WO2021036066A1 - 一种基于卫星编队的遥感系统及星座系统 - Google Patents

一种基于卫星编队的遥感系统及星座系统 Download PDF

Info

Publication number
WO2021036066A1
WO2021036066A1 PCT/CN2019/121956 CN2019121956W WO2021036066A1 WO 2021036066 A1 WO2021036066 A1 WO 2021036066A1 CN 2019121956 W CN2019121956 W CN 2019121956W WO 2021036066 A1 WO2021036066 A1 WO 2021036066A1
Authority
WO
WIPO (PCT)
Prior art keywords
baseline
star
auxiliary
satellite
auxiliary star
Prior art date
Application number
PCT/CN2019/121956
Other languages
English (en)
French (fr)
Inventor
杨峰
任维佳
杜志贵
陈险峰
Original Assignee
长沙天仪空间科技研究院有限公司
Priority date (The priority date 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 date listed.)
Filing date
Publication date
Priority claimed from CN201910788732.4A external-priority patent/CN110456350B/zh
Priority claimed from CN201910787398.0A external-priority patent/CN110488292B/zh
Application filed by 长沙天仪空间科技研究院有限公司 filed Critical 长沙天仪空间科技研究院有限公司
Priority to EP19943104.0A priority Critical patent/EP4020013A4/en
Priority to US17/637,744 priority patent/US11821980B2/en
Priority to CN201980086653.7A priority patent/CN113439220B/zh
Priority to JP2022512772A priority patent/JP7391429B2/ja
Publication of WO2021036066A1 publication Critical patent/WO2021036066A1/zh

Links

Images

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
    • G01S13/87—Combinations of radar systems, e.g. primary radar and secondary radar
    • 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
    • G01S13/89—Radar or analogous systems specially adapted for specific applications for mapping or imaging
    • G01S13/90—Radar or analogous systems specially adapted for specific applications for mapping or imaging using synthetic aperture techniques, e.g. synthetic aperture radar [SAR] techniques
    • G01S13/904—SAR modes
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B64—AIRCRAFT; AVIATION; COSMONAUTICS
    • B64G—COSMONAUTICS; VEHICLES OR EQUIPMENT THEREFOR
    • B64G1/00—Cosmonautic vehicles
    • B64G1/10—Artificial satellites; Systems of such satellites; Interplanetary vehicles
    • B64G1/1021—Earth observation satellites
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B64—AIRCRAFT; AVIATION; COSMONAUTICS
    • B64G—COSMONAUTICS; VEHICLES OR EQUIPMENT THEREFOR
    • B64G1/00—Cosmonautic vehicles
    • B64G1/10—Artificial satellites; Systems of such satellites; Interplanetary vehicles
    • B64G1/1021—Earth observation satellites
    • B64G1/1035—Earth observation satellites using radar for mapping, surveying or detection, e.g. of intelligence
    • 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
    • G01S13/89—Radar or analogous systems specially adapted for specific applications for mapping or imaging
    • G01S13/90—Radar or analogous systems specially adapted for specific applications for mapping or imaging using synthetic aperture techniques, e.g. synthetic aperture radar [SAR] techniques
    • G01S13/9004—SAR image acquisition techniques
    • G01S13/9011—SAR image acquisition techniques with frequency domain processing of the SAR signals in azimuth
    • 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
    • G01S13/89—Radar or analogous systems specially adapted for specific applications for mapping or imaging
    • G01S13/90—Radar or analogous systems specially adapted for specific applications for mapping or imaging using synthetic aperture techniques, e.g. synthetic aperture radar [SAR] techniques
    • G01S13/9021—SAR image post-processing techniques
    • G01S13/9023—SAR image post-processing techniques combined with interferometric techniques
    • 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
    • G01S13/89—Radar or analogous systems specially adapted for specific applications for mapping or imaging
    • G01S13/90—Radar or analogous systems specially adapted for specific applications for mapping or imaging using synthetic aperture techniques, e.g. synthetic aperture radar [SAR] techniques
    • G01S13/9021—SAR image post-processing techniques
    • G01S13/9029—SAR image post-processing techniques specially adapted for moving target detection within a single SAR image or within multiple SAR images taken at the same time
    • 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
    • G01S13/89—Radar or analogous systems specially adapted for specific applications for mapping or imaging
    • G01S13/90—Radar or analogous systems specially adapted for specific applications for mapping or imaging using synthetic aperture techniques, e.g. synthetic aperture radar [SAR] techniques
    • G01S13/904—SAR modes
    • G01S13/9058—Bistatic or multistatic SAR
    • 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
    • G01S19/00—Satellite radio beacon positioning systems; Determining position, velocity or attitude using signals transmitted by such systems
    • G01S19/01—Satellite radio beacon positioning systems transmitting time-stamped messages, e.g. GPS [Global Positioning System], GLONASS [Global Orbiting Navigation Satellite System] or GALILEO
    • G01S19/13—Receivers
    • G01S19/24—Acquisition or tracking or demodulation of signals transmitted by the system
    • G01S19/25—Acquisition or tracking or demodulation of signals transmitted by the system involving aiding data received from a cooperating element, e.g. assisted GPS
    • G01S19/258—Acquisition or tracking or demodulation of signals transmitted by the system involving aiding data received from a cooperating element, e.g. assisted GPS relating to the satellite constellation, e.g. almanac, ephemeris data, lists of satellites in view
    • 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
    • G01S7/00—Details of systems according to groups G01S13/00, G01S15/00, G01S17/00
    • G01S7/02—Details of systems according to groups G01S13/00, G01S15/00, G01S17/00 of systems according to group G01S13/00
    • G01S7/28—Details of pulse systems
    • G01S7/285—Receivers
    • G01S7/288—Coherent receivers

