platform of radar altimeter, and θ is the incident angle of main interference antenna 101,
inclination angle formed by baseline and horizontal line, R1 is the distance of certain point of ground and main interference antenna 101, and B is base length, and λ is radar wavelength, and φ is the interferometric phase that last solution calculates, and antenna base length B immobilizes.
In described step 5, signal processing unit arranges distance pulse pressure wave filter and Azimuth Compression wave filter according to grazing angle and Squint angle, carries out pre-filtering to the two ways of digital signals after high speed analog-digital conversion sampling.
In described step 7, adopt cross correlation image registration method, simultaneously in conjunction with the metrical information of spaceborne GPS device and star sensor, to improve registration accuracy.
In described step 8, the calculating of each the original interference phase place in original interference phase diagram comprises following steps:
First by the pixel in a width two-dimensional complex number image
get conjugation, then with the respective pixel in another width two-dimensional complex number image
be multiplied, then the phase place after being multiplied taken out, original interference phase place can be obtained
(1);
The calculating of each the interference amplitude in map of magnitudes is interfered to comprise following steps:
By the pixel in the two-dimensional complex number image of main channel
get conjugation, then with the respective pixel in secondary channels two-dimensional complex number image
be multiplied, then the range value after being multiplied taken out, can obtain interfering map of magnitudes
, wherein m, n representative is the position of pixel;
The calculating of each related coefficient in related coefficient figure comprises following steps:
In formula,
represent main channel two-dimensional complex number image value,
represent secondary channels two-dimensional complex number image value, m, n representative be the position of pixel, M, the N window size parameter for adopting when calculating.
In described step 10, multiple look processing obtains the method that the data of two passages in same marine site are divided by sub-aperture image process or frequency domain doppler bandwidth
width looks subimage pair more, then to do after conjugate multiplication the corresponding double image element of every a pair in addition average, obtains the two-dimensional complex number image value of interferogram, namely
（2）
Wherein
represent and look number more,
with
represent the
depending on the respective pixel in image after a pair complex image corregistration;
Right
carry out process and obtain interferometric phase
, wherein m, n representative is the position of pixel, the now two-dimensional complex number image value of interferogram
standard deviation depend on the related coefficient of two width images
size and look more look number
;
The related coefficient of main channel two-dimensional complex number image and secondary channels two-dimensional complex number image
be defined as:
（3）
Wherein Σ represents mathematics summation operation, and f1 represents the two-dimensional complex number image value of main channel two-dimensional complex number image, and f2 represents the two-dimensional complex number image value of secondary channels two-dimensional complex number image.
In described step 12, phase unwrapping adopts Branch cut and Quality Map to instruct method around process, simultaneously in conjunction with the metrical information of spaceborne GPS device and star sensor, to improve unwrapping precision.
In described step 14, the threshold value of setting interference amplitude is 0.5, interferes in map of magnitudes, and waters is regarded as in the continuum that interference amplitude is less than 0.5 namely; Waters is regarded as in the region that related coefficient is less than 0.4.
The present invention compared with prior art, has the following advantages:
1, swath width is large and spatial and temporal resolution is high:
When traditional radar altimeter takes the end to look observation, cannot solve radar altimeter and observe swath width little and the problem that spatial and temporal resolution is not high, it measures swath width range about tens kms, and spatial resolution is generally about tens kms or tens kms.
And the present invention takes the interference technique of little incident angle, just can realize wide swath high-resolution surveys high, measure swath width range and can increase by tens kms even hundred kilometers on the basis of conventional height meter, sea spatial resolution can reach 1km × 1km even about 500m × 500m, simultaneously because observation swath is larger, satellite orbit pitch smaller, is more conducive to the change of the ocean surface height that detection causes due to Small and Medium Sized ocean current.
2, function and object of observation variation:
When radar altimeter traditional at present takes the end to look observation, because observation swath width is little and spatial and temporal resolution is not high, be mainly used in the observation of the large mesoscale of ocean, also can carry out the observation of part sea ice ice shelf in addition.
And after the present invention takes the interference technique of little incident angle, the observation of the ocean Small and Medium Sized phenomenons such as ocean current, oceanic tide, vortex can be applied to, and coastal waters, sea ice ice shelf, Hydrology observation.
Accompanying drawing explanation
Fig. 1 is the circuit structure block diagram of radar altimeter.
Fig. 2 is process flow diagram of the present invention.
Fig. 3 is sea geometric model schematic diagram.
Fig. 4 is that high simulation result is surveyed on sea.
Embodiment
Following according to Fig. 1 ~ Fig. 4, illustrate preferred embodiment of the present invention.
Hardware device in radar altimeter provided by the invention uses for reference the circuit design of interference synthetic aperture radar, and as shown in Figure 1, radar altimeter comprises:
Be separately positioned on the main interference antenna 101 at baseline two ends and auxiliary interference antenna 201;
Be electrically connected the main transmit-receive switch circuit 102 of main interference antenna 101;
Be electrically connected the anti tr switch circuit 202 of auxiliary interference antenna 201;
Be electrically connected the main channel receiver module of main transmit-receive switch circuit 102;
Be electrically connected the secondary channels receiver module of anti tr switch circuit 202;
Be electrically connected the transmitter module of main transmit-receive switch circuit 102;
Be electrically connected the signal processing unit 3 of main channel receiver module and secondary channels receiver module;
And, be electrically connected the control module 4 of signal processing unit 3 and transmitter module.
Described main channel receiver module comprises the main channel receiver 103 being electrically connected main transmit-receive switch circuit 102, and is electrically connected the primary memory 104 of main channel receiver 103 and signal processing unit 3;
Described secondary channels receiver module comprises the secondary channels receiver 203 being electrically connected anti tr switch circuit 202, and is electrically connected the secondary store 204 of secondary channels receiver 203 and signal processing unit 3;
Described transmitter module comprises the transmitter 6 being electrically connected main transmit-receive switch circuit 102, and is electrically connected the Chirp generator 5 of transmitter 6, main channel receiver 103, secondary channels receiver 203 and control module 4.
FPGA circuit and high-speed a/d sample circuit is comprised in described main channel receiver 103.
FPGA circuit and high-speed a/d sample circuit is comprised in described secondary channels receiver 203.
Adopt from the radar altimeter receiver in different the present invention of being exactly that traditional radar altimeter circuit is maximum and entirely receive system, instead of traditional entirely go mitered acceptor system.
Chirp generator 5 produces the Chirp signal of large bandwidth, after transmitter 6, launched from main interference antenna 101 by main transmit-receive switch circuit 102, transmitter 6 mainly comprises upconverter, wave filter, power amplification etc., echoed signal is respectively by main interference antenna 101 and the coherent reception simultaneously of auxiliary interference antenna 102, I is formed respectively after the FPGA circuit quadrature demodulation in main channel receiver 103 and secondary channels receiver 203, Q signal, sampled by high-speed a/d sample circuit (model is AD9225ARS) again, finally be stored in primary memory 104 and secondary store 204 respectively, binary channels imaging is carried out again by signal processing unit 3, image registration, phase place noise reduction filtering, go level land phase place and phase unwrapping around etc., carry out that elevation resolves etc. and therefrom obtain the elevation information on sea, control module 4 controls mode of operation and the state of whole radar altimeter, adjustment work schedule, adjustment intermittent phase size etc.
Little incident angle (2 ° ~ 6 °) Short baseline is taked to interfere (when base length scope is 2m ~ 15m, be called that Short baseline is interfered, in the present invention, base length is 10m) processing mode when radar altitude measurement is high.
As shown in Figure 2, the invention provides the sea level height high-precision method for extracting that the little incident angle of a kind of radar altimeter is interfered, comprise following steps:
The Chirp generator 5 of step 1, radar altimeter produces the Chirp signal of large bandwidth (bandwidth range 200M ~ 500M), after transmitter 6, is launched with little incident angle by main interference antenna 101;
The scope of described little incident angle, for being more than or equal to 2 °, is less than or equal to 6 °;
Step 2, main interference antenna 101 and auxiliary interference antenna 201 carry out coherent reception to echoed signal simultaneously, obtain main channel raw data and secondary channels raw data respectively;
FPGA circuit in step 3, main channel receiver 103 forms main channel I road signal and Q road, main channel signal after carrying out quadrature demodulation to main channel raw data, the FPGA circuit in secondary channels receiver 203 forms secondary channels I road signal and secondary channels Q road signal after carrying out quadrature demodulation to secondary channels raw data;
High-speed a/d sample circuit in step 4, main channel receiver 103 carries out high speed analog-digital conversion sampling to main channel I road signal and Q road, main channel signal, sampled signal is stored in primary memory 104, high-speed a/d sample circuit in secondary channels receiver 203 carries out high speed analog-digital conversion sampling to secondary channels I road signal and secondary channels Q road signal, sampled signal is stored in secondary store 204;
Two ways of digital signals after the sampling of step 5, signal processing unit 3 pairs of primary memorys 104 and secondary store 204 high speed modulus carries out pre-filtering; Signal processing unit 3 arranges distance pulse pressure wave filter and Azimuth Compression wave filter according to grazing angle and Squint angle, carries out pre-filtering to the two ways of digital signals after high speed analog-digital conversion sampling;
With general formation method unlike, between the two width images formed to make main channel receiver 103 and secondary channels receiver 203, there is higher coherence, consider SAR(synthetic-aperture radar Synthetic Aperture Radar) image obtains from the matched filtering of actual scene by system response function, and system response function is relevant with many practical factors, therefore, the system response function of the two width images formed for making main channel receiver 103 and secondary channels receiver 203 is accurately consistent, pre-filtering is carried out to the two ways of digital signals after high speed analog-digital conversion sampling,
Digital signal after step 6, signal processing unit 3 pairs of pre-filterings is carried out the process of SAR two-dimensional imaging and is obtained main channel two-dimensional complex number image and secondary channels two-dimensional complex number image;
Adopt SAR two-dimensional imaging algorithm, to the imaging respectively of the digital signal after the digital signal after the pre-filtering of main channel and secondary channels pre-filtering, obtaining Same Scene and observe two the two-dimensional complex number images obtained, is main channel two-dimensional complex number image and secondary channels two-dimensional complex number image respectively;
In SAR two-dimensional imaging processing procedure, inevitably use the various estimation in imaging and backoff algorithm, as Frequency Estimation, auto-focus method etc. are adjusted in Doppler center estimation, doppler bandwidth estimation, orientation.