Definitions

  • the present invention relates to the field of remote sensing technology, in particular to a remote sensing system and a constellation system based on satellite formation.
  • the satellite remote sensing system refers to the active/passive imaging observation of the earth carried by the satellite platform with sensors, and the acquisition of various features of the earth in the form of digital images.
  • the satellite equipped with synthetic aperture radar adopts microwave active detection method, through the pulse compression in the range and the synthetic aperture technology in the azimuth, it can penetrate clouds, rain, fog, sand and dust storms, etc., and has the ability to work all-weather and all-day. It can achieve high-resolution wide-format imaging of the ground, which is the most effective data acquisition method for areas with cloudy and rainy all year round.
  • synthetic aperture radar satellites can obtain complex images of the observation area, which contain both intensity information and phase information.
  • phase information of the radar complex image data can be extracted to invert the terrain and small changes of the surface. This information makes synthetic aperture radar satellites have unique application value in the fields of land resources, earthquake, geology, disaster prevention and mitigation, agriculture, forestry, hydrology, surveying and mapping and military.
  • the Chinese patent document with the publication number CN108120981A discloses a shallow water deep radar remote sensing detection method, which includes: acquiring a multi-scene SAR remote sensing image of the area to be detected, wherein the multi-scene SAR remote sensing image includes q single-scene SAR remote sensing images.
  • each single-scene SAR remote sensing image contains the image characteristics of the waves in the area to be detected from the deep water area to the shallow water area.
  • each single-scene SAR remote sensing image Calculate each single-scene SAR remote sensing image to obtain the shallow water depth detection results in the shallow water area;
  • the shallow water depth detection results obtained from each single-scene SAR remote sensing image are respectively tidal correction;
  • the corrected shallow water depth detection results are formed element by element according to predetermined rules to form a one-dimensional shallow sea depth array containing q elements, and the Kalman filter algorithm is used to correct
  • the last element value in each group of shallow water depth array after filtering of each group of shallow water depth array is used as the depth of the shallow water area.
  • This patent uses a single satellite carrying radar to perform synthetic aperture radar imaging, and uses multiple single-scene SAR remote sensing images to achieve large-area, near-real-time shallow sea terrain detection, especially when the water color level is high, cloudy and rainy, and ships cannot enter. Shallow sea area.
  • the Chinese patent document with the publication number CN108053416A discloses a maximum oil storage extraction system based on a single satellite image, including a satellite remote sensing image browsing module, an image sub-region segmentation module, an automatic boundary point capture module, and an oil tank shadow measurement system.
  • High module and oil storage calculation module among them, the satellite remote sensing image browsing module is used to obtain human-computer interaction information during satellite remote sensing image operation; the image sub-region segmentation module is used to extract the contour edge of the oil tank target to facilitate the selection of key points; The boundary point automatically captures the auxiliary selection of the key points on the arc edge of the module; the oil tank shadow height measurement module is used to calculate the height of the oil tank based on the shadow information of the oil tank.
  • This patent is based on a single satellite image to accurately extract the height of the oil tank, which effectively avoids the calculation error caused by manually determining the arc point of the same name, and greatly improves the extraction speed of the oil tank height.
  • the above patent uses a single SAR satellite remote sensing imaging, which has limited terrain features, limited resolution, and limited surveying width.
  • the height information of the ground in a single satellite image is insufficient, and the height of the oil tank extracted is not accurate enough.
  • the image resolution is limited, and the obtained contours, shadows and other information are not accurate enough.
  • insufficiently accurate image information even if the calculation error caused by manually determining the arc point with the same name is avoided, accurate height information cannot be obtained.
  • the use of multiple single-scene SAR remote sensing images to realize underwater terrain detection in shallow water cannot avoid the time synchronization problem of multiple single-scene SAR remote sensing images, that is, the multiple single-scene SAR remote sensing images obtained under a single satellite are not continuous in time. , The azimuth is discontinuous, and the water depth information contained therein is the information at different times, which cannot guarantee the real-time nature of terrain detection under shallow water.
  • the resolution of the image and the mapping width are contradictory. It is impossible to maintain a high resolution while imaging a wide area. Therefore, in the case of imaging a large area of shallow water, it can only maintain a relatively high resolution. Low-resolution imaging is not conducive to underground exploration of shallow water.
  • Distributed synthetic aperture radar systems based on satellite formations or constellations have receiving antennas on different satellites and separate transceiver platforms. Therefore, they not only have a long inter-satellite space baseline, but also can be achieved by combining multiple low-resolution wide-range Synthetic aperture radar images are combined to improve the spatial resolution to obtain high-definition, wide-format images.
  • the distributed synthetic aperture radar satellite system can generate at least two complex images, and due to the existence of the inter-satellite space baseline, it can provide more terrain phase information during the interference processing of the two complex images, which is high-precision, wide-range, three-dimensional Provide conditions for the realization of remote sensing imaging of the scene.
  • the Chinese patent document with the publication number CN108557114A discloses a distributed remote sensing satellite, including a service star and six remote sensing unit stars, and the service star and remote sensing unit stars can adopt a distributed formation mode or a synthetic aperture combination. mode.
  • This patent realizes the rapid design, development and in-orbit application of modular satellites through distributed satellite technology, uses low-cost satellite systems to achieve high-performance ground remote sensing systems, and autonomously splices in orbit to form synthetic aperture imaging to improve spatial resolution and maximize Use space resources.
  • the Chinese patent document with the publication number CN104297751B discloses a method for fusion of primary and secondary SAR graphics of a distributed satellite SAR system.
  • the specific steps are: Doppler spectrum envelope correction; radar geometric image registration; terrain phase inversion Performing; SAR image maximum contrast method to estimate registration error and residual phase deviation; primary and secondary SAR image fine registration and phase deviation correction; Doppler spectrum stitching.
  • this patent can effectively image the main and auxiliary SAR images to improve the azimuth resolution and meet high-quality interference synthesis. Performance requirements for aperture radar processing.
  • the distributed remote sensing satellites do not take into account the time synchronization between the formation satellites, and cannot guarantee that the two satellites cover the same area on the ground at the same time, resulting in the degradation of the interference performance of the two complex images, or even the inability to form interference.
  • time asynchrony also causes the remote sensing satellites to be unable to obtain the temporal and spatial characteristics of ground area changes based on time information.
  • the phase difference obtained is the main value of the phase after the unknown integer period between [- ⁇ , ⁇ ] is wound, and the phase needs to be expanded. The time unsynchronization between the two satellites will lead to errors in the phase unfolding, and the phase information contains the altitude information of the terrain, which makes the remote sensing system unable to obtain accurate three-dimensional scene images.
  • the Chinese patent document with the publication number CN107395309 discloses a high-precision relative ranging and time synchronization method based on inter-satellite links.
  • the method includes: The satellite carrier frequency standard is used as the reference to establish the inter-satellite link, and the speed measurement information and the constant error are incorporated into the dynamic error model; the two satellites A and B respectively capture, track and demodulate the received signals of the other party in the receiving time slot.
  • the information frame is recovered, and the local pseudorange is calculated when the other party measures the time slot to send the epoch; finally, the A satellite and the B satellite respectively embed the corrected pseudorange into the local baseband data and send it to the other party, and the two satellites use it independently.
  • this patent only considers time synchronization, and does not consider the interference phase error caused by the frequency drift of the receiving device on the satellite platform, nor does it consider the inconsistency of antenna angles, resulting in the beam not covering the same area.
  • the satellite formation synthetic aperture radar system provides high-precision, wide-range, three-dimensional imaging, time, frequency, and space synchronization are used to compensate for phase unwrapping errors to improve terrain altimetry.
  • the accuracy of the ground area changes based on time, frequency and space synchronization to obtain the temporal and spatial characteristics of the ground area.
  • the present invention provides a remote sensing system, especially a remote sensing system based on satellite formation, which is characterized in that it includes a primary satellite, a first secondary satellite, and a second secondary satellite with a SAR system as a payload.
  • the first auxiliary star and the second auxiliary star fly around the main star, and the main star is located on the long axis of the trajectory of the first auxiliary star and the second auxiliary star to form a first with the same tangent track baseline component.
  • Spatial baseline A and second spatial baseline B are examples of Spatial baseline A and second spatial baseline B.
  • the main satellite uses an imaging sensing device and a synchronization device as payloads.
  • the synchronization device forms a first spatial baseline A and a second spatial baseline B in a time sequence based on the synchronized time, frequency, and space.
  • the sensing device obtains the temporal and spatial characteristics of the ground area change according to the first spatial baseline A and the second spatial baseline B.
  • a third auxiliary star flying in formation before and after the main star is arranged outside of the movement trajectory of the first auxiliary star and the second auxiliary star, and the third auxiliary star with the payload of the imaging sensor device and the synchronization device is arranged, and the second auxiliary star
  • the three auxiliary stars are located on the adjacent orbits of the main star, so that the third auxiliary star has a long track baseline C and a short track baseline D relative to the main star, wherein the imaging sensor device is based on the
  • the first spatial baseline A and the second spatial baseline B are combined with the short-cut trajectory baseline D and the long-along trajectory baseline C to perform optimal interference baseline processing to obtain terrain elevation information and terrain elevation information while performing high-definition wide-format imaging. Moving target speed information.
  • the imaging sensing device is also provided with the satellite attitude parameters that can measure the satellite attitude parameters of the main satellite, the first satellite, the second satellite, and the third satellite in real time, and can achieve precise orbit determination to obtain the high precision.
  • the imaging sensor device can also obtain a priori information of the ground target area through the measurement device, and adjust the main star, third auxiliary star, first auxiliary star, and second satellite based on the latitude information of the ground target area.
  • the antenna angle of the imaging sensor device on the second satellite is to maintain the same elevation ambiguity, thereby improving the consistency of ground elevation measurement accuracy in different latitude regions.
  • the antenna angles of the imaging sensor devices on the main star, the third auxiliary star, the first auxiliary star, and the second auxiliary star are adjusted With a second elevation ambiguity that remains the same and is different from the first elevation ambiguity, the SAR system is imaged with at least two different elevation ambiguities.
  • the first spatial baseline A, the second spatial baseline B, the short-cut trajectory baseline D, and the long-along trajectory baseline C form a time sequence
  • the imaging sensor device obtains the time-based change information of the speed of the moving target based on the time-series tangent along the track, and obtains the time-based change information of the ground elevation based on the time-series tangent of the track.
  • the orbit parameters of the first auxiliary star and the second auxiliary star are based on the effective baselines of the first space baseline A and the second space baseline B.
  • the length is compared with the limit length of the effective baseline of the tangent track to obtain by adjusting the short semi-axis of the flight trajectories of the first auxiliary star and the second auxiliary star, and the orbit parameters of the third auxiliary star are based on the azimuth.
  • the synchronization device includes at least a time synchronization module, a frequency synchronization module, and a space synchronization module, wherein the time synchronization module is configured to generate timing pulse signals carried by each satellite based on the simultaneous triggering of power-on and pass the inter-satellite frequency Synchronize the pulse to obtain the frequency difference between the satellites to achieve time synchronization.
  • the frequency synchronization module in the synchronization device is configured to use a chirp signal as a synchronization pulse to exchange the primary satellite with the first secondary satellite or the second secondary satellite or the third secondary satellite in a periodic manner.
  • the synchronization pulse signal is processed to obtain the phase difference caused by the frequency source on the satellite, so as to perform phase compensation to achieve frequency synchronization.
  • the space synchronization module in the synchronization device is configured to: based on the orientation of the imaging sensor device on the main star to the ground target area and the direction of the first auxiliary star or the second auxiliary star or the third auxiliary star
  • the attitude of the satellite is such that the imaging sensor device on the first auxiliary star or the second auxiliary star or the third auxiliary star points to the same ground target area to complete the space synchronization.
  • the present invention also provides a spaceborne SAR constellation system, which is characterized by comprising: a main star using the SAR system as a payload, and at least a pair of first auxiliary stars and second auxiliary stars flying around the main star, wherein: The first auxiliary star and the second auxiliary star fly around the main star, and the main star is located on the long axis of the trajectory of the first auxiliary star and the second auxiliary star to form a first auxiliary star with the same tangent track baseline component.
  • a spatial baseline A and a second spatial baseline B where,
  • the first auxiliary star and the second auxiliary star form a passive and stable configuration in such a manner that the main star is centered symmetrically so that the first auxiliary star forms a first spatial baseline A relative to the main star, and the second auxiliary star forms a first spatial baseline A relative to the main star.
  • the star forms a second space baseline B with respect to the host star, wherein the first space baseline A and the second space baseline B have the same length and opposite phases.
  • the spaceborne SAR constellation system further includes a third auxiliary star,
  • the third auxiliary star flies forward and backward in formation with the first main star on the orbits of the first auxiliary star and the second auxiliary star and adjacent to the main star, so as to grow relative to the main star
  • the SAR system based on the first space baseline A and the second space baseline B generates a length greater than the short-cut trajectory baseline D and a long vertical baseline and a length less than the The short horizontal baseline of the long trajectory baseline C, combined with the short-cut trajectory baseline D and the long trajectory baseline C for optimal interference signal processing to improve the accuracy of terrain height measurement while imaging with high resolution and wide swaths And range.
  • the main star after obtaining the orbital parameters of the main star, the third auxiliary star, the first auxiliary star, and the second auxiliary star, the main star obtains the SAR radar antenna attitude parameters through a measuring device to compare the main star and the third auxiliary star.
  • the first auxiliary star and the second auxiliary star realize precise orbit determination to obtain the high-precision first space baseline A, second space baseline B, horizontal baseline C, and short-cut trajectory baseline D,
  • the measurement device includes at least a GPS receiver for attitude measurement, and the GPS receiver performs the following steps:
  • Preprocessing the original data mainly including ephemeris data decoding and data synchronization;
  • an inter-satellite baseline vector is obtained, and the attitude parameters of the SAR radar antenna are obtained by solving the inter-satellite baseline vector.
  • the present invention also provides a satellite remote sensing system, which is characterized in that a main satellite with a SAR system as a payload, a third auxiliary star, and at least a pair of first auxiliary stars and second auxiliary stars flying around the main star, wherein: After the main star obtains the attitude parameters of the SAR radar antenna, the GPS receiver is connected to the GPS constellation based on the orbit parameters of the main star, the third auxiliary star, the first auxiliary star, and the second auxiliary star, at least Acquire priori information of solar and moon perturbation, solar pressure perturbation, and atmospheric drag perturbation.
  • the GPS receiver is based on the attitude of the SAR radar antenna
  • the parameters and the orbit determination result obtained by the orbital disturbance model of the constellation system are used to obtain the first space baseline A, the second space baseline B, the long-track trajectory baseline C, and the short-cut trajectory baseline D.
  • the present invention provides a remote sensing system based on satellite formation, which adopts a formation structure in which the main star is located on the long axis of the first auxiliary star and the second auxiliary star's trajectory, and the third auxiliary star and the main star fly back and forth.
  • the type forms the first space baseline A and the second space baseline B with the same length and phase-reversed tangent track baseline components, which can avoid the first space baseline A and the second space baseline B due to the along-track baseline and the tangent track baseline.
  • the baseline coupling causes the phase of the obtained ground height information to be mixed with the radial velocity information, which can improve the accuracy of the topographic survey height.
  • the present invention obtains time-series along-track baselines and cut-to-track baselines based on time, frequency, and space synchronization by the synchronization device to obtain time, frequency and other synchronization information to correct the received signals, and utilizes long and short cuts.
  • the trace baseline is phase unwound, and the phase unwrapping accuracy is improved to further improve the accuracy of terrain height measurement, so as to obtain the small changes in the elevation and speed in the ground area over time.
  • a remote sensing system based on satellite formation includes a primary satellite, a first secondary satellite, and a second secondary satellite with an imaging sensing device and a synchronization device as payloads.
  • the first auxiliary star and the second auxiliary star fly around the main star, and the main star is located on the long axis of the trajectory of the first auxiliary star and the second auxiliary star to form a first auxiliary star with the same tangent track baseline component.
  • the imaging sensing device forms a first spatial baseline A and a second spatial baseline B of a time sequence based on time, frequency, and space synchronization by the synchronization device to acquire the temporal and spatial characteristics of the ground area change.
  • a third auxiliary star flying in formation with the main star and taking the imaging sensor device and the synchronization device as the payload is arranged outside the movement trajectory of the first auxiliary star and the second auxiliary star.
  • the third auxiliary star is located on an orbit adjacent to the main star, so that the third auxiliary star has a long track baseline C and a short-cut track baseline D relative to the main star.
  • the imaging sensor device is based on the first spatial baseline A and the second spatial baseline B, and combines the short-cut track baseline D and the long-along track baseline C to perform optimal interference baseline processing to perform optimal interference baseline processing in high-definition and wide-range Obtain terrain elevation information and moving target speed information at the same time of imaging.
  • the first spatial baseline A, the second spatial baseline B, the short-cut trajectory baseline D, and the long-along trajectory baseline C form a time sequence The along-track baseline and the cut-track baseline.
  • the imaging sensor device obtains information about the change of the speed of the moving target with time based on the time series along the tangent line of the track.
  • the imaging sensor device obtains information on the change of ground elevation over time based on the time series of the cut track baseline.
  • the orbit parameters of the first auxiliary star and the second auxiliary star are based on the effective baselines of the first space baseline A and the second space baseline B.
  • the length is compared with the limit length of the effective baseline of the tangent trajectory to be obtained by adjusting the short semi-axis of the flight trajectories of the first auxiliary star and the second auxiliary star.