Step 7, signal processing unit 3 carry out image registration to the main channel two-dimensional complex number image obtained and secondary channels two-dimensional complex number image, a pair pixel in two width images after registration is made to correspond to the same resolution element on ground, to ensure the coherence of the two width images that main channel and secondary channels receive;
Traditional method for registering images generally has cross correlation image registration method, based on the fast area cross-correlation method of spectrum computing, maximum spectrum method, phase differential image averaging wave function method etc., mainly be applicable to registration when land interferes survey high, radar altimeter provided by the invention is used for sea-level elevation and extracts, very high to the accuracy requirement of elevation extraction, method for registering images adopts cross correlation image registration method, in conjunction with the metrical information of spaceborne GPS device and star sensor, (metrical information comprises the attitude angle of the carrying platform of radar altimeter simultaneously, speed, acceleration, position, the information such as gps time), to improve registration accuracy.
Step 8, signal processing unit 3 carry out interference treatment to the main channel two-dimensional complex number image after image registration and secondary channels two-dimensional complex number image, obtain original interference phase diagram, interfere map of magnitudes and related coefficient figure;
The calculating of each the original interference phase place in original interference phase diagram comprises following steps:
By the pixel in the two-dimensional complex number image of main channel
get conjugation, then with the respective pixel in secondary channels two-dimensional complex number image
be multiplied, then the phase place after being multiplied taken out, original interference phase place can be obtained
(1)
The calculating of each the interference amplitude in map of magnitudes is interfered to comprise following steps:
By the pixel in the two-dimensional complex number image of main channel
get conjugation, then with the respective pixel in secondary channels two-dimensional complex number image
be multiplied, then the range value after being multiplied taken out, can obtain interfering map of magnitudes
, wherein m, n representative is the position of pixel;
The calculating of each related coefficient in related coefficient figure comprises following steps:
In formula,
represent main channel two-dimensional complex number image value,
represent secondary channels two-dimensional complex number image value, m, n representative be the position of pixel, M, N are for the window size parameter adopted when calculating is (when calculating related coefficient, for two dimensional image matrix, on matrix, several pixel value is relevant up and down with near it for the correlation coefficient value of certain position, need its pixel value up and down to substitute into during calculating to calculate, Here it is so-called window, M, N are the size of window).
Step 9, signal processing unit 3 pairs of original interference phase places go level land Phase Processing, that is, original interference phase place is cut the interferometric phase of reference planes;
Reference planes are height above sea level planes, and namely sea level elevation is the level land of 0m, and the interferometric phase of reference planes is that the height, antenna incident angle, wavelength, geometric relationship etc. of the carrying platform according to radar altimeter calculates.
Because main interference antenna 101 and auxiliary interference antenna 201 have the difference of geometric position, make the interferometric phase actual value of measurement target
change along with the position of target, interferometric phase actual value
it is not only height
function, and be target level ground distance
function, therefore carry out level land Phase Processing be convenient to follow-up phase unwrapping around;
Step 10, signal processing unit 3 carry out multiple look processing to the interferometric phase after past level land Phase Processing;
Multiple look processing is the Major Technology of the noise obviously weakening interferometric phase in the radar altimeter measurement of higher degree, sea is surveyed high, due to sea isomorphism within the specific limits, spatial resolution can reach km level, therefore can carry out a large amount of looking, multiple look processing obtains the method that the data of two passages in same marine site are divided by sub-aperture image process or frequency domain doppler bandwidth more
width looks subimage pair more, then to do after conjugate multiplication the corresponding double image element of every a pair in addition average, obtains the two-dimensional complex number image value of interferogram, namely
（2）
Wherein
represent and look number more,
with
represent the
depending on the respective pixel in image after a pair complex image corregistration.Right
carry out process and obtain interferometric phase
, wherein m, n representative is the position of pixel, the now two-dimensional complex number image value of interferogram
standard deviation depend on the related coefficient of two width images
size and look more look number
; And the related coefficient of main channel two-dimensional complex number image and secondary channels two-dimensional complex number image
be defined as:
（3）
Wherein Σ represents mathematics summation operation, f1 and f2 represents the two-dimensional complex number image value of major-minor two width images respectively, in actual estimated related coefficient
time, mathematical expectation can only be undertaken by space average, it must be noted that multiple look processing can not improve coherence, just can reduce interferometric phase
variance;
At the two-dimensional complex number image value of interferogram
distribution obey circle Gaussian statistics when, the standard deviation of interferometric phase can be obtained with related coefficient
with look number
increase and constantly decline, multiple look processing has preferably level and smooth Noise Reduction for interferometric phase, effectively can reduce the variance of interferometric phase, thus improves altimetry precision;
Step 11, signal processing unit 3 carry out the process of phase place noise reduction filtering to the interferometric phase after multiple look processing;
Due to system noise, baseline decorrelation, the impact of the factors such as antenna radiation pattern is inconsistent, be not be concerned with completely between main channel two-dimensional complex number image and secondary channels two-dimensional complex number image, can with the component (noise) of stochastic distribution in the phase place of interferogram, the interference of these noises can be estimated to bring serious error to ground elevation, also a large amount of residual points can be brought to make phase unwrapping below walk around Cheng Gengjia difficulty to interferogram, when requiring that measurement of higher degree precision reaches centimetre-sized when sea is surveyed high, also the process of phase place noise reduction filtering must be carried out to interferometric phase in the process that interferometric phase produces,
The process of phase place noise reduction filtering mainly utilizes the phase value of a SAR imaging neighborhood of pixels pixel to carry out smoothing pseudorange to this pixel, comprise the method such as mean filter and medium filtering, due to phase place with 2 π for mould, in the process of filtering, must be noted that the edge of interference fringe can not be done smoothly;
Step 12, signal processing unit 3 carry out phase unwrapping around process to the interferometric phase after the process of phase place noise reduction filtering;
Obtain reflecting that the true phase value of elevation information must add the integral multiple of 2 π to each phase value, by the interferometric phase after noise reduction filtering
carry out processing the process obtaining true phase value and be referred to as phase unwrapping around process;
Phase unwrapping is the key link in interference data processing procedure around process, the direct precision affecting Digital height model, conventional method has branch's method for cutting and least square method etc., mainly be applicable to registration when land interferes survey high, radar altimeter of the present invention is used for sea-level elevation and extracts, very high to the accuracy requirement of elevation extraction, phase unwrapping around on adopt Branch cut and Quality Map to instruct method, in conjunction with the metrical information of spaceborne GPS device and star sensor, (metrical information comprises the attitude angle of the carrying platform of radar altimeter simultaneously, speed, acceleration, position, the information such as gps time), to improve unwrapping precision.