  • the orbit parameters of the third auxiliary star are obtained based on the requirements of spatial sampling required for azimuth Doppler defuzzification and the requirements of Doppler defuzzification accuracy.
  • the synchronization device includes at least a time synchronization module, a frequency synchronization module, and a space synchronization module.
  • the time synchronization module is configured to generate timing pulse signals carried by each satellite based on the start-up and trigger at the same time, and obtain the frequency difference between the satellites through the inter-satellite frequency synchronization pulse to achieve time synchronization.
  • the frequency synchronization module is configured to use a chirp signal as a synchronization pulse to periodically exchange synchronization pulse signals on the primary satellite and the first secondary satellite or the second secondary satellite or the third secondary satellite Process to obtain the phase difference caused by the frequency source on the satellite, so as to perform phase compensation to achieve frequency synchronization.
  • the space synchronization module is configured to: based on the orientation of the imaging sensing device on the main satellite to the ground target area and the satellite attitude of the first auxiliary star or the second auxiliary star or the third auxiliary star, The imaging sensor device on the first auxiliary star or the second auxiliary star or the third auxiliary star points to the same ground target area to complete spatial synchronization.
  • the imaging sensing device is also provided with the satellite attitude parameters that can measure the satellite attitude parameters of the main satellite, the first satellite, the second satellite, and the third satellite in real time, and can achieve precise orbit determination to obtain the high precision.
  • the imaging sensor device can also obtain a priori information of the ground target area through the measurement device.
  • the imaging sensing device adjusts the antenna angles of the imaging sensing devices on the main star, the third auxiliary star, the first auxiliary star, and the second auxiliary star based on the latitude information of the ground target area to maintain the same elevation ambiguity, Thereby improving the consistency of ground elevation measurement accuracy in different latitude regions.
  • the antenna angles of the imaging sensor devices on the main star, the third auxiliary star, the first auxiliary star, and the second auxiliary star are adjusted With a second elevation ambiguity that remains the same and is different from the first elevation ambiguity, the SAR system is imaged with at least two different elevation ambiguities.
  • the present invention provides a spaceborne SAR constellation system, which adopts the first auxiliary star and the second auxiliary star to symmetrically orbit the main star as the center to form a passive and stable orbit configuration.
  • the second satellite and the second satellite can respectively form a first space baseline A and a second space baseline B with the same length and opposite phases at any time during the orbital period, and then solve them based on the first space baseline A and the second space baseline B.
  • the long vertical baseline containing terrain height information and the short horizontal baseline containing velocity information are obtained by coupling, and combined with the long-track trajectory baseline C and the short-cut trajectory baseline D formed between the third auxiliary star and the main star, the SAR system can be based on The long vertical baseline, the short-cut track baseline D, the long-along track baseline C and the short horizontal baseline perform optimal interference signal processing to improve the accuracy and range of terrain height measurement while imaging with high resolution and wide swath.
  • a spaceborne SAR constellation system includes: a main star with a SAR system as a payload, a third auxiliary star, and at least a pair of first auxiliary stars and second auxiliary stars flying around the main star.
  • the first auxiliary star and the second auxiliary star form a passive stable configuration in such a manner that they are centered symmetrically with respect to the main star, so that the first auxiliary star forms a first spatial baseline A relative to the main star.
  • the second auxiliary star forms a second spatial baseline B with respect to the main star.
  • the first spatial baseline A and the second spatial baseline B have the same length and opposite phases.
  • the third auxiliary star flies forward and backward in formation with the first main star on the orbits of the first auxiliary star and the second auxiliary star and adjacent to the main star, so as to grow relative to the main star Along the trajectory baseline C and the short-cut trajectory baseline D.
  • the SAR system generates, based on the first spatial baseline A and the second spatial baseline B, a vertical baseline with a length greater than the short-cut trajectory baseline D and a horizontal baseline with a length smaller than the long-along trajectory baseline C, and combined
  • the short-cut trajectory baseline D and the long-along trajectory baseline C perform optimal interference signal processing to improve the accuracy and range of terrain height measurement while imaging with high resolution and wide swath.
  • the orbit parameters of the third auxiliary star are obtained by the following steps: according to mission requirements, the orbit parameters of the main star are obtained, wherein the eccentricity of the orbit of the main star is 0; the length of the first auxiliary star and the second auxiliary star The semi-axis, orbital inclination, and ascension of the ascending node are the same as those of the main star, and the short semi-major axis and semi-major axis of the first auxiliary star and the second auxiliary star's flight trajectory are calculated by the Hill equation, wherein the first auxiliary star The initial design value of the short semi-axis of the flight trajectory of the star and the second auxiliary star is the baseline requirement of the mission; according to the phase difference between the flight trajectories of the first auxiliary star and the second auxiliary star, the argument of perigee and the angle of anomaly are determined ; According to the orbital parameters of all satellites currently calculated, calculate the effective vertical baseline length of the first space baseline A and the second space baseline B within an orbital period
  • the main star after obtaining the orbital parameters of the main star, the third auxiliary star, the first auxiliary star, and the second auxiliary star, obtains the SAR radar antenna attitude parameters through a measuring device to compare the main star and the third auxiliary star.
  • the first auxiliary star and the second auxiliary star realize precise orbit determination to obtain the high-precision first space baseline A, second space baseline B, horizontal baseline C, and short-cut trajectory baseline D.
  • the measuring device at least includes a GPS receiver for attitude measurement.
  • the GPS receiver performs the following steps: preprocessing the original data, mainly including ephemeris data decoding and data synchronization; obtaining the position parameters of the SAR radar antenna through a differential positioning algorithm; using the position parameters of the SAR radar antenna Obtain the initial value of the ambiguity of the whole week, use the Kalman filter and recursive search method to solve the accurate value of the ambiguity of the whole week, and use the carrier phase to obtain the precise coordinates; use to obtain the precise coordinate values to obtain the inter-satellite baseline vector, and The attitude parameters of the SAR radar antenna are obtained by solving the inter-satellite baseline vector.
  • the GPS receiver is based on the orbital parameters of the main star, the third auxiliary star, the first auxiliary star, and the second auxiliary star and correlates with the GPS constellation.
  • the GPS receiver is based on the The attitude parameters of the SAR radar antenna and the orbit determination results obtained by the orbital disturbance model of the constellation system are used to obtain the first space baseline A, the second space baseline B, the long-along track baseline C and the short-cut track baseline D.
  • the master star before the master star obtains a priori information through the GPS constellation, the master star performs time synchronization to avoid the influence of clock errors.
  • the main star, the third auxiliary star, the first auxiliary star, and the second auxiliary star all include a synchronization device.
  • the synchronization device at least includes a time synchronization component.
  • the time synchronization component is configured to generate timing pulse signals carried by each satellite based on the start-up and trigger at the same time, and obtain the frequency difference between the satellites through the inter-satellite frequency synchronization pulse to achieve time synchronization.
  • the synchronization device further includes a frequency synchronization component.
  • the frequency synchronization component is configured to: use a linear time-varying frequency signal as a synchronization pulse to interrupt the acquisition of any two satellite-borne SAR information in a periodic manner, and process the exchanged synchronization pulse signals to obtain any two-satellite frequency source The resulting phase difference. Perform phase compensation on the SAR based on the phase difference to achieve frequency synchronization.
  • the first space baseline A, the second space Baseline B, horizontal baseline C, and short-cut track baseline D form the horizontal and vertical baselines of the time series.
  • the primary satellite acquires the latitude information of the ground observation area according to the prior information of the GPS constellation, and adjusts the third auxiliary satellite.
  • the antenna angles of the satellite, the first auxiliary star, and the second auxiliary star maintain the same elevation ambiguity to improve the consistency of the elevation measurement accuracy in different latitude regions.
  • a spaceborne SAR imaging method comprising: using a main star with a SAR system as a payload, a third auxiliary star, and at least a pair of first auxiliary stars and second auxiliary stars flying around the main star Constellation for imaging.
  • the first auxiliary star and the second auxiliary star form a passive and stable configuration in a centrally symmetrical manner with respect to the main star, so that the first auxiliary star and the second auxiliary star form the same length relative to the main star.
  • a first spatial baseline A and a second spatial baseline B that are opposite in phase.
  • the third auxiliary star flies forward and backward in formation with the first main star on an orbit outside the flight orbits of the first auxiliary star and the second auxiliary star and adjacent to the first main star.
  • the third auxiliary star has a long track baseline C and a short track baseline D relative to the first main star.
  • the SAR system generates a longer vertical baseline and a shorter horizontal baseline based on the first spatial baseline A and the second spatial baseline B, and combines the short-cut track baseline D and the long-along track baseline C for optimization.
  • Excellent interference signal processing to improve the accuracy and range of topographic surveying while imaging with high resolution and wide swath.
  • the main star obtains prior information by connecting with the GPS constellation through the synchronization device, the main star obtains the latitude information of the ground observation area based on the prior information of the GPS constellation to adjust the main star, third auxiliary star,
  • the antenna angles of the SAR system on the first auxiliary satellite and the second auxiliary satellite maintain the same elevation ambiguity, thereby improving the consistency of elevation measurement accuracy in different latitude regions.
  • the third auxiliary star, the first auxiliary star, and the second auxiliary star maintain the same first elevation ambiguity imaging, when the terrain height of the ground observation area obtained based on the prior information changes
  • the amplitude is large, adjust the antenna angles of the SAR system on the main star, the third auxiliary star, the first auxiliary star, and the second auxiliary star to maintain the same second elevation ambiguity that is different from the first elevation ambiguity, so that The SAR system images with at least two different elevation ambiguities.
  • Time and space synchronization can ensure that the main beams of the two satellites cover the same area on the ground at the same time, and can ensure that the time windows of the two satellites receive echo signals are synchronized; frequency synchronization can reduce the interference phase error caused by the frequency drift of the two satellites;
  • the long trajectory baseline C, the first space baseline A and the second space baseline B contain radial velocity information, which can provide conditions for moving target detection, and the long trajectory baseline C and the short trajectory baseline can also provide
  • the azimuth provides the required spatial sampling for Doppler deblurring to compensate for the lack of time sampling caused by the low azimuth repetition frequency, thereby providing conditions for the azimuth deblurring to achieve high-definition and wide imaging;
  • the phase unwrapping based on the long-cut trajectory baseline components in the first space baseline A and the second space baseline B may be wrongly unwrapped, so the present invention is adopted.
  • the time series along the track baseline and the cut track baseline are used to obtain synchronization information such as time and frequency to correct the received signal, and the long and short cut track baselines are used for phase unwrapping to improve the phase unwrapping accuracy to further improve
  • the accuracy of terrain height measurement can obtain small changes in elevation and speed over time in the ground area.
  • Figure 1 is a schematic diagram of a preferred imaging sensor device and synchronization device of the present invention.
  • Figure 2 is a geometric schematic diagram of a preferred satellite formation of the present invention.
  • imaging sensor device 400 synchronization device
  • Measuring device 410 Time synchronization module
  • Frequency synchronization module 430 Spatial synchronization module
  • A The first spatial baseline B: The second spatial baseline
  • Each “module” in the present invention may be one or more of a dedicated integrated chip, a server, and a server group.
  • the module of the present invention describes any kind of hardware, software, or combination of software and hardware, which can perform the functions associated with the "module”.
  • the present invention discloses a remote sensing imaging method, it can also be a satellite-based remote sensing imaging method, it can also be a distributed synthetic aperture radar remote sensing imaging method, or it can be a satellite formation-based remote sensing imaging method.
  • the remote sensing imaging method can be implemented by the system of the present invention and/or other replaceable components.
  • the system of the present method is realized by using various components in the system of the present invention.
  • the whole and/or part of the content of the preferred implementation manners of other embodiments may be used as a supplement to this embodiment.
  • the imaging method includes a primary satellite 100, a first secondary satellite 200, and a second secondary satellite 201 with the imaging sensing device 300 and the synchronization device 400 as payloads.
  • the first auxiliary star 200 and the second auxiliary star 201 fly around the main star 100 and the main star 100 is located on the long axis of the trajectory of the first auxiliary star 200 and the second auxiliary star 201 to form a first space with the same tangent track baseline component Baseline A and second spatial baseline B.
  • the imaging sensing device 300 forms a first spatial baseline A and a second spatial baseline B of a time sequence based on time, frequency, and space synchronization according to the synchronization device 400 to acquire the temporal and spatial characteristics of the ground area change.
  • the imaging sensor device 300 at least includes an imaging sensor capable of actively or passively acquiring ground information.
  • the imaging sensor can be radar, laser, etc. capable of imaging.
  • the imaging sensor may be a sensor capable of imaging in a synthetic aperture manner, for example, synthetic aperture radar, synthetic aperture lidar, and the like.
  • the first auxiliary star 200 and the second auxiliary star 201 take the main star 100 as the orbiting center, and use the Hill equation to design them into a passive and stable configuration that does not require fuel consumption. As shown in FIG. 2, the trajectories of the first auxiliary star 200 and the second auxiliary star 201 are elliptical trajectories under the description of the Hill equation.
  • the present invention can enable the first auxiliary star 200, the second auxiliary star 201 and the main star 100 to maintain relative spatial positions, so that a stable first spatial baseline A and a second spatial baseline B can be obtained.
  • the first spatial baseline A and the second spatial baseline B change periodically with the rotation period of the elliptical configuration, so that the first spatial baseline A and the second spatial baseline B contain speed information and terrain height information.
  • the imaging devices 300 on the main star 100, the first auxiliary star 200, and the second auxiliary star 201 receive the echo signals sent by the main star 100 to the ground target.
  • the synthetic aperture radar imaging sensor in the imaging device 300 obtains multiple synthetic aperture radar images of the ground target by means of low-azimuth re-sampling, and stitches multiple synthetic aperture radar images to form high-definition and wide synthetic aperture radar images.
  • the first spatial baseline A and the second spatial baseline B contain phases of velocity information and terrain height information, providing conditions for high-resolution, wide-range, and three-dimensional imaging.
  • the first spatial baseline A and the second spatial baseline B have the same length and phase-reversed tangent track baseline components because the main star 100 is located on the long axis. Therefore, for example, the method of differential processing can be used to obtain only the terrain height.
  • At least the beneficial technical effect that the present invention can achieve by adopting this method is: it can prevent the first space baseline A and the second space baseline B from being mixed with the radial velocity in the phase of the ground height information obtained due to the coupling of the along-track baseline and the tangent track baseline. Information, which can improve the accuracy of topographic survey height.
  • the first spatial baseline A and the second spatial baseline B can be synchronized in time, frequency and space based on the synchronization device 400 to obtain the first spatial baseline A and the second spatial baseline B of the time series, thereby obtaining the time series along the route.
  • Track baseline and cut track baseline refers to that the time-series cut-to-track baseline contains information about ground elevation changes with time, and the time-series along-track base contains information about the speed of the target changing with time.
  • the present invention can obtain small changes in the height of crops, forests, etc. over time. At the same time, small changes in the height of plains, mountains, etc. over time can also be obtained.
  • the growth and development status of crops and their changes can be obtained in advance, which can be compared with the data of last year, multi-year average, and the same period of a specified year, and crop growth differences can be obtained in real time, that is, spatial distribution and height distribution.
  • Change status so that the proportion of different growth grades in paddy field, dry land, arable land and main crops can be counted by region.
  • the present invention can also use the radial velocity along the trajectory baseline in the time series to achieve target extraction and velocity estimation.
  • the difference in the coherence coefficients of the echo signals of seawater and sea ice can be used in seawater to realize the separation of sea ice and seawater, and the radial velocity information of sea ice and seawater can be obtained through the time series along the track baseline. The corresponding speed estimate.
  • the synchronization device 400 at least includes a time synchronization module 410, a frequency synchronization module 420, and a space synchronization module 430.
  • the time synchronization module 410 is configured to generate timing pulse signals carried by each satellite based on the simultaneous triggering of power-on, and obtain the frequency difference between the satellites through the inter-satellite frequency synchronization pulse to achieve time synchronization.
  • the start-up trigger timing pulse signal can be realized by the GPS second pulse.
  • the signal emitted by the host satellite 100 forms an echo signal after being reflected on the ground.
  • the echo signal is processed by the imaging sensor device 300 after passing through the synchronization device 400.
  • the frequency synchronization module 420 is configured to use the chirp signal as the synchronization pulse to exchange the synchronization pulse signal processing on the primary satellite 100 and the first secondary satellite 200 or the second secondary satellite 201 or the third secondary satellite 101 in a periodic manner.
  • the phase compensation is performed to achieve frequency synchronization.
  • the frequency linear time-varying signal is a chirp signal.
  • the primary satellite 100, the third secondary satellite 101, the first secondary satellite 200, and the second secondary satellite 201 are all equipped with 6 synchronized horn antennas to provide quasi-omnidirectional beam coverage, ensuring near real-time and omni-directional frequency synchronization pulse reception.
  • the main star 100 sends synchronization pulses to the third auxiliary star 101, the first auxiliary star 200, and the second auxiliary star 201, respectively. Due to the characteristic that the frequency of the chirp signal changes linearly with time, the synthetic aperture radar data acquisition of the host satellite 100 will be periodically interrupted.
  • the synchronization pulse will be transmitted from the main antenna of the imaging sensor device 300 of the main star 100 to the horn dedicated for synchronization on the third auxiliary star 101 and/or the first auxiliary star 200 and/or the second auxiliary star 201 Antenna, the third auxiliary satellite 101 and/or the first auxiliary satellite 200 and/or the second auxiliary satellite 201 record the pulse and then transmit a short synchronization pulse to the main satellite 100, and obtain the relative position of the main satellite 100 by processing the exchanged synchronization pulse signal
  • the phase difference caused by the frequency source on the other auxiliary satellites will be compensated for the corresponding phase when the imaging sensor device 300 on each satellite is imaging, so as to complete the frequency synchronization.
  • the frequency of the frequency source on the satellite can also be considered as a constant, and the frequency difference can be extracted from the linear part of the phase difference of the synchronization signal to complete time synchronization.
  • the space synchronization module 430 is configured to: based on the orientation of the imaging sensing device 300 on the main satellite 100 to the ground target area and the satellite attitude of the first auxiliary star 200 or the second auxiliary star 201 or the third auxiliary star 101 so that The imaging sensor device 300 on the first auxiliary star 200 or the second auxiliary star 201 or the third auxiliary star 101 points to the same ground target area to complete spatial synchronization.
  • the antenna of the imaging sensor device 300 on the main star 100 points to the imaging area in a front-view mode
  • the first auxiliary star 200, the second auxiliary star 201, and the third auxiliary star 101 can point to the imaging area with a small angle squint. Observe ground target imaging in a way.
  • time and space synchronization can ensure that the main beams of two satellites cover the same area on the ground at the same time, and can ensure that the time windows of the two satellites receive echo signals are synchronized;
  • frequency synchronization can reduce the interference phase error caused by the frequency drift of the two satellites.
  • a third auxiliary star 101 with the imaging sensor device 300 and the synchronization device 400 as payloads is arranged outside the movement trajectory of the first auxiliary star 200 and the second auxiliary star 201 to fly in formation with the main star 100 back and forth.
  • the third auxiliary star 101 is located in an orbit adjacent to the main star 100, so that the third auxiliary star 101 forms a long-track trajectory baseline C and a short-cut trajectory baseline D relative to the main star 100.
  • the imaging sensing device 300 is based on the first spatial baseline A and the second spatial baseline B, and combines the short-cut trajectory baseline D and the long-along trajectory baseline C to perform optimal interference baseline processing to obtain terrain while high-definition wide-range imaging Elevation information and moving target speed information.
  • the imaging sensor device 300 generates a long-cut trajectory baseline with a length greater than the short-cut trajectory baseline D and a short-along trajectory baseline with a length less than the long-along trajectory baseline C based on the first spatial baseline A and the second spatial baseline B , And combine the short-cut trajectory baseline D and the long-along trajectory baseline C for optimal interference signal processing to improve the accuracy and range of terrain height measurement while imaging with high resolution and wide swath.
  • the distance between the orbit of the third auxiliary star 101 and the orbit of the main star 100 is at least 120 m, and the distance between the orbit of the third auxiliary star 101 and the orbit of the main star 100 is kept fixed, as shown in FIG. 2.
  • the space baseline formed by the third auxiliary star 101 relative to the main star 100 can be decomposed to obtain a short-cut track baseline D and a long-along track baseline C.
  • the short-cut trajectory baseline D of the present invention is always determined and remains unchanged during the phase when the third auxiliary star 101 and the main star 100 are in orbit, which can be used to accurately determine the third auxiliary star 101 and the main star 100.
  • Orbit and baseline measurements provide prior conditions and error analysis.
  • the imaging sensor devices 300 on the main star 100, the third auxiliary star 101, the first auxiliary star 200, and the second auxiliary star 201 receive the echo signals sent by the main star 100 to the ground target.
  • the imaging sensor device 300 obtains multiple synthetic aperture radar images of a ground target by using a low-azimuth re-sampling method. Since the imaging sensor device 300 uses a low-azimuth re-sampling method to acquire images, it will cause azimuth Doppler blur.
  • the azimuth Doppler frequency is proportional to the sine of the azimuth instantaneous oblique viewing angle and has a one-to-one correspondence.
  • the azimuth Doppler spectrum is aliased and blurred, and its azimuth Doppler frequency is no longer proportional to the sine of the azimuth instantaneous oblique viewing angle, but is composed of multiple directions
  • the azimuth instantaneous oblique angle of view energy is mixed.
  • the process of azimuth Doppler defuzzification is for each Doppler frequency, when the energy of multiple pointing azimuths instantaneous oblique viewing angles is mixed, the energy of the instantaneous oblique viewing angle of specific pointing azimuths is extracted one by one, and finally the non-blurring is reconstructed through splicing. Blurred Doppler spectrum.
  • the present invention can at least achieve at least the following beneficial technical effects in this manner: first, the long-along track baseline C and the short-along track baseline contain radial velocity information, which can provide conditions for moving target detection; second, the long-along track The track baseline C and the short-track track baseline can also provide the spatial sampling needed for the azimuth to Doppler defuzzification, thereby making up for the lack of time sampling caused by the low azimuth repetition frequency, thereby providing conditions for the azimuth doppler ambiguity solution .
  • the existence of the first space baseline A, the second space baseline B, and the physical baseline formed by the third auxiliary star 101 relative to the main star 100 will introduce a space-variable vector.
  • the multi-baseline interference processing of baseline D can obtain the phase information introduced by the cut-track baseline in each Doppler frequency.
  • the present invention can at least achieve at least the following beneficial technical effects in this manner: First, based on the obtained phase information, phase compensation is performed before Doppler ambiguity is resolved, so as to improve the terrain measurement altitude while the Doppler ambiguity resolution is satisfied. Range; Second, the multi-baseline interference processing of the long-cut trajectory baseline and the short-cut trajectory baseline D can also improve the accuracy of terrain height measurement.
  • the orbital parameters of the first auxiliary satellite 20 and the second auxiliary satellite 201 are based on the length of the effective baseline of the tangent trajectory of the first space baseline A and the second space baseline B.
  • the limit length of the effective baseline of the trajectory is compared and obtained by adjusting the short semi-axis of the flight trajectory of the first auxiliary star 20 and the second auxiliary star 201.
  • the orbit parameters of the third auxiliary satellite 101 are obtained based on the requirements of spatial sampling required for azimuth Doppler defuzzification and the requirements of Doppler defuzzification accuracy.
  • the orbital parameters of the third auxiliary star 101 are obtained by the following steps: according to mission requirements, the orbital parameters of the main star 100 are obtained, where the eccentricity of the main star's orbit is 0; the length of the first auxiliary star 200 and the second auxiliary star 201 The semi-axis, orbital inclination and ascension of the ascending node are the same as those of the main star 100, and the short semi-major axis and semi-major axis of the first auxiliary star 200 and the second auxiliary star 201 are calculated by the Hill equation.
  • the first auxiliary star The initial design value of the short semi-axis of the flight trajectory of 200 and the second auxiliary star 201 is the baseline requirement of the mission; according to the phase difference between the flight trajectories of the first auxiliary star 200 and the second auxiliary star 201, the argument of perigee and the perigee are determined Angle; According to the orbital parameters of all satellites currently calculated, calculate the effective tangent track baseline length of the first space baseline A and the second space baseline B in one orbit period, and judge whether it is less than the limit baseline length of the tangent track effective baseline ; If it is not less than the limit baseline length of the effective baseline of the tangent track, adjust the short semi-axis of the flight trajectory of the first auxiliary star 200 and the second auxiliary star 201 until the first space baseline A and the second space baseline B The length of the effective tangent track baseline meets the requirements; according to the orbital parameters of the main star 100, the first auxiliary star 200 and the second auxiliary star 201 obtained in the above steps, the long-a
  • the eccentricity is 0.
  • the orbit type, orbit height and other parameters combined with Hill equations to obtain the 6 numbers of the orbit of the host star, namely the semi-major axis of the orbit, the orbit eccentricity, and the orbit eccentricity.
  • the Hill equation describing the motion of the auxiliary star is:
  • the origin of the coordinate system in the formula is defined as the main star 100, the main star is along the earth orbiting satellite, the x-axis points to the flight direction of the reference satellite, the y-axis is perpendicular to the orbit plane of the main star 100, and the z-axis points away from the center of the earth to the main star 100.
  • ⁇ k identifies the initial position of the k-th auxiliary star in the elliptical orbit configuration
  • T represents the orbit period.
  • the main star 100 is the center of the first auxiliary star 200 and the second auxiliary star 201, so B is zero.
  • the relative movement of the first auxiliary star 200 and the second auxiliary star 201 is an elliptical trajectory in the XZ plane, and the semi-major axis along the speed direction X is twice the semi-minor axis perpendicular to the speed direction Z.
  • the relative movement of the first auxiliary star 200 and the second auxiliary star 201 makes independent sinusoidal motions on the y-axis.
  • the first auxiliary star 200 and the second auxiliary star 201 rotate slowly in an elliptical configuration centered on the main star 100.
  • the first auxiliary star 200, the second auxiliary star 201, and the main star 100 are all in the same orbital plane, so the orbital inclination angle and ascension of the ascending node of the three are the same.
  • the baseline is the initial design value of the short semi-axis of the elliptical trajectory formed by the formation flight. Since the short semi-axis of the elliptical trajectory of the relative motion of the formation flight is only related to the semi-major axis and the eccentricity of the satellite, when the semi-major axis has been determined, the first auxiliary star 200 and the second auxiliary star 201 are determined by the short semi-axis. The eccentricity.
  • the main star 100 is located on the long axis of the trajectory of the first auxiliary star 200 and the second auxiliary star 201, the argument of perigee and the angle of anomaly of the first auxiliary star 200 and the second auxiliary star 201 can be determined.
  • the first auxiliary star 200 and the second auxiliary star 201 in one orbit period can be calculated respectively relative to the first auxiliary star 100.
  • the space sampling requirements for Doppler defuzzification so that the length of the effective baseline of the cut track and the length of the effective baseline along the track should be less than the corresponding limit baseline length.
  • the limit baseline length of the effective baseline of the cut trajectory :
  • ⁇ is the working wavelength of the imaging sensor device 300
  • ⁇ is the viewing angle
  • Is the oblique angle of view
  • ⁇ is the angle between the line of each satellite's centroid and the horizontal plane, that is, the baseline inclination
  • ⁇ is the terrain slope
  • R represents the average slant distance between the two satellites forming the baseline and the ground target.
  • p a and p r represent the distance and azimuth resolution.
  • R may be obtained according to formula 4, wherein the track 100 of a semi-major axis of the main star, R e radius of the earth:
  • p r and p a formula 5 may be obtained according to, wherein, c denotes the speed of light as the signal bandwidth, B w, D represents the azimuth antenna size:
  • the orbit design parameters of the main star 100, the first auxiliary star 200, and the second auxiliary star 201 are completed based on the above conditions to calculate the orbit parameters of the third auxiliary star 101.
  • the orbit of the third auxiliary star 101 and the orbit of the main star 100 maintain a fixed distance.
  • the third auxiliary star 101 and the main star 100 are arranged in a forward and backward formation flying manner.
  • the forward and backward distance between the third auxiliary star 101 and the main star 100 meets the limit baseline length of the effective baseline along the track.
  • the present invention can at least achieve the following beneficial technical effects: First, the first auxiliary star 200, the second auxiliary star 201, and the main star 100 fly in a co-orbital plane, the elliptical space configuration is passive and stable, and the power system is only in orbit.
  • the orbit of the third auxiliary satellite 101 is similar to the orbit of the main satellite 100 and adopts front and rear formation flying, which can ensure that the formation satellites can meet the azimuth Doppler solution at any time Blur the along-track baseline required by the space sampling required to improve the imaging efficiency of the system;
  • the spatial configuration formed by the third auxiliary star 101, the first auxiliary star 200, the second auxiliary star 201, and the main star 100 is a common Orbital surface configuration, which is easy to maintain and has low fuel consumption;
  • the formation configuration of the present invention can form a stable baseline and baseline inclination, and is suitable for interferometric synthetic aperture radar imaging;
  • the formation configuration of the present invention The model can form multiple effective tangent track baselines and multiple effective along-track baselines at any time, and multiple effective tangent track baselines and multiple effective along-track baselines meet the requirements of multi-baseline interference processing; sixth, this The effective tangent track baseline formed at any time by the invented formation configuration meets the
  • the first space baseline A, the second space baseline B, the short-cut trajectory baseline D, and the long-track trajectory baseline C form a time-series along trajectory Baseline and cut track baseline.
  • the imaging sensor device 300 acquires information about the change of the speed of the moving target over time based on the time-series tangent along the track.
  • the imaging sensor device 300 obtains information on changes in ground elevation over time based on the time-series cut-to-track baseline.
  • the phase difference obtained from the interferogram is the phase after an unknown integer period winding between [- ⁇ , ⁇ ]
  • the main value, the winding phase needs to be restored to the true phase difference, that is, phase unwrapping.
  • the imaging sensor device 300 obtains synchronization information such as time and frequency based on the time series along the track baseline and the cut track baseline, so as to correct the received signal.
  • the imaging sensor device 300 performs phase compensation based on the corrected information, and uses the short-cut track baseline to phase unwrap the long-cut track baseline, thereby further improving the accuracy of terrain height measurement.
  • the present invention can at least achieve the following beneficial technical effects: due to the low measurement accuracy of the short-cut track baseline D, the phase unwrapping of the long-cut track baseline may be wrongly unwrapped.
  • the time series along the track baseline and the cut track baseline obtain synchronization information such as time and frequency to correct the received signal, and use the long and short cut track baselines for phase unwrapping to improve the phase unwrapping accuracy to further improve the terrain height measurement
  • the accuracy of this can be used to obtain small changes in elevation and speed in the ground area.
  • the imaging sensor device 300 is also provided with satellite attitude parameters that can measure the satellite attitude parameters of the main satellite 100, the first auxiliary satellite 200, the second auxiliary star 201, and the third auxiliary star 101 in real time, and can achieve precise orbit determination to obtain high precision.
  • the measuring device 310 at least includes a GPS receiver for attitude measurement.
  • the GPS receiver performs the following steps: preprocess the original data, mainly including ephemeris data decoding and data synchronization; obtain the position parameters of the antenna of the imaging sensor device 300 through the differential positioning algorithm; use the position of the antenna of the imaging sensor device 300
  • the parameter obtains the initial value of the ambiguity of the whole week, the accurate value of the ambiguity of the whole week is solved by the method of Kalman filtering and recursive search, and the precise coordinates are obtained by the carrier phase; the baseline vector between satellites is obtained by obtaining the precise coordinate values,
  • the attitude parameters of the antenna of the imaging sensor device 300 are obtained by solving the inter-satellite baseline vector.
  • the GPS receiver is a high-precision dual-frequency GPS receiver.
  • a GPS occultation receiver is integrated in the high-precision dual-frequency GPS receiver.
  • the GPS receiver preprocesses the received raw data, performs single-point positioning coordinate calculation, and then calculates the mobile coordinate station coordinates through code double-difference positioning to obtain the rough position coordinates of the antenna of the imaging sensor device 300.
  • a carrier phase method with a wavelength of centimeter level and a range measurement error of millimeter level is required to measure the distance. Since the carrier signal is a periodic sine signal, when the measured distance is greater than the wavelength, there will be ambiguity in the whole circle.
  • the GPS receiver obtains the initial value of the ambiguity of the whole week based on the rough position coordinates, and solves the accurate value of the ambiguity of the whole week by the method of Kalman filtering and recursive search.
  • the GPS receiver is based on the orbital parameters of the main satellite 100, the third auxiliary star 101, the first auxiliary star 200, and the second auxiliary star 201 and correlates with the GPS constellation.
  • the GPS receiver is based on imaging sensor device 300
  • the antenna attitude parameters and the orbit determination results obtained from the formation's orbital disturbance model are obtained by the differential carrier phase measurement method to obtain the first space baseline A, the second space baseline B, the long-track baseline C and the short-cut track baseline D.
  • the influence of the aspherical perturbation of the earth, the perturbation of sunlight pressure, and the perturbation of atmospheric resistance on the satellite is not negligible, and can be estimated as model noise combined with prior information.
  • the orbital perturbation model is a linear accumulation of accelerations caused by aspherical earth perturbation, sunlight pressure perturbation, and atmospheric drag perturbation that affect satellite motion.
  • the differential carrier phase measurement method is to differentiate between the path delays of the two satellites and the orbit determination error caused by the algorithm to eliminate most of the common error components of the two satellites, and the corresponding baseline vector is obtained by the difference of the orbit determination results of the two satellites.
  • the GPS receiver can eliminate most of the orbit determination errors shared by the two satellites, and then through algorithm optimization and establishment of the orbital disturbance model for corresponding compensation, it can accurately measure the baseline and Satellite attitude parameters.
  • the imaging sensor device 300 can also obtain a priori information of the ground target area through the measurement device 310.
  • the imaging sensor device 300 adjusts the antenna angles of the imaging sensor device 300 on the main star 100, the third auxiliary star 101, the first auxiliary star 200, and the second auxiliary star 201 based on the latitude information of the ground target area to maintain the same elevation blur
  • the elevation ambiguity reflects the sensitivity of the change of the interference phase to the elevation change. When the tangent track baseline is longer, the elevation ambiguity is smaller, and the interference phase is more sensitive to elevation changes.
  • the interference phase is not sensitive to elevation changes, which reduces the accuracy of terrain height measurement.
  • the elevation ambiguity is proportional to the sine of the instantaneous oblique viewing angle of the azimuth, and due to the rotation of the earth, the effective baseline obtained by projecting the spatial baseline onto the ground has different lengths at different latitudes.
  • the antenna of the imaging sensor device 300 The angle can adjust the height ambiguity.
  • the present invention can at least achieve the following beneficial technical effects: the main satellite 100 can obtain the latitude information of the ground observation area according to the prior information of the GPS constellation, and adjust the antenna angle to maintain the same elevation ambiguity, thereby improving the elevation measurement in different latitude regions. Consistency of accuracy.
  • the imaging sensor devices 300 on the main star 100, the third auxiliary star 101, the first auxiliary star 200, and the second auxiliary star 201 are adjusted.
  • the antenna angle of is maintained at the same second elevation ambiguity that is different from the first elevation ambiguity, so that the SAR system is imaged with at least two different elevation ambiguities.
  • the third auxiliary star 101, the first auxiliary star 200, and the second auxiliary star 201 are maintained at the same first elevation ambiguity imaging, when imaging is obtained based on the prior information
  • the second elevation ambiguity of the first elevation ambiguity causes the imaging sensor device 300 to image with at least two different elevation ambiguities.
  • the main phase value will be discontinuous and the phase unwrapping error will be too large.
  • the imaging sensor device 300 performs imaging with different elevation ambiguities based on adjusting the antenna angle to check the consistency of the two imaging phase expansions and the difference of the same imaging area, thereby reducing the phase expansion error.
  • the present invention can at least achieve the following beneficial technical effects: when imaging steep areas and other areas with large terrain undulations, imaging with different elevation ambiguities can reduce phase unwrapping errors, improve relative accuracy, and thereby increase topographic survey height The precision.
  • module as used herein describes any kind of hardware, software, or combination of software and hardware that can perform the functions associated with the “module”.