Step 13, signal processing unit 3 carry out true phase calculating, that is, by adding the interferometric phase of reference planes through the interferometric phase of phase unwrapping after process, final true phase value φ is obtained, make the wave path-difference that phase value is corresponding real, to carry out the conversion of interferometric phase to height;
The interference map of magnitudes of step 14, signal processing unit 3 pairs of main channels and secondary channels and related coefficient figure carry out identifying water boy and classification process, extract the final true phase value φ in waters;
According to interference map of magnitudes and the related coefficient figure of main channel and secondary channels, by image procossing by the water area extraction such as ocean, surface water out, the waters extracted and land area are separated and highly resolves separately, avoid the interference being subject to land information in solution process, affect altimetry precision;
The reflectance signature on waters and land has difference in interference map of magnitudes, be 0.5 waters and land area can be made a distinction by setting threshold value, waters is regarded as in the continuum that interference amplitude is less than threshold value 0.5 namely, accuracy simultaneously in order to divide, can be further processed by related coefficient figure, waters and the land area difference on related coefficient figure is more obvious, the related coefficient in waters is less than the related coefficient of land area, the related coefficient in waters is less than 0.4, and the related coefficient of land area is greater than 0.8, the profile of waters and land area can divide and come according to these difference.
The final true phase value in the waters of extracting after step 15, signal processing unit 3 pairs of identifying water boy and classification process carries out altitude conversion and Geometry rectification process, obtains sea level height value h;
Unwrapping process can generate landform altitude information according to geometric relationship and coordinate conversion after adding that level land phase place obtains reflecting the final true phase value of landform altitude change;
First utilize relational expression (4) the guestimate height h between height and phase place, the carrying platform of radar altimeter provided in conjunction with GPS and the height in earth ellipsoid face, determine the ground coordinate of every bit;
（4）
Wherein, H be the carrying platform (such as: satellite) of radar altimeter highly, θ is the incident angle (being also the downwards angle of visibility of carrying platform relative to target P point (the ground arbitrary target points within the scope of the beam of radar) of radar altimeter) of main interference antenna 101
inclination angle formed by baseline and horizontal line, R1 is the distance of certain point of ground and main interference antenna 101, and B is base length, and λ is radar wavelength, and φ is the interferometric phase that last solution calculates, and antenna base length B immobilizes.
Fig. 3 is sea geometric model schematic diagram, major parameter is: podium level 900km, radar wavelength 0.022m, flying speed 7200m/s, antenna incident angle 3.2 ° etc., calculate the irradiation area size of antenna according to radar parameter and flight parameter, irradiation area is built to the geometric model on sea according to the PM spectrum on sea.Then stress and strain model is carried out to sea, radar return is calculated to each net point, the sea echo produced is through signal processing of the present invention, high result is surveyed on the sea obtained as shown in Figure 4, upper table represents the result curve of elevation carrection, and following table represents the graph of errors of elevation carrection, the deviation curve namely between measuring height value and theoretical level value, error mean is 0.025m, and altimetry precision is 0.036m.Known by emulating, little incident angle interference mode can carry out the extracted with high accuracy of sea level height, and altimetry precision reaches cm level.
The present invention takes little incident angle interference mode, and these two steps of multiple look processing, identifying water boy and classification are and the maximum different place of land InSAR elevation extraction method in traditional sense.
The precision that vertical accuracy of the present invention depends primarily on image registration, phase place noise reduction filtering, phase unwrapping reach around various algorithms such as the acquisitions with interference phase difference.
The invention provides the little incident angle of a kind of radar altimeter and interfere elevation extraction method when surveying high, this and the end of conventional radar altitude gauge, looked and observe different, thus can meet the demands such as, two-dimensional imaging high to the survey of ocean, sea ice ice shelf and Hydrology.Although elevation extraction method of the present invention and traditional large incident angle InSAR(synthetic aperture radar interferometry technology obtained for land elevation, Interferometric Synthetic Aperture Radar) elevation extraction method has certain similar, but both due to observation object different with application purpose, its realization Method and Technology feature also different.Traditional InSAR radar is mainly used in the measurement of land elevation, and vertical accuracy General Requirements is better than 10m, resolution element then General Requirements at 15m × below 15m.And survey the harshest high requirement in ocean is the altimetry precision that must meet centimetre-sized, new demand meets Small and Medium Sized observation, namely has larger observation swath and certain spatial resolution.Therefore the present invention carries out high-precision elevation acquisition in mesoscale resolution element, and its vertical accuracy reaches centimetre-sized, and resolution element is at 100m × more than 100m even more than 1km.The difference of observed object and survey high target, also determines little incident angle and interferes survey height to have certain difference with the elevation extraction method of InSAR in traditional sense.
Although content of the present invention has done detailed introduction by above preferred embodiment, will be appreciated that above-mentioned description should not be considered to limitation of the present invention.After those skilled in the art have read foregoing, for multiple amendment of the present invention and substitute will be all apparent.Therefore, protection scope of the present invention should be limited to the appended claims.
Claims (10)
1. a little incident angle Short baseline radar altimeter, is characterized in that, comprise:
Be separately positioned on main interference antenna (101) and the auxiliary interference antenna (201) at baseline two ends;
Be electrically connected the main transmit-receive switch circuit (102) of main interference antenna (101);
Be electrically connected the anti tr switch circuit (202) of auxiliary interference antenna (201);
Be electrically connected the main channel receiver module of main transmit-receive switch circuit (102);
Be electrically connected the secondary channels receiver module of anti tr switch circuit (202);
Be electrically connected the transmitter module of main transmit-receive switch circuit (102);
Be electrically connected the signal processing unit (3) of main channel receiver module and secondary channels receiver module;
Ranges of incidence angles when radar altitude measurement is high is for being more than or equal to 2 °, and be less than or equal to 6 °, base length scope is 2m ~ 15m.
2. little incident angle Short baseline radar altimeter as claimed in claim 1, is characterized in that,
Described main channel receiver module comprises the main channel receiver (103) being electrically connected main transmit-receive switch circuit (102), and is electrically connected the primary memory (104) of main channel receiver (103) and signal processing unit (3);
Described secondary channels receiver module comprises the secondary channels receiver (203) being electrically connected anti tr switch circuit (202), and is electrically connected the secondary store (204) of secondary channels receiver (203) and signal processing unit (3);
Described transmitter module comprises the transmitter (6) being electrically connected main transmit-receive switch circuit (102), and is electrically connected the Chirp generator (5) of transmitter (6), main channel receiver (103), secondary channels receiver (203) and control module (4).
3. little incident angle Short baseline radar altimeter as claimed in claim 2, is characterized in that,
FPGA circuit and high-speed a/d sample circuit is comprised in described main channel receiver (103);
FPGA circuit and high-speed a/d sample circuit is comprised in described secondary channels receiver (203).
4. a sea level height high-precision method for extracting for the little incident angle interference of radar altimeter, is characterized in that, comprise following steps:
The Chirp generator (5) of step 1, radar altimeter produces the Chirp signal of large bandwidth, and after transmitter (6), by main interference antenna (101) to be more than or equal to 2 °, the little incident angle being less than or equal to 6 ° is launched;
Step 2, main interference antenna (101) and auxiliary interference antenna (201) carry out coherent reception to echoed signal simultaneously, obtain main channel raw data and secondary channels raw data respectively;
Form main channel I road signal and Q road, main channel signal after FPGA circuit in step 3, main channel receiver (103) carries out quadrature demodulation to main channel raw data, the FPGA circuit in secondary channels receiver (203) forms secondary channels I road signal and secondary channels Q road signal after carrying out quadrature demodulation to secondary channels raw data;
High-speed a/d sample circuit in step 4, main channel receiver (103) carries out high speed analog-digital conversion sampling to main channel I road signal and Q road, main channel signal, sampled signal is stored in primary memory (104), high-speed a/d sample circuit in secondary channels receiver (203) carries out high speed analog-digital conversion sampling to secondary channels I road signal and secondary channels Q road signal, sampled signal is stored in secondary store (204);
Step 5, signal processing unit (3) carry out pre-filtering to the two ways of digital signals after primary memory (104) and the sampling of secondary store (204) high speed modulus;
Step 6, signal processing unit (3) carry out the process of SAR two-dimensional imaging to the digital signal after pre-filtering and obtain main channel two-dimensional complex number image and secondary channels two-dimensional complex number image;
Step 7, signal processing unit (3) carry out image registration to the main channel two-dimensional complex number image obtained and secondary channels two-dimensional complex number image, a pair pixel in two width images after registration is made to correspond to the same resolution element on ground, to ensure the coherence of the two width images that main channel and secondary channels receive;
Step 8, signal processing unit (3) carry out interference treatment to the main channel two-dimensional complex number image after image registration and secondary channels two-dimensional complex number image, obtain original interference phase diagram, interfere map of magnitudes and related coefficient figure;
Step 9, signal processing unit (3) go level land Phase Processing to original interference phase place, that is, original interference phase place is cut the interferometric phase of reference planes;
Step 10, signal processing unit (3) carry out multiple look processing to the interferometric phase after past level land Phase Processing;
Step 11, signal processing unit (3) carry out the process of phase place noise reduction filtering to the interferometric phase after multiple look processing;
Step 12, signal processing unit (3) carry out phase unwrapping around process to the interferometric phase after the process of phase place noise reduction filtering;
Step 13, signal processing unit (3) carry out true phase calculating, that is, by adding the interferometric phase of reference planes through the interferometric phase of phase unwrapping after process, obtain final true phase value φ;
Step 14, signal processing unit (3) carry out identifying water boy and classification process to the interference map of magnitudes of main channel and secondary channels and related coefficient figure, extract the final true phase value φ in waters;
Step 15, signal processing unit (3) the final true phase value to the waters of extracting after identifying water boy and classification process carries out altitude conversion and Geometry rectification process, obtains sea level height value h;
（4）
Wherein, H is the height of the carrying platform of radar altimeter, and θ is the incident angle of main interference antenna 101,
inclination angle formed by baseline and horizontal line, R1 is the distance of certain point of ground and main interference antenna 101, and B is base length, and λ is radar wavelength, and φ is the interferometric phase that last solution calculates, and antenna base length B immobilizes.