Landscapes

  • Engineering & Computer Science (AREA)
  • Remote Sensing (AREA)
  • Radar, Positioning & Navigation (AREA)
  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Computer Networks & Wireless Communication (AREA)
  • Electromagnetism (AREA)
  • Astronomy & Astrophysics (AREA)
  • Aviation & Aerospace Engineering (AREA)
  • Signal Processing (AREA)
  • Evolutionary Computation (AREA)
  • Radar Systems Or Details Thereof (AREA)
  • Navigation (AREA)

Abstract

一种基于卫星编队的遥感系统，包括以SAR系统为有效载荷的主星(100)、第一辅星(200)和第二辅星(201)，第一辅星(200)和第二辅星(201)围绕主星(100)飞行且主星(100)位于第一辅星(200)和第二辅星(201)的运动轨迹的长轴上以形成具有相同切航迹基线分量的第一空间基线(A)和第二空间基线(B)，该系统能够在基于卫星编队提供高精细、宽幅、三维成像的情况下，通过时间、频率以及空间同步来获取地面区域变化的时空特征。

Description

一种基于卫星编队的遥感系统及星座系统 技术领域
本发明涉及遥感技术领域，尤其涉及一种基于卫星编队的遥感系统及星座系统。
背景技术
卫星遥感系统是指卫星平台搭载传感器对地进行主/被动的成像观测，以数字图像的方式获取地球多方面特征信息。搭载合成孔径雷达的卫星采用微波有源探测的方式，通过距离向的脉冲压缩和方位向的合成孔径技术，可穿透云、雨、雾、沙尘暴等，具备全天候、全天时的工作能力，能实现对地高分辨宽幅成像，是常年多云雨地区最有效的数据获取方式。
区别于光学遥感，合成孔径雷达卫星可获取观测区域的复影像，即同时包含强度信息和相位信息。通过合成孔径干涉测量技术，可提取雷达复影像数据的相位信息反演地形和地表微小变化信息。这些信息使得合成孔径雷达卫星在国土资源、地震、地质、防灾减灾、农业、林业、水文、测绘与军事等领域有独特的应用价值。
例如，公开号为CN108120981A的中国专利文献公开了一种浅海水深雷达遥感探测方法，该方法包括：获取待探测区域的多景SAR遥感图像，其中，多景SAR遥感图像包括q个单景SAR遥感图像，每个单景SAR遥感图像均包含待探测区域内海浪由深水海区传至浅水海区的图像特征，对每个单景SAR遥感图像进行计算，分别得到浅水海区的浅海水深探测结果；对通过各个单景SAR遥感图像得到的浅海水深探测结果分别进行潮汐校正；对校正后的浅海水深探测结果逐元素根据预定的规则组成包含q个元素的一维浅海水深数组，通过卡尔曼滤波器算法对每组浅海水深数组进行滤波后的每组浅海水深数组中最后一个元素数值作为浅水海区的深度。该专利利用单颗载有雷达的卫星进行合成孔径雷达成像，利用多个单景SAR遥感图像实现大面积、近实时浅海水下地形探测，尤其在水色级次较高，多云多雨以及船只无法进入的浅海区域。
例如，公开号为CN108053416A的中国专利文献公开了一种基于单幅卫星图像的最大储油量提取系统，包括卫星遥感图像浏览模块、图像子区域分割模块、边界点自动 捕捉模块、油罐阴影测高模块和储油量计算模块；其中，卫星遥感图像浏览模块用于获取卫星遥感图像操作时的人机交互信息；图像子区域分割模块用于提取油罐目标的轮廓边缘，方便关键点选取；边界点自动捕捉模块弧边上的关键点的辅助选取；油罐阴影测高模块用于基于油罐阴影信息计算油罐的高度。该专利基于单幅的卫星图像进行油罐高度的精确提取，有效避免了人工方式确定同名弧点带来的计算误差，大幅提高了油罐高度的提取速度。
但是，以上专利采用单颗SAR卫星遥感成像，其获得的地形特征有限、分辨率有限、测绘宽度有限。例如，单幅卫星图像中地面的高度信息不足，提取得到的油罐高度不够精确。而且图像分辨率有限，得到的轮廓、阴影等信息也不够精确，采用不够精确的图像信息，即使避免了人工方式确定同名弧点带来的计算误差，也无法得到精确的高度信息。而采用多个单景SAR遥感图像来实现浅海水下地形探测，无法避免多个单景SAR遥感图像的时间同步问题，即在单颗卫星下得到的多个单景SAR遥感图像是时间不连续、方位向不连续的，其包含的水深信息是不同时刻下的信息，无法保证浅海水下地形探测的实时性。另外，对于单颗合成孔径雷达卫星而言，图像的分辨率和测绘宽度是矛盾的，无法在宽幅成像的同时保持高分辨率，因此在大面积浅海水成像的情况下，只能保持较低的分辨率成像，不利于浅海水的地下探测。基于卫星编队或星座的分布式合成孔径雷达系统，在不同的卫星上设置接收天线，其收发平台分置，因此不仅具有较长的星间空间基线，还可以通过将多个低分辨率宽幅的合成孔径雷达图像结合以提高空间分辨率来获取高精细度、宽幅的图像。分布式合成孔径雷达卫星系统至少能够生成两幅复影像，并且由于星间空间基线的存在，在两幅复影像干涉处理时能够提供更多的地形相位信息，为高精细度、宽幅、三维场景的遥感成像的实现提供条件。
例如，公开号为CN108557114A的中国专利文献公开了一种分布式遥感卫星，包括一颗服务星和六颗遥感单元星，且所述服务星和遥感单元星可采用分布式编队模式或合成孔径组合模式。该专利通过分布式卫星技术，实现模块化卫星快速设计、研制和在轨应用，利用低成本卫星系统实现高性能对地遥感系统，在轨自主拼接构成合成孔径成像来提高空间分辨率，最大化利用空间资源。
例如，公开号为CN104297751B的中国专利文献公开了一种分布式卫星SAR系统的主辅SAR图形融合方法，其具体步骤为：多普勒谱包络校正；雷达几何法图像配准；地形相位反演；SAR图像最大对比度法估计配准误差及残留相位偏差；主辅SAR图像精配准及相位偏差校正；多普勒谱拼接。该专利在长沿航迹基线分布式卫星SAR系统的多 普勒谱重叠度近似为零的情况下，能够对主辅SAR图像进行有效的图像融合以提高方位向分辨率，满足高质量干涉合成孔径雷达处理的性能要求。
但是，以上专利提供的分布式遥感卫星没有考虑到编队卫星之间的时间同步问题，无法保证两颗卫星同时覆盖地面的同一区域，导致两幅复影像干涉性能下降，甚至无法形成干涉。同时，时间不同步也导致遥感卫星无法基于时间信息得到地面区域变化的时空特征。而且，分布式合成孔径雷达系统在对两幅复影像干涉处理时，得到的相位差是[-π，π]之间的未知整数周期缠绕后的相位主值，需要对相位进行展开，而两颗卫星之间的时间不同步会导致相位展开有误差，而相位信息包含地形的高度信息，从而使得遥感系统无法得到精确的三维场景图像。
此外，现有技术中，如公开号为CN107395309的中国专利文献公开了一种基于星间链路的高精度相对测距与时间同步方法，该方法包括：分别以两颗卫星A、B各自的星载频标为基准建立星间链路，将测速信息和始终误差纳入动态误差模型；A、B两颗卫星在接收时隙内，分别对接收到的对方信号进行捕获、跟踪、解调，恢复出信息帧，联合对方测量时隙发送历元时计算出本地伪距；最后，A星和B星分别将修正之后的伪距嵌入到本地基带数据中发送给对方，两星各自独立的利用本地测得的修正伪聚合接收信息帧中解调出来的对方修正伪距，通过计算得到星间相对距离值和时差，并对两星进行时钟调整，修正卫星星历与时钟参数。但是，该专利只考虑到时间同步，而没有考虑到卫星平台上接收装置的频率漂移导致的干涉相位误差问题，也没有考虑到天线角度不一致，导致波束没有覆盖到同一地区的问题。
综上，有必要对现有的技术进行改进，在卫星编队合成孔径雷达系统提供高精细、宽幅、三维成像的情况下，通过时间、频率以及空间同步来补偿相位展开误差以提高地形测高的精度，并且基于时间、频率以及空间同步来获取地面区域变化的时空特征。
发明内容
针对现有技术不足，本发明提供一种遥感系统，尤其是一种基于卫星编队的遥感系统，其特征在于，包括以SAR系统为有效载荷的主星、第一辅星和第二辅星，所述第一辅星和第二辅星围绕所述主星飞行且所述主星位于所述第一辅星和第二辅星的运动轨迹的长轴上以形成具有相同切航迹基线分量的第一空间基线A和第二空间基线B。
有利地，所述主星以成像传感装置、同步装置为有效载荷，所述同步装置基于同步的时间、频率以及空间形成时间序列的第一空间基线A和第二空间基线B，所述成像传感装置根据第一空间基线A和第二空间基线B获取地面区域变化的时空特征。
有利地，在所述第一辅星和第二辅星的运动轨迹外设置有与所述主星前后编队飞行的以成像传感装置、同步装置为有效载荷的第三辅星，并且所述第三辅星位于所述主星相邻的轨道上，从而所述第三辅星相对所述主星形成长沿航迹基线C以及短切航迹基线D，其中，所述成像传感装置基于所述第一空间基线A和第二空间基线B，并结合所述短切航迹基线D和长沿航迹基线C进行最优干涉基线处理以在高精细宽幅成像的同时获得地形高程信息和动目标速度信息。
有利地，所述成像传感装置还设置有能够实时测量所述主星、第一辅星、第二辅星以及第三辅星的卫星姿态参数并能够实现精密定轨来获取高精度的所述第一空间基线A、第二空间基线B、长沿航迹基线C以及短切航迹基线D的测量装置。
有利地，所述成像传感装置还能够通过所述测量装置获得地面目标区域的先验信息，并基于地面目标区域的纬度信息而调整所述主星、第三辅星、第一辅星和第二辅星上的成像传感装置的天线角度以保持相同的高程模糊度，从而提高不同纬度地区的地面高程测量精度的一致性。
有利地，当基于先验信息获得的地面目标区域的地形高度变化幅度较大时，调整所述主星、第三辅星、第一辅星和第二辅星上的成像传感装置的天线角度以保持相同的且区别于第一高程模糊度的第二高程模糊度，使得所述SAR系统以至少两次不同的高程模糊度成像。
有利地，在所述第三辅星通过所述同步装置同步的情况下，所述第一空间基线A、第二空间基线B、短切航迹基线D和长沿航迹基线C形成时间序列的沿航迹基线和切航迹基线，其中，
所述成像传感装置基于时间序列的沿航迹切线获取动目标的速度随时间的变化信息，并基于时间序列的切航迹基线获取地面高程随时间的变化信息。
有利地，在所述主星的轨道参数确定的情况下，所述第一辅星和所述第二辅星的轨道参数基于第一空间基线A和第二空间基线B的切航迹有效基线的长度与切航迹有效基线的极限长度进行比较以调整所述第一辅星和所述第二辅星的飞行轨迹的短半轴的方式获得，所述第三辅星的轨道参数基于方位多普勒解模糊所需要的空间采样的要求以及多普勒解模糊精度的要求获得。
有利地，所述同步装置至少包括时间同步模块、频率同步模块以及空间同步模块，其中，所述时间同步模块被配置为：基于开机同时触发产生各星载有的定时脉冲信号并通过星间频率同步脉冲以获得星间的频率差值来实现时间同步。
有利地，所述同步装置中的频率同步模块被配置为：采用线性调频信号作为同步脉冲以周期性的方式交换所述主星与所述第一辅星或第二辅星或第三辅星上的同步脉冲信号处理以获得星上频率源引起的相位差异，从而进行相位补偿以实现频率同步。
有利地，所述同步装置中的空间同步模块被配置为：基于所述主星上的成像传感装置对地面目标区域的指向以及所述第一辅星或第二辅星或第三辅星的卫星姿态以使得所述第一辅星或第二辅星或第三辅星上的成像传感装置指向同一地面目标区域从而完成空间同步。
本发明还提供了一种星载SAR星座系统，其特征在于，包括：以SAR系统为有效载荷的主星、以及至少一对围绕所述主星飞行的第一辅星和第二辅星，其中，所述第一辅星和第二辅星围绕所述主星飞行且所述主星位于所述第一辅星和第二辅星的运动轨迹的长轴上以形成具有相同切航迹基线分量的第一空间基线A和第二空间基线B，其中，
所述第一辅星和第二辅星关于所述主星成中心对称的方式形成被动的稳定构型以使得所述第一辅星相对所述主星形成第一空间基线A，所述第二辅星关于所述主星形成第二空间基线B，其中，所述第一空间基线A与所述第二空间基线B长度相同且相位相反。
有利地，所述星载SAR星座系统还包括第三辅星，
所述第三辅星在所述第一辅星和第二辅星的飞行轨道外且与所述主星相邻的轨道上与所述第一主星前后编队飞行，从而相对所述主星形成长沿航迹基线C以及短切航迹基线D；所述SAR系统基于所述第一空间基线A和第二空间基线B生成长度大于所述短切航迹基线D长垂直基线和长度小于所述长沿航迹基线C的短水平基线，并结合所述短切航迹基线D和长沿航迹基线C进行最优干涉信号处理以在高分辨宽测绘带成像的同时提高地形高度测量的精度和量程。
有利地，在获得所述主星、第三辅星、第一辅星和第二辅星的轨道参数后，所述主星通过测量装置获取SAR雷达天线姿态参数以对所述主星、第三辅星、第一辅星和第二辅星实现精密定轨来获取高精度的所述第一空间基线A、第二空间基线B、水平基线C以及短切航迹基线D，
其中，所述测量装置至少包括用于姿态测量的GPS接收机，所述GPS接收机执行以下步骤：
对原始数据进行预处理，主要包括星历数据解码和数据同步；
通过差分定位算法，获取所述SAR雷达天线的位置参数；
利用所述SAR雷达天线的位置参数获得整周模糊度的初始值，利用卡尔曼滤波和递 归搜索的方法求解出整周模糊度的准确值，并利用载波相位获得精确的坐标；
利用获得精确坐标值，获得星间基线向量，并通过所述星间基线向量求解得到所述SAR雷达天线的姿态参数。
本发明还提供了一种卫星遥感系统，其特征在于，以SAR系统为有效载荷的主星、第三辅星以及至少一对围绕所述主星飞行的第一辅星和第二辅星，其中，在所述主星获得所述SAR雷达天线的姿态参数后，所述GPS接收机基于所述主星、第三辅星、第一辅星和第二辅星的轨道参数并与GPS星座相连接，至少获取日月摄动、太阳光压摄动以及大气阻力摄动的先验信息建立星座系统的轨道扰动模型以消除摄动对基线测量的影响；所述GPS接收机基于所述SAR雷达天线的姿态参数以及所述星座系统的轨道扰动模型得到的定轨结果以获得第一空间基线A、第二空间基线B长沿航迹基线C以及短切航迹基线D。
针对现有技术之不足，本发明提供了一种基于卫星编队的遥感系统，采用主星位于第一辅星和第二辅星运动轨迹的长轴且第三辅星与主星前后分飞行的编队构型形成具有相同长度且相位反向的切航迹基线分量的第一空间基线A和第二空间基线B，能够免第一空间基线A和第二空间基线B由于沿航迹基线和切航迹基线耦合导致得到的地面高度信息相位混杂有径向速度信息，从而能够提高地形测量高度的精度。而且，本发明通过同步装置基于时间、频率和空间同步获得具有时间序列的沿航迹基线和切航迹基线得到时间、频率等同步信息从而对接收的信号进行校正，并利用长、短切航迹基线进行相位展开，提高相位展开精度以进一步提高地形高度测量的精度，从而能够获得地面区域内高程以及速度随时间的微小变化。
有利地，一种基于卫星编队的遥感系统包括以成像传感装置、同步装置为有效载荷的主星、第一辅星和第二辅星。所述第一辅星和第二辅星围绕所述主星飞行且所述主星位于所述第一辅星和第二辅星的运动轨迹的长轴上以形成具有相同切航迹基线分量的第一空间基线A和第二空间基线B。所述成像传感装置根据所述同步装置基于时间、频率以及空间同步以形成时间序列的第一空间基线A和第二空间基线B从而获取地面区域变化的时空特征。
有利地，在所述第一辅星和第二辅星的运动轨迹外设置有与所述主星前后编队飞行的以成像传感装置、同步装置为有效载荷的第三辅星。所述第三辅星位于所述主星相邻的轨道上，从而所述第三辅星相对所述主星形成长沿航迹基线C以及短切航迹基线D。所述成像传感装置基于所述第一空间基线A和第二空间基线B，并结合所述短切航迹基 线D和长沿航迹基线C进行最优干涉基线处理以在高精细宽幅成像的同时获得地形高程信息和动目标速度信息。
有利地，在所述第三辅星通过所述同步装置同步的情况下，所述第一空间基线A、第二空间基线B、短切航迹基线D和长沿航迹基线C形成时间序列的沿航迹基线和切航迹基线。所述成像传感装置基于时间序列的沿航迹切线获取动目标的速度随时间的变化信息。所述成像传感装置基于时间序列的切航迹基线获取地面高程随时间的变化信息。
有利地，在所述主星的轨道参数确定的情况下，所述第一辅星和所述第二辅星的轨道参数基于第一空间基线A和第二空间基线B的切航迹有效基线的长度与切航迹有效基线的极限长度进行比较以调整所述第一辅星和所述第二辅星的飞行轨迹的短半轴的方式获得。所述第三辅星的轨道参数基于方位多普勒解模糊所需要的空间采样的要求以及多普勒解模糊精度的要求获得。
有利地，所述同步装置至少包括时间同步模块、频率同步模块以及空间同步模块。所述时间同步模块被配置为：基于开机同时触发产生各星载有的定时脉冲信号并通过星间频率同步脉冲以获得星间的频率差值来实现时间同步。
有利地，所述频率同步模块被配置为：采用线性调频信号作为同步脉冲以周期性的方式交换所述主星与所述第一辅星或第二辅星或第三辅星上的同步脉冲信号处理以获得星上频率源引起的相位差异，从而进行相位补偿以实现频率同步。
有利地，所述空间同步模块被配置为：基于所述主星上的成像传感装置对地面目标区域的指向以及所述第一辅星或第二辅星或第三辅星的卫星姿态以使得所述第一辅星或第二辅星或第三辅星上的成像传感装置指向同一地面目标区域从而完成空间同步。
有利地，所述成像传感装置还设置有能够实时测量所述主星、第一辅星、第二辅星以及第三辅星的卫星姿态参数并能够实现精密定轨来获取高精度的所述第一空间基线A、第二空间基线B、长沿航迹基线C以及短切航迹基线D的测量装置。
有利地，所述成像传感装置还能够通过所述测量装置获得地面目标区域的先验信息。所述成像传感装置基于地面目标区域的纬度信息而调整所述主星、第三辅星、第一辅星和第二辅星上的成像传感装置的天线角度以保持相同的高程模糊度，从而提高不同纬度地区的地面高程测量精度的一致性。
有利地，当基于先验信息获得的地面目标区域的地形高度变化幅度较大时，调整所述主星、第三辅星、第一辅星和第二辅星上的成像传感装置的天线角度以保持相同的且区别于第一高程模糊度的第二高程模糊度，使得所述SAR系统以至少两次不同的高程模 糊度成像。
针对现有技术之不足，本发明提供了一种星载SAR星座系统，采用第一辅星和第二辅星以主星为中心对称绕飞的方式形成被动稳定的轨道构型，第一辅星和第二辅星分别相对主星能够在轨道周期的任意时间内形成长度相同、相位反向的第一空间基线A和第二空间基线B，然后基于第一空间基线A和第二空间基线B解耦合得到包含地形高度信息的长垂直基线和包含速度信息的短水平基线，并结合第三辅星与主星之间形成的长沿航迹基线C和短切航迹基线D，使得SAR系统能够基于长垂直基线、短切航迹基线D、长沿航迹基线C和短水平基线进行最优干涉信号处理以在高分辨宽测绘带成像的同时提高地形高度测量的精度和量程。
有利地，一种星载SAR星座系统，包括：以SAR系统为有效载荷的主星、第三辅星以及至少一对围绕所述主星飞行的第一辅星和第二辅星。所述第一辅星和第二辅星关于所述主星成中心对称的方式形成被动的稳定构型以使得所述第一辅星相对所述主星形成第一空间基线A。所述第二辅星关于所述主星形成第二空间基线B。所述第一空间基线A与所述第二空间基线B长度相同且相位相反。所述第三辅星在所述第一辅星和第二辅星的飞行轨道外且与所述主星相邻的轨道上与所述第一主星前后编队飞行，从而相对所述主星形成长沿航迹基线C以及短切航迹基线D。所述SAR系统基于所述第一空间基线A和第二空间基线B生成长度大于所述短切航迹基线D的垂直基线和长度小于所述长沿航迹基线C的水平基线，并结合所述短切航迹基线D和长沿航迹基线C进行最优干涉信号处理以在高分辨宽测绘带成像的同时提高地形高度测量的精度和量程。
有利地，所述第三辅星的轨道参数采用以下步骤获得：根据任务需求，获得所述主星的轨道参数，其中，主星轨道的偏心率为0；第一辅星和第二辅星的长半轴、轨道倾角和升交点赤经均与所述主星相同，并且第一辅星和第二辅星飞行轨迹的短半轴、半长轴由Hill方程计算获得，其中，所述第一辅星和第二辅星的飞行轨迹的短半轴的设计初值为任务的基线要求；根据所述第一辅星和第二辅星的飞行轨迹的相位差，确定近地点幅角和平近点角；根据当前计算得到的所有卫星的轨道参数，计算一个轨道周期内的所述第一空间基线A和第二空间基线B有效垂直基线长度，判断其是否小于垂直有效基线的极限基线长度；若不小于垂直有效基线的极限基线长度，则对所述第一辅星和第二辅星的飞行轨迹的短半轴进行调整，直至所述第一空间基线A和第二空间基线B的有效垂直基线长度满足要求；根据以上步骤得到的所述主星、第一辅星和第二辅星的轨道参数来计算在所述长沿航迹基线C满足方位多普勒解模糊所需要的空间采样的要求以及所述短 切航迹基线D满足多普勒解模糊精度的要求的情况下所述第三辅星的轨道参数。
有利地，在获得所述主星、第三辅星、第一辅星和第二辅星的轨道参数后，所述主星通过测量装置获取SAR雷达天线姿态参数以对所述主星、第三辅星、第一辅星和第二辅星实现精密定轨来获取高精度的所述第一空间基线A、第二空间基线B、水平基线C以及短切航迹基线D。所述测量装置至少包括用于姿态测量的GPS接收机。所述GPS接收机执行以下步骤：对原始数据进行预处理，主要包括星历数据解码和数据同步；通过差分定位算法，获取所述SAR雷达天线的位置参数；利用所述SAR雷达天线的位置参数获得整周模糊度的初始值，利用卡尔曼滤波和递归搜索的方法求解出整周模糊度的准确值，并利用载波相位获得精确的坐标；利用获得精确坐标值，获得星间基线向量，并通过所述星间基线向量求解得到所述SAR雷达天线的姿态参数。
有利地，在所述主星获得所述SAR雷达天线的姿态参数后，所述GPS接收机基于所述主星、第三辅星、第一辅星和第二辅星的轨道参数并与GPS星座相连接，至少获取日月摄动、太阳光压摄动以及大气阻力摄动的先验信息建立所述星座系统的轨道扰动模型以消除摄动对基线测量的影响；所述GPS接收机基于所述SAR雷达天线的姿态参数以及所述星座系统的轨道扰动模型得到的定轨结果以获得所述第一空间基线A、第二空间基线B长沿航迹基线C以及短切航迹基线D。
有利地，在所述主星通过所述GPS星座获取先验信息之前，所述主星进行时间同步以避免时钟误差带来影响。所述主星、第三辅星、第一辅星和第二辅星均包括同步装置。所述同步装置至少包括时间同步组件。所述时间同步组件被配置为：基于开机同时触发产生各星载有的定时脉冲信号并通过星间频率同步脉冲以获得星间的频率差值来实现时间同步。
有利地，所述同步装置还包括频率同步组件。所述频率同步组件被配置为：采用频率线性时变信号作为同步脉冲以周期性的方式中断任意两星载SAR信息的获取，并通过对交换的同步脉冲信号处理以获得任意两星上频率源引起的相位差异。基于所述相位差异对所述SAR进行相位补偿以实现频率同步。
有利地，在所述主星通过所述同步装置与所述第三辅星同步和/或所述第一辅星以及第二辅星同步的情况下，所述第一空间基线A、第二空间基线B、水平基线C以及短切航迹基线D形成时间序列的水平基线和垂直基线。
有利地，在所述主星通过所述同步装置与所述GPS星座连接获得先验信息后，所述主星根据所述GPS星座的先验信息获取地面观测区域的纬度信息而调整所述第三辅星、 第一辅星和第二辅星的天线角度以保持相同的高程模糊度从而提高不同纬度地区的高程测量精度的一致性。
有利地，一种星载SAR成像方法，该方法包括：使用以SAR系统为有效载荷的主星、第三辅星以及至少一对围绕所述主星飞行的第一辅星和第二辅星构成的星座进行成像。所述第一辅星和第二辅星关于所述主星成中心对称的方式形成被动的稳定构型以使得所述第一辅星和所述第二辅星分别相对所述主星形成长度相同、相位相反的第一空间基线A和第二空间基线B。所述第三辅星在所述第一辅星和第二辅星的飞行轨道外且与所述第一主星相邻的轨道上与所述第一主星前后编队飞行。所述第三辅星相对所述第一主星形成长沿航迹基线C以及短切航迹基线D。所述SAR系统基于所述第一空间基线A和第二空间基线B生成较长的垂直基线和较短的水平基线，并结合所述短切航迹基线D和长沿航迹基线C进行最优干涉信号处理以在高分辨宽测绘带成像的同时提高地形测量的精度和量程。
有利地，在所述主星通过同步装置与GPS星座连接获得先验信息后，所述主星基于所述GPS星座的先验信息获取地面观测区域的纬度信息而调整所述主星、第三辅星、第一辅星和第二辅星上SAR系统的天线角度以保持相同的高程模糊度，从而提高不同纬度地区的高程测量精度的一致性。在所述主星、第三辅星、第一辅星和第二辅星上SAR系统的天线角度保持相同的第一高程模糊度成像后，当基于先验信息获得的地面观测区域的地形高度变化幅度较大时，调整所述主星、第三辅星、第一辅星和第二辅星上SAR系统的天线角度以保持相同的且区别于第一高程模糊度的第二高程模糊度，使得所述SAR系统以至少两次不同的高程模糊度成像。
本发明的有益技术效果包括以下一下或多项：
1、能避免第一空间基线A和第二空间基线B由于沿航迹基线和切航迹基线耦合导致得到的地面高度信息相位混杂有径向速度信息，从而能够提高地形测量高度的精度；
2、时间和空间同步能够保证两颗卫星的主波束在同时覆盖地面同一区域，并且能够保证两星接收回波信号的时间窗口同步；频率同步能够减少两星各自频率漂移导致的干涉相位误差；
3、长沿航迹基线C、第一空间基线A以及第二空间基线B包含径向速度信息，能够为动目标检测提供条件，并且长沿航迹基线C和短沿航迹基线还能够提供方位向多普勒解模糊提供所需要的空间采样，进而弥补低方位重频造成的时间采样的不足，从而为方位向解多普勒模糊提供条件以实现高精细、宽幅成像；
4、由于短切航迹基线D的测高精度不高，基于第一空间基线A以及第二空间基线B中的长切航迹基线分量进行相位展开时可能会错误解缠，而采用本发明后，利用时间序列的沿航迹基线和切航迹基线得到时间、频率等同步信息从而对接收的信号进行校正，并利用长、短切航迹基线进行相位展开，提高相位展开精度以进一步提高地形高度测量的精度，从而能够获得地面区域内高程、速度随时间的微小变化。
附图说明
图1是本发明的一个优选成像传感装置和同步装置的模块示意图；和
图2是本发明的一个优选卫星编队的几何示意图。
附图标记列表
100：主星                                 101：第三辅星
200：第一辅星                             201：第二辅星
300：成像传感装置                         400：同步装置
310：测量装置                             410：时间同步模块
420：频率同步模块                         430：空间同步模块
A：第一空间基线                           B：第二空间基线
C：长沿航迹基线                           D：短切航迹基线
具体实施方式
下面结合附图1和附图2进行详细说明。本发明中的各个“模块”，分别可以是专用集成芯片、服务器、服务器组中的一种或几种。本发明的模块描述任一种硬件、软件或软硬件组合，其能够执行与“模块”相关联的功能。
根据一个可行方式，本发明公开了一种遥感成像方法，也可以是一种基于卫星的遥感成像方法，也可以是一种基于分布式合成孔径雷达遥感成像方法，也可以是一种基于卫星编队的遥感成像方法，该方法可以由本发明的系统和/或其他可替代的零部件实现。比如，通过使用本发明的系统中的各个零部件实现本方法的系统。在不造成冲突或者矛盾的情况下，其他实施例的优选实施方式的整体和/或部分内容可以作为本实施例的补充。
有利地，本成像方法包括以成像传感装置300、同步装置400为有效载荷的主星100、第一辅星200和第二辅星201。第一辅星200和第二辅星201围绕主星100飞行且主星100位于第一辅星200和第二辅星201的运动轨迹的长轴上以形成具有相同切航迹基线分量的第一空间基线A和第二空间基线B。成像传感装置300根据同步装置400基 于时间、频率以及空间同步以形成时间序列的第一空间基线A和第二空间基线B从而获取地面区域变化的时空特征。优选地，成像传感装置300至少包括能够主动或被动获取地面信息的成像传感器。成像传感器可以是雷达、激光等能够成像的。成像传感器可以是能够以合成孔径的方式成像的传感器，例如，合成孔径雷达、合成孔径激光雷达等。优选地，第一辅星200和第二辅星201以主星100为轨道运行中心，并利用Hill方程将它们设计为不需要消耗燃料的被动稳定的构型。如图2所示，第一辅星200和第二辅星201的运动轨迹在Hill方程的描述下为椭圆形的轨迹。由于主星100、第一辅星200和第二辅星201运行在同一轨道平面内，第一辅星200和第二辅星201具有相同的轨道周期，相同的半长轴和偏心率，各卫星星体之间不存在水平方向上的位置偏移，使得第一辅星200和第二辅星201在空间形成椭圆形的空间构型。通过该方式，本发明可以使得第一辅星200和第二辅星201和主星100能够保持相对的空间位置，从而能够得到稳定的第一空间基线A和第二空间基线B。而且，第一空间基线A和第二空间基线B是随着椭圆构型的旋转周期而呈周期性变化，从而第一空间基线A和第二空间基线B是包含有速度信息和地形高度信息的混合基线。
优选地，主星100、第一辅星200和第二辅星201上的成像装置300接收主星100发送至地面目标返回的回波信号。成像装置300内的合成孔径雷达成像传感器采用低方位重复采样的方式获得地面目标的多幅合成孔径雷达图像，通过拼接多幅合成孔径雷达图像以形成高精细、宽幅的合成孔径雷达图像。第一空间基线A和第二空间基线B包含有速度信息和地形高度信息的相位，为高精细、宽幅、三维成像提供条件。
优选地，第一空间基线A和第二空间基线B由于主星100位于长轴上，从而具有长度相同，相位反向的切航迹基线分量，因此可以采用例如差分处理的方式得到只包含地形高度信息的切航迹基线和只包含速度信息的沿航迹基线。本发明采用此方式至少能够实现的有益技术效果是：能避免第一空间基线A和第二空间基线B由于沿航迹基线和切航迹基线耦合导致得到的地面高度信息相位混杂有径向速度信息，从而能够提高地形测量高度的精度。
优选地，第一空间基线A和第二空间基线B基于同步装置400可以在时间、频率以及空间上同步得到时间序列的第一空间基线A和第二空间基线B，从而得到时间序列的沿航迹基线和切航迹基线。优选地，时空特征指的是时间序列的切航迹基线包含地面高程随时间变化的信息，时间序列的沿航迹基包含目标的速度随是时间变化的信息。例如，通过本发明可以得到农作物、森林等高度随时间的微小变化。同时，也可以得到平原、 山体等高度随时间的微小变化。例如，通过以上信息可以提前获取农作物的生长发育状况及其变化态势，能够与去年、多年平均以及指定某一年的同期数据进行对比，可以实时地获得农作物生长差异，即空间分布、高度分布的变化状态，从而能够分区域统计水田、旱地、耕地和主要作物中不同长势等级所占比重。例如，通过平原、山体的高精度的高度数据与过去不同时期对比，获取其微小的变化趋势，能够监测山体滑坡、垮塌等灾害。本发明通过此方式还可以利用时间序列的沿航迹基线的径向速度实现目标的提取与速度估计。例如，可以在海水里利用海水与海冰的回波信号的相干系数的差异实现海冰与海水的分离，并通过时间序列的沿航迹基线获取海冰和海水的径向速度信息，从而获得相应的速度估计。
有利地，同步装置400至少包括时间同步模块410、频率同步模块420以及空间同步模块430。时间同步模块410被配置为：基于开机同时触发产生各星载有的定时脉冲信号并通过星间频率同步脉冲以获得星间的频率差值来实现时间同步。优选地，可以通过GPS秒脉冲来实现开机触发定时脉冲信号。优选地，如图1所示，主星100发射的信号经过地面反射后形成回波信号。回波信号在经过同步装置400后通过成像传感装置300进行处理。
有利地，频率同步模块420被配置为：采用线性调频信号作为同步脉冲以周期性的方式交换主星100与第一辅星200或第二辅星201或第三辅星101上的同步脉冲信号处理以获得星上频率源引起的相位差异，从而进行相位补偿以实现频率同步。优选地，频率线性时变信号为啁啾信号。优选地，主星100、第三辅星101、第一辅星200以及第二辅星201都安装6个同步喇叭天线以提供准全向波束覆盖，保证近实时全方位的频率同步脉冲接收。优选地，主星100分别向第三辅星101、第一辅星200以及第二辅星201发送同步脉冲。由于啁啾信号其频率随时间线性变化的特性会导致主星100的合成孔径雷达数据获取将会被周期性地中断。在一个周期内，同步脉冲将从主星100的成像传感装置300的主天线上发射至第三辅星101和/或第一辅星200和/或第二辅星201上专用于同步的喇叭天线，第三辅星101和/或第一辅星200和/或第二辅星201记录该脉冲后再回传一短同步脉冲给主星100，通过对交换的同步脉冲信号处理获得主星100相对其他辅星上频率源引起的相位差异，在各星上的成像传感装置300成像时再进行相应的相位补偿，从而完成频率同步。优选地，采用频率线性时变信号作为脉冲信号后，也可以认为卫星上频率源的频率为常数，可以从同步信号相位差的线性部分提取出频率差，进而完成时间同步。