5. the sea level height high-precision method for extracting of the little incident angle interference of radar altimeter as claimed in claim 4, it is characterized in that, in described step 5, signal processing unit (3) arranges distance pulse pressure wave filter and Azimuth Compression wave filter according to grazing angle and Squint angle, carries out pre-filtering to the two ways of digital signals after high speed analog-digital conversion sampling.
6. the sea level height high-precision method for extracting of the little incident angle interference of radar altimeter as claimed in claim 4, is characterized in that, in described step 7, adopts cross correlation image registration method.
7. the sea level height high-precision method for extracting of the little incident angle interference of radar altimeter as claimed in claim 4, is characterized in that, in described step 8,
The calculating of each the original interference phase place in original interference phase diagram comprises following steps:
First by the pixel in a width two-dimensional complex number image
get conjugation, then with the respective pixel in another width two-dimensional complex number image
be multiplied, then the phase place after being multiplied taken out, original interference phase place can be obtained
(1);
The calculating of each the interference amplitude in map of magnitudes is interfered to comprise following steps:
By the pixel in the two-dimensional complex number image of main channel
get conjugation, then with the respective pixel in secondary channels two-dimensional complex number image
be multiplied, then the range value after being multiplied taken out, can obtain interfering map of magnitudes
, wherein m, n representative is the position of pixel;
The calculating of each related coefficient in related coefficient figure comprises following steps:
In formula,
represent main channel two-dimensional complex number image value,
represent secondary channels two-dimensional complex number image value, m, n representative be the position of pixel, M, the N window size parameter for adopting when calculating.
8. the sea level height high-precision method for extracting of the little incident angle interference of radar altimeter as claimed in claim 4, is characterized in that, in described step 10,
Multiple look processing obtains the method that the data of two passages in same marine site are divided by sub-aperture image process or frequency domain doppler bandwidth
width looks subimage pair more, then to do after conjugate multiplication the corresponding double image element of every a pair in addition average, obtains the two-dimensional complex number image value of interferogram, namely
（2）
Wherein
represent and look number more,
with
represent the
depending on the respective pixel in image after a pair complex image corregistration;
Right
carry out process and obtain interferometric phase
, wherein m, n representative is the position of pixel, the now two-dimensional complex number image value of interferogram
standard deviation depend on the related coefficient of two width images
size and look more look number
;
The related coefficient of main channel two-dimensional complex number image and secondary channels two-dimensional complex number image
be defined as:
（3）
Wherein Σ represents mathematics summation operation, and f1 represents the two-dimensional complex number image value of main channel two-dimensional complex number image, and f2 represents the two-dimensional complex number image value of secondary channels two-dimensional complex number image.
9. the sea level height high-precision method for extracting of the little incident angle interference of radar altimeter as claimed in claim 4, is characterized in that, in described step 12, phase unwrapping adopts Branch cut and Quality Map to instruct method around process.