有利地，空间同步模块430被配置为：基于主星100上的成像传感装置300对地面目标区域的指向以及第一辅星200或第二辅星201或第三辅星101的卫星姿态以使得第一辅星200或第二辅星201或第三辅星101上的成像传感装置300指向同一地面目标区域从而完成空间同步。通过此方式，主星100上的成像传感装置300的天线采用正侧视的方式 指向成像区域，第一辅星200、第二辅星201以及第三辅星101能够采用小角度斜视指向成像区域的方式观测地面目标成像。本发明采用以上方式至少能够实现以下有益技术效果：第一，时间和空间同步能够保证两颗卫星的主波束在同时覆盖地面同一区域，并且能够保证两星接收回波信号的时间窗口同步；第二，频率同步能够减少两星各自频率漂移导致的干涉相位误差。
根据一个可行方式，在第一辅星200和第二辅星201的运动轨迹外设置有与主星100前后编队飞行的以成像传感装置300、同步装置400为有效载荷的第三辅星101。第三辅星101位于主星100相邻的轨道上，从而第三辅星101相对主星100形成长沿航迹基线C以及短切航迹基线D。成像传感装置300基于第一空间基线A和第二空间基线B，并结合短切航迹基线D和长沿航迹基线C进行最优干涉基线处理以在高精细宽幅成像的同时获得地形高程信息和动目标速度信息。优选地，成像传感装置300基于第一空间基线A和第二空间基线B生成长度大于短切航迹基线D的长切航迹基线和长度小于长沿航迹基线C的短沿航迹基线，并结合短切航迹基线D和长沿航迹基线C进行最优干涉信号处理以在高分辨宽测绘带成像的同时提高地形高度测量的精度和量程。优选地，第三辅星101的轨道与主星100的轨道相距至少为120m，避免并且第三辅星101的轨道与主星100的轨道的距离是保持固定的，如图2所示。基于确定的轨道距离可以将第三辅星101相对主星100形成的空间基线分解得到短切航迹基线D和长沿航迹基线C。通过该方式，本发明的短切航迹基线D在第三辅星101以及主星100在轨运行的阶段内是始终确定且保持不变的，能够为第三辅星101和主星100的精确定轨和基线测量提供先验条件和误差分析。
优选地，主星100、第三辅星101、第一辅星200和第二辅星201上的成像传感装置300接收主星100发送至地面目标返回的回波信号。成像传感装置300采用低方位重复采样的方式获得地面目标的多幅合成孔径雷达图像。由于成像传感装置300采用低方位重复采样的方式获取图像，会导致方位向多普勒模糊。优选地，方位多普勒频率与方位瞬时斜视角的正弦成正比且一一对应的关系。当方位重复率较低小于多普勒带宽时，方位多普勒谱出现混叠而存在模糊，并且其方位多普勒频率不再与方位瞬时斜视角的正弦成正比，而是由多个指向方位瞬时斜视角的能量混合而成。方位向多普勒解模糊的过程是针对每一个多普勒频率，在多个指向方位瞬时斜视角的能量混叠的情况下，逐个提取特定指向方位瞬时斜视角的能量，最后通过拼接重建不模糊的多普勒谱。本发明采用此方式至少能够实现的至少以下有益技术效果：第一，长沿航迹基线C和短沿航迹基线包含径向速度信息，能够为动目标检测提供条件；第二，长沿航迹基线C和短沿航迹基 线还能够提供方位向多普勒解模糊提供所需要的空间采样，进而弥补低方位重频造成的时间采样的不足，从而为方位向解多普勒模糊提供条件。
优选地，第一空间基线A、第二空间基线B以及第三辅星101相对主星100形成的物理基线的存在会引入空变矢量。将第一空间基线A、第二空间基线B以及第三辅星101相对主星100形成的空间基线分解得到长切航迹基线和短切航迹基线D，长切航迹基线和短切航迹基线D的多基线干涉处理能够得到每个多普勒频率中的切航迹基线引入的相位信息。本发明采用此方式至少能够实现的至少以下有益技术效果：第一，基于得到的相位信息在解多普勒模糊前进行相位补偿以在满足多普勒解模糊精度的情况下提高地形测量高度的量程；第二，长切航迹基线和短切航迹基线D的多基线干涉处理还能够提高地形高度测量的精度。
有利地，在主星100的轨道参数确定的情况下，第一辅星20和第二辅星201的轨道参数基于第一空间基线A和第二空间基线B的切航迹有效基线的长度与切航迹有效基线的极限长度进行比较以调整第一辅星20和第二辅星201的飞行轨迹的短半轴的方式获得。第三辅星101的轨道参数基于方位多普勒解模糊所需要的空间采样的要求以及多普勒解模糊精度的要求获得。优选地，第三辅星101的轨道参数采用以下步骤获得：根据任务需求，获得主星100的轨道参数，其中，主星轨道的偏心率为0；第一辅星200和第二辅星201的长半轴、轨道倾角和升交点赤经均与主星100相同，并且第一辅星200和第二辅星201飞行轨迹的短半轴、半长轴由Hill方程计算获得，其中，第一辅星200和第二辅星201的飞行轨迹的短半轴的设计初值为任务的基线要求；根据第一辅星200和第二辅星201的飞行轨迹的相位差，确定近地点幅角和平近点角；根据当前计算得到的所有卫星的轨道参数，计算一个轨道周期内的第一空间基线A和第二空间基线B有效切航迹基线长度，判断其是否小于切航迹有效基线的极限基线长度；若不小于切航迹有效基线的极限基线长度，则对第一辅星200和第二辅星201的飞行轨迹的短半轴进行调整，直至第一空间基线A和第二空间基线B的有效切航迹基线长度满足要求；根据以上步骤得到的主星100、第一辅星200和第二辅星201的轨道参数来计算在长沿航迹基线C满足方位多普勒解模糊所需要的空间采样的要求以及短切航迹基线D满足多普勒解模糊精度的要求的情况下第三辅星101的轨道参数。优选地，假设主星100的轨道为圆形，即偏心率为0，根据轨道类型、轨道高度等参数结合Hill方程组获得主星轨道的6根数，即轨道半长轴、轨道偏心率、轨道离心率、轨道倾角、升交点赤经、近地点幅角以及指定历元的平近点角。优选地，描述辅星运动的Hill方程为：
Figure PCTCN2019121956-appb-000001
其中，式中坐标系原点定义为主星100，主星沿绕地球轨道卫星，x轴指向参考卫星的飞行方向，y轴垂直于主星100的轨道平面，z轴背向地心指向主星100。
Figure PCTCN2019121956-appb-000002
ψ k标识第k个辅星在椭圆轨道构型中的初始位置，T表示轨道周期。优选地，主星100为第一辅星200和第二辅星201的中心，因此B为0。优选地，第一辅星200和第二辅星201相对运动在XZ平面为椭圆轨迹，并且沿速度方向X方向的长半轴是垂直于速度方向Z方向短半轴的2倍。优选地，第一辅星200和第二辅星201相对运动在y轴做独立的正弦运动。第一辅星200和第二辅星201以主星100为中心的椭圆构型缓慢转动。在第一辅星200、第二辅星201和主星100均在同一轨道平面内，因此三者的轨道倾角和升交点赤经均相同。优选地，以基线为编队飞行形成的椭圆轨迹的短半轴设计初值。由于编队飞行相对运动的椭圆轨迹的短半轴仅与卫星的半长轴和偏心率有关，在半长轴已经确定的情况下，通过短半轴确定第一辅星200和第二辅星201的偏心率。优选地，由于主星100位于，第一辅星200和第二辅星201运动轨迹的长轴上，因此可以确定第一辅星200和第二辅星201的近地点幅角和平近点角。优选地，根据以上获得的主星100、第一辅星200和第二辅星201的轨道参数，可以计算一个轨道周期内的第一辅星200和第二辅星201分别相对主星100的第一空间基线A、第二空间基线B的长度。基于得到的第一空间基线A、第二空间基线B对地球表面进行投影得到有效基线，并使得切航迹有效基线的长度满足多普勒解模糊精度要求，沿航迹有效基线的长度满足方位多普勒解模糊所需要的空间采样的要求，从而切航迹有效基线的长度以及沿航迹有效基线的长度均应小于相应的极限基线长度。切航迹有效基线的极限基线长度：
Figure PCTCN2019121956-appb-000003
沿航迹有效基线的极限基线长度：
Figure PCTCN2019121956-appb-000004
其中，λ为成像传感装置300的工作波长，θ为视角，
Figure PCTCN2019121956-appb-000005
为斜视角，α为各卫星质心的连线与水平面的夹角，即基线倾角，β为地形坡度，R表示形成基线的两个卫星距离地面目标的平均斜距。p r和p a分别表示距离向和方位向分辨率。R可以根据式4得到，其中a主星100的轨道半长轴，R e为地球半径：
Figure PCTCN2019121956-appb-000006
p r和p a可以根据式5得到，其中，c为光速，B w表示信号带宽，D表示方位向天线尺寸：
Figure PCTCN2019121956-appb-000007
优选地，基于以上条件完成主星100、第一辅星200和第二辅星201的轨道设计参数来计算第三辅星101的轨道参数。第三辅星101的轨道与主星100的轨道保持固定的距离。优选地，第三辅星101与主星100按照前后编队飞行方式设置。优选地，第三辅星101与主星100的前后距离满足沿航迹有效基线的极限基线长度。
本发明采用此方式至少能够实现以下有益技术效果：第一，第一辅星200、第二辅星201以及主星100是共轨道面飞行，椭圆形的空间构型被动稳定，动力系统仅在轨道修正或任务切换时开启，节省能源；第二，第三辅星101的轨道与主星100的轨道相近且采用前后编队飞行的方式，能够保证编队卫星在任何时刻都能够得到满足方位多普勒解模糊所需要的空间采样的要求的沿航迹基线，提高系统成像效率；第三，第三辅星101、第一辅星200、第二辅星201以及主星100所形成的空间构型为共轨道面构型，该构型容易维持，燃料消耗较低；第四，本发明的编队构型能够形成稳定的基线和基线倾角，适用于干涉合成孔径雷达成像；第五，本发明的编队构型能够任意时刻形成多条有效切航迹基线和多条有效沿航迹基线，并且多条有效切航迹基线和多条有效沿航迹基线均满足多基线干涉处理的要求；第六，本发明的编队构型任意时间形成的有效切航迹基线满足多普勒解模糊精度要求，有效沿航迹基线满足方位多普勒解模糊所需要的空间采样的要求，从而满足合成孔径雷达系统能够任意时间高精细、宽幅成像的同时提高地面高度测量的精度和量程。
有利地，在第三辅星101通过同步装置400同步的情况下，第一空间基线A、第二空间基线B、短切航迹基线D和长沿航迹基线C形成时间序列的沿航迹基线和切航迹基线。成像传感装置300基于时间序列的沿航迹切线获取动目标的速度随时间的变化信息。成像传感装置300基于时间序列的切航迹基线获取地面高程随时间的变化信息。
优选地，在利用长切航迹基线和短切航迹基线D进行合成孔径雷达干涉成像时，从干涉图中得到的相位差是[-π，π]之间的未知整数周期缠绕后的相位主值，需要将缠绕的相位恢复成真实相位差，即相位展开。优选地，成像传感装置300基于时间序列的沿航迹基线和切航迹基线得到时间、频率等同步信息从而对接收的信号进行校正。成像传感装置300基于校正的信息进行相位补偿，并利用短切航迹基线对长切航迹基线进行相位展开，从而进一步提高地形高度测量的精度。本发明采用此方式至少能够实现以下有益技术效果：由于短切航迹基线D的测高精度不高，对长切航迹基线进行相位展开时可能会错误解缠，而采用本发明后，利用时间序列的沿航迹基线和切航迹基线得到时间、 频率等同步信息从而对接收的信号进行校正，并利用长、短切航迹基线进行相位展开，提高相位展开精度以进一步提高地形高度测量的精度，从而能够获得地面区域内高程以及速度的微小变化。
根据一个可行方式成像传感装置300还设置有能够实时测量主星100、第一辅星200、第二辅星201以及第三辅星101的卫星姿态参数并能够实现精密定轨来获取高精度的第一空间基线A、第二空间基线B、长沿航迹基线C以及短切航迹基线D的测量装置310。优选地，测量装置310至少包括用于姿态测量的GPS接收机。GPS接收机执行以下步骤：对原始数据进行预处理，主要包括星历数据解码和数据同步；通过差分定位算法，获取成像传感装置300的天线的位置参数；利用成像传感装置300天线的位置参数获得整周模糊度的初始值，利用卡尔曼滤波和递归搜索的方法求解出整周模糊度的准确值，并利用载波相位获得精确的坐标；利用获得精确坐标值，获得星间基线向量，并通过星间基线向量求解得到成像传感装置300天线的姿态参数。
优选地，GPS接收机为高精度双频GPS接收机。优选地，高精度双频GPS接收机内集成GPS掩星接收机。优选地，GPS接收机将接受到的原始数据预处理后，进行单点定位坐标解算，然后通过码双差定位解算移动坐标站坐标，获取成像传感装置300天线的粗略位置坐标。优选地，GPS接收机为获取精确的成像传感装置300天线位置坐标，需要采用波长为厘米级，测距误差为毫米级的载波相位方法来测距。由于载波信号是一种周期性的正弦信号，因此当被测距离大于波长时会出现整周模糊度。优选地，GPS接收机基于粗略位置坐标获得整周模糊度的初始值，利用卡尔曼滤波和递归搜索的方法求解出整周模糊度的准确值。
优选地，在主星100获得成像传感装置300天线的姿态参数后，GPS接收机基于主星100、第三辅星101、第一辅星200和第二辅星201的轨道参数并与GPS星座相连接，至少获取日月摄动、太阳光压摄动以及大气阻力摄动的先验信息建立卫星编队的轨道扰动模型以消除摄动对基线测量的影响；GPS接收机基于成像传感装置300的天线的姿态参数以及编队的轨道扰动模型得到的定轨结果以差分载波相位测量法获得第一空间基线A、第二空间基线B长沿航迹基线C以及短切航迹基线D。
优选地，地球非球形摄动、太阳光压摄动以及大气阻力摄动等对卫星的影响不可忽略，可以作为模型噪声结合先验信息进行估计。优选地，轨道扰动模型为地球非球形摄动、太阳光压摄动以及大气阻力摄动带来的对卫星运动影响的加速度的线性累加。优选地，差分载波相位测量法为将两星的路径延迟和算法引起的定轨误差进行差分以消除两星的大部分公共误差分量，将两星定轨结果差分即得到相应的基线矢量。本发明采用此方式至少能够实现以下有益技术效果：GPS接收机能够消除两星大部分共有的定轨误差，再通过算法优化和建立轨道扰动模型进行相应的补偿，能够精确的测量星间基线和卫星的姿态参数。
有利地，成像传感装置300还能够通过测量装置310获得地面目标区域的先验信息。 成像传感装置300基于地面目标区域的纬度信息而调整主星100、第三辅星101、第一辅星200和第二辅星201上的成像传感装置300的天线角度以保持相同的高程模糊度，从而提高不同纬度地区的地面高程测量精度的一致性。优选地，高程模糊度反应了干涉相位的变化对高程变化的敏感程度。当切航迹基线较长时，高程模糊度较小，干涉相位对于高程变化的敏感程度越强。当切航迹基线过短时，干涉相位对于高程变化不敏感，减小了地形高度测量的精度。优选地，高程模糊度与方位瞬时斜视角的正弦成正比，并且由于地球自转的原因，导致空间基线投影到地面得到的有效基线在不同的纬度其长度不同，通过调整成像传感装置300的天线角度能够调整高程模糊度。本发明采用此方式至少能够实现以下有益技术效果：主星100能够根据GPS星座的先验信息获取地面观测区域的纬度信息而调整天线角度以保持相同的高程模糊度，从而提高不同纬度地区的高程测量精度的一致性。
有利地，当基于先验信息获得的地面目标区域的地形高度变化幅度较大时，调整主星100、第三辅星101、第一辅星200和第二辅星201上的成像传感装置300的天线角度以保持相同的且区别于第一高程模糊度的第二高程模糊度，使得SAR系统以至少两次不同的高程模糊度成像。优选地，在主星100、第三辅星101、第一辅星200和第二辅星201上成像传感装置300的天线角度保持相同的第一高程模糊度成像后，当基于先验信息获得的地面观测区域的地形高度变化幅度较大时，调整主星100、第三辅星101、第一辅星200和第二辅星201上成像传感装置300的天线角度以保持相同的且区别于第一高程模糊度的第二高程模糊度，使得成像传感装置300系以至少两次不同的高程模糊度成像。优选地，当成像区域的地形起伏较大时，会造成相位主值不连续从而导致相位展开误差偏大。优选地，成像传感装置300基于调整天线角度以不同的高程模糊度成像以检查两次成像相位展开的一致性以及同一成像区域的差异，从而减少相位展开误差。本发明采用此方式至少能够实现以下有益技术效果：在对陡峭地区等地形起伏较大的地区成像时，以不同的高程模糊度成像来减少相位展开的误差，提高相对精度，从而提高地形测量高度的精度。
如本文所用的词语“模块”描述任一种硬件、软件或软硬件组合，其能够执行与“模块”相关联的功能。
虽然已经详细描述了本发明，但是在本发明的精神和范围内的修改对于本领域技术人员将是显而易见的。这样的修改也被认为是本公开的一部分。鉴于前面的讨论、本领域的相关知识以及上面结合背景讨论的参考或信息(均通过引用并入本文)，进一步的描述被认为是不必要的。此外，应该理解，本发明的各个方面和各个实施例的各部分均可 以整体或部分地组合或互换。而且，本领域的普通技术人员将会理解，前面的描述仅仅是作为示例，并不意图限制本发明。