10. the sea level height high-precision method for extracting of the little incident angle interference of radar altimeter as claimed in claim 4, it is characterized in that, in described step 14, the threshold value of setting interference amplitude is 0.5, interfere in map of magnitudes, waters is regarded as in the continuum that interference amplitude is less than 0.5 namely; Waters is regarded as in the region that related coefficient is less than 0.4.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201410630084.7A CN104316920A (en) | 2014-11-11 | 2014-11-11 | High-precision sea surface height extracting method of radar altimeter through small incidence angle interference |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201410630084.7A CN104316920A (en) | 2014-11-11 | 2014-11-11 | High-precision sea surface height extracting method of radar altimeter through small incidence angle interference |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN104316920A true CN104316920A (en) | 2015-01-28 |
Family
ID=52372173
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201410630084.7A Pending CN104316920A (en) | 2014-11-11 | 2014-11-11 | High-precision sea surface height extracting method of radar altimeter through small incidence angle interference |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN104316920A (en) |
Cited By (11)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN104574428A (en) * | 2015-02-04 | 2015-04-29 | 中国科学院遥感与数字地球研究所 | SAR image incident angle estimation method |
| CN104569938A (en) * | 2015-02-09 | 2015-04-29 | 中国科学院电子学研究所 | Synthetic aperture radar echo simulator |
| CN105005040A (en) * | 2015-07-02 | 2015-10-28 | 厦门大学 | Radar angle measurement method |
| CN106249234A (en) * | 2016-07-08 | 2016-12-21 | 中国科学院电子学研究所 | A kind of InSAR water body region interferometric phase unwrapping method |
| CN108981658A (en) * | 2018-07-09 | 2018-12-11 | 中国科学院国家空间科学中心 | A kind of river water level elevation extracting method based on spaceborne interference imaging altimeter |
| CN109581362A (en) * | 2018-11-28 | 2019-04-05 | 中国科学院国家空间科学中心 | Signal processing method of the synthetic aperture radar altimeter under variable pulse cluster mode |
| CN111505626A (en) * | 2020-04-26 | 2020-08-07 | 中国科学院国家空间科学中心 | Method for measuring two-dimensional terrain gradient by using bottom view differential interference |
| CN112083414A (en) * | 2020-09-18 | 2020-12-15 | 上海无线电设备研究所 | Double-frequency detection method for radar altimeter and satellite-borne equipment |
| CN113791395A (en) * | 2021-08-04 | 2021-12-14 | 中国人民解放军国防科技大学 | Simultaneous polarization measurement method based on orthogonal intermittent sampling modulation radar signals |
| CN114562991A (en) * | 2021-12-27 | 2022-05-31 | 北京控制工程研究所 | Relativistic astronomical effect navigator based on star sensor assistance and navigation method thereof |
| CN117213448A (en) * | 2023-11-07 | 2023-12-12 | 中国人民解放军国防科技大学 | Ocean secondary mesoscale frontal surface investigation method |
Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5175555A (en) * | 1991-03-15 | 1992-12-29 | Harris Corporation | Combined radar altimeter, radiometer sensor employing multiport feed horn having blended sidewall geometry |
| US6366835B1 (en) * | 1999-03-24 | 2002-04-02 | Bae Systems P1C | Height estimating apparatus |
| CN1985265A (en) * | 2004-07-15 | 2007-06-20 | 哈里公司 | Bare earth digital elevation model extraction for three-dimensional registration from topographical points |
| CN101236665A (en) * | 2008-02-29 | 2008-08-06 | 重庆交通大学 | Crossing ridge line design method based on digital height model DEM |
-
2014
- 2014-11-11 CN CN201410630084.7A patent/CN104316920A/en active Pending
Patent Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5175555A (en) * | 1991-03-15 | 1992-12-29 | Harris Corporation | Combined radar altimeter, radiometer sensor employing multiport feed horn having blended sidewall geometry |
| US6366835B1 (en) * | 1999-03-24 | 2002-04-02 | Bae Systems P1C | Height estimating apparatus |
| CN1985265A (en) * | 2004-07-15 | 2007-06-20 | 哈里公司 | Bare earth digital elevation model extraction for three-dimensional registration from topographical points |
| CN101236665A (en) * | 2008-02-29 | 2008-08-06 | 重庆交通大学 | Crossing ridge line design method based on digital height model DEM |
Non-Patent Citations (5)
| Title |
|---|
| 云日升等: ""相关系数图分类及其在干涉SAR二维相位展开中的应用"", 《电子与信息学报》 * |
| 张云华: ""宽刈幅海洋雷达高度计"", 《高科技与产业化》 * |
| 张云华等: ""三维成像雷达高度计机载原理样机及机载试验"", 《电子学报》 * |
| 曾斌: ""分布式卫星SAR慢动目标检测及关键技术研究"", 《中国优秀博硕士学位论文全文数据库（博士）信息科技辑》 * |
| 阎敬业: ""星载三维成像雷达高度计***设计与误差分析"", 《中国优秀博硕士学位论文全文数据库（博士）信息科技辑》 * |
Cited By (21)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN104574428B (en) * | 2015-02-04 | 2017-06-16 | 中国科学院遥感与数字地球研究所 | A kind of SAR image incidence angle evaluation method |
| CN104574428A (en) * | 2015-02-04 | 2015-04-29 | 中国科学院遥感与数字地球研究所 | SAR image incident angle estimation method |
| CN104569938A (en) * | 2015-02-09 | 2015-04-29 | 中国科学院电子学研究所 | Synthetic aperture radar echo simulator |
| CN104569938B (en) * | 2015-02-09 | 2017-03-08 | 中国科学院电子学研究所 | A kind of synthetic aperture radar echo simulation device |
| CN105005040A (en) * | 2015-07-02 | 2015-10-28 | 厦门大学 | Radar angle measurement method |
| CN105005040B (en) * | 2015-07-02 | 2017-05-03 | 厦门大学 | Radar angle measurement method |
| CN106249234B (en) * | 2016-07-08 | 2019-06-04 | 中国科学院电子学研究所 | A kind of InSAR water area interferometric phase unwrapping method |
| CN106249234A (en) * | 2016-07-08 | 2016-12-21 | 中国科学院电子学研究所 | A kind of InSAR water body region interferometric phase unwrapping method |
| CN108981658B (en) * | 2018-07-09 | 2019-11-19 | 中国科学院国家空间科学中心 | A kind of river water level elevation extracting method based on spaceborne interference imaging altimeter |
| CN108981658A (en) * | 2018-07-09 | 2018-12-11 | 中国科学院国家空间科学中心 | A kind of river water level elevation extracting method based on spaceborne interference imaging altimeter |
| CN109581362A (en) * | 2018-11-28 | 2019-04-05 | 中国科学院国家空间科学中心 | Signal processing method of the synthetic aperture radar altimeter under variable pulse cluster mode |
| CN111505626A (en) * | 2020-04-26 | 2020-08-07 | 中国科学院国家空间科学中心 | Method for measuring two-dimensional terrain gradient by using bottom view differential interference |
| CN111505626B (en) * | 2020-04-26 | 2022-07-26 | 中国科学院国家空间科学中心 | Method for measuring two-dimensional terrain gradient by using bottom view differential interference |
| CN112083414A (en) * | 2020-09-18 | 2020-12-15 | 上海无线电设备研究所 | Double-frequency detection method for radar altimeter and satellite-borne equipment |
| CN112083414B (en) * | 2020-09-18 | 2023-11-14 | 上海无线电设备研究所 | Dual-frequency detection method for radar altimeter and satellite-borne equipment |
| CN113791395A (en) * | 2021-08-04 | 2021-12-14 | 中国人民解放军国防科技大学 | Simultaneous polarization measurement method based on orthogonal intermittent sampling modulation radar signals |
| CN113791395B (en) * | 2021-08-04 | 2023-11-17 | 中国人民解放军国防科技大学 | Simultaneous polarization measurement method based on orthogonal intermittent sampling modulation radar signal |
| CN114562991A (en) * | 2021-12-27 | 2022-05-31 | 北京控制工程研究所 | Relativistic astronomical effect navigator based on star sensor assistance and navigation method thereof |
| CN114562991B (en) * | 2021-12-27 | 2024-02-09 | 北京控制工程研究所 | Relativistic astronomical effect navigator based on star sensor assistance and navigation method thereof |
| CN117213448A (en) * | 2023-11-07 | 2023-12-12 | 中国人民解放军国防科技大学 | Ocean secondary mesoscale frontal surface investigation method |
| CN117213448B (en) * | 2023-11-07 | 2024-01-30 | 中国人民解放军国防科技大学 | Ocean secondary mesoscale frontal surface investigation method |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN104316920A (en) | High-precision sea surface height extracting method of radar altimeter through small incidence angle interference | |
| Romeiser et al. | First analysis of TerraSAR-X along-track InSAR-derived current fields | |
| Gini et al. | Multibaseline cross-track SAR interferometry: A signal processing perspective | |
| CN101551455B (en) | 3D terrain imaging system of interferometric synthetic aperture radar and elevation mapping method thereof | |
| CN113340191B (en) | Time series interference SAR deformation quantity measuring method and SAR system | |
| CN101770027B (en) | Ground surface three-dimensional deformation monitoring method based on InSAR and GPS data fusion | |
| CN110888130A (en) | Coal mine area ground surface deformation monitoring method based on lifting rail time sequence InSAR | |
| CN105182339A (en) | Method for correcting environmental influences at slope deformation monitoring on the basis of corner reflector | |
| Liu et al. | Glacier elevation changes (2012–2016) of the Puruogangri Ice Field on the Tibetan Plateau derived from bi-temporal TanDEM-X InSAR data | |
| CN103698764A (en) | Interferometric synthetic aperture radar imaging method under sparse sampling condition | |
| CN104007439B (en) | Interferential circular SAR elevation estimation processing method | |
| Yu et al. | GNSS-based model-free sea surface height estimation in unknown sea state scenarios | |
| CN109116321A (en) | A kind of phase filtering method and height measurement method of spaceborne interference imaging altimeter | |
| CN106768179A (en) | The measuring method of the tidal level based on continuous operation GNSS stations signal-to-noise ratio data | |
| CN103344653A (en) | Real-time soil humidity measuring system and method based on double GPS receivers | |
| CN109631863A (en) | A kind of intertidal zone integration mapping method that vacant lot combines | |
| CN216411556U (en) | Synthetic aperture radar system based on time series interference deformation measurement | |
| Qiu et al. | Atmospheric phase screen correction in ground-based SAR with PS technique | |
| Mao et al. | Estimation and compensation of ionospheric phase delay for multi-aperture InSAR: An azimuth split-spectrum interferometry approach | |
| Marghany | DEM reconstruction of coastal geomorphology from DINSAR | |
| Marghany et al. | Robust of doppler centroid for mapping sea surface current by using radar satellite data | |
| Alonso-Arroyo et al. | Soil Moisture mapping using forward scattered GPS L1 signals | |
| Xia | CR-based SAR-interferometry for landslide monitoring | |
| Wang et al. | A high precision DEM extraction method based on InSAR data | |
| Marghany | Three dimensional coastline deformation from Insar Envisat Satellite data |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| C06 | Publication | ||
| PB01 | Publication | ||
| C10 | Entry into substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| RJ01 | Rejection of invention patent application after publication |
Application publication date: 20150128 |
|
| RJ01 | Rejection of invention patent application after publication |