Claims (15)

  1. 一种遥感系统，尤其是一种基于卫星编队的遥感系统，其特征在于，
    包括以SAR系统为有效载荷的主星(100)、第一辅星(200)和第二辅星(201)，
    所述第一辅星(200)和第二辅星(201)围绕所述主星(100)飞行且所述主星(100)位于所述第一辅星(200)和第二辅星(201)的运动轨迹的长轴上以形成具有相同切航迹基线分量的第一空间基线(A)和第二空间基线(B)。
  2. 如权利要求1所述的系统，其特征在于，所述主星(100)以成像传感装置(300)、同步装置(400)为有效载荷，
    所述同步装置(400)基于同步的时间、频率以及空间形成时间序列的第一空间基线(A)和第二空间基线(B)，
    所述成像传感装置(300)根据第一空间基线(A)和第二空间基线(B)获取地面区域变化的时空特征。
  3. 如权利要求1或2所述的系统，其特征在于，在所述第一辅星(200)和第二辅星(201)的运动轨迹外设置有与所述主星(100)前后编队飞行的以成像传感装置(300)、同步装置(400)为有效载荷的第三辅星(101)，并且所述第三辅星(101)位于所述主星(100)相邻的轨道上，从而所述第三辅星(101)相对所述主星(100)形成长沿航迹基线(C)以及短切航迹基线(D)，其中，
    所述成像传感装置(300)基于所述第一空间基线(A)和第二空间基线(B)，并结合所述短切航迹基线(D)和长沿航迹基线(C)进行最优干涉基线处理以在高精细宽幅成像的同时获得地形高程信息和动目标速度信息。
  4. 如前述权利要求之一所述的系统，其特征在于，所述成像传感装置(300)还设置有能够实时测量所述主星(100)、第一辅星(200)、第二辅星(201)以及第三辅星(101)的卫星姿态参数并能够实现精密定轨来获取高精度的所述第一空间基线(A)、第二空间基线(B)、长沿航迹基线(C)以及短切航迹基线(D)的测量装置(310)。
  5. 如前述权利要求之一所述的系统，其特征在于，所述成像传感装置(300)还能够通过所述测量装置(310)获得地面目标区域的先验信息，并基于地面目标区域的纬度信息而调整所述主星(100)、第三辅星(101)、第一辅星(200)和第二辅星(201)上的成像传感装置(300)的天线角度以保持相同的高程模糊度，从而提高不同纬度地区的地面高程测量精度的一致性。
  6. 如前述权利要求之一所述的系统，其特征在于，当基于先验信息获得的地面目标区域的地形高度变化幅度较大时，调整所述主星(100)、第三辅星(101)、第一辅星(200)和第二辅星(201)上的成像传感装置(300)的天线角度以保持相同的且区别于第一高程模糊度的第二高程模糊度，使得所述SAR系统以至少两次不同的高程模糊度成像。
  7. 如前述权利要求之一所述的系统，其特征在于，在所述第三辅星(101)通过所述同步装置(400)同步的情况下，所述第一空间基线(A)、第二空间基线(B)、短切航迹基线(D)和长沿航迹基线(C)形成时间序列的沿航迹基线和切航迹基线，其中，
    所述成像传感装置(300)基于时间序列的沿航迹切线获取动目标的速度随时间的变化信息，并基于时间序列的切航迹基线获取地面高程随时间的变化信息。
  8. 如前述权利要求之一所述的系统，其特征在于，在所述主星(100)的轨道参数确定的情况下，
    所述第一辅星(200)和所述第二辅星(201)的轨道参数基于第一空间基线(A)和第二空间基线(B)的切航迹有效基线的长度与切航迹有效基线的极限长度进行比较以调整所述第一辅星(200)和所述第二辅星(201)的飞行轨迹的短半轴的方式获得，
    所述第三辅星(101)的轨道参数基于方位多普勒解模糊所需要的空间采样的要求以及多普勒解模糊精度的要求获得。
  9. 如前述权利要求之一所述的系统，其特征在于，所述同步装置(400)至少包括时间同步模块(410)、频率同步模块(420)以及空间同步模块(430)，其中，
    所述时间同步模块(410)被配置为：基于开机同时触发产生各星载有的定时脉冲信号并通过星间频率同步脉冲以获得星间的频率差值来实现时间同步。
  10. 如前述权利要求之一所述的系统，其特征在于，所述同步装置(400)中的频率同步模块(420)被配置为：采用线性调频信号作为同步脉冲以周期性的方式交换所述主星(100)与所述第一辅星(200)或第二辅星(201)或第三辅星(101)上的同步脉冲信号处理以获得星上频率源引起的相位差异，从而进行相位补偿以实现频率同步。
  11. 如前述权利要求之一所述的系统，其特征在于，所述同步装置(400)中的空间同步模块(430)被配置为：基于所述主星(100)上的成像传感装置(300)对地面目标区域的指向以及所述第一辅星(200)或第二辅星(201)或第三辅星(101)的卫星姿态以使得所述第一辅星(200)或第二辅星(201)或第三辅星(101)上的成像传感装置(300)指向同一地面目标区域从而完成空间同步。
  12. 一种星载SAR星座系统，其特征在于，包括：以SAR系统为有效载荷的主星(100)、以及至少一对围绕所述主星(100)飞行的第一辅星(200)和第二辅星(201)，其中，
    所述第一辅星(200)和第二辅星(201)围绕所述主星(100)飞行且所述主星(100)位于所述第一辅星(200)和第二辅星(201)的运动轨迹的长轴上以形成具有相同切航迹基线分量的第一空间基线(A)和第二空间基线(B)，其中，
    所述第一辅星(200)和第二辅星(201)关于所述主星(100)成中心对称的方式形成被动的稳定构型以使得所述第一辅星(200)相对所述主星(100)形成第一空间基线(A)，所述第二辅星(201)关于所述主星(100)形成第二空间基线(B)，
    其中，所述第一空间基线(A)与所述第二空间基线(B)长度相同且相位相反。
  13. 如权利要求12所述的系统，其特征在于，所述系统还包括第三辅星(101)，
    所述第三辅星(101)在所述第一辅星(200)和第二辅星(201)的飞行轨道外且与所述主星(100)相邻的轨道上与所述第一主星(100)前后编队飞行，从而相对所述主星(100)形成长沿航迹基线(C)以及短切航迹基线(D)；
    所述SAR系统基于所述第一空间基线(A)和第二空间基线(B)生成长度大于所述短切航迹基线(D)长垂直基线和长度小于所述长沿航迹基线(C)的短水平基线，并结合所述短切航迹基线(D)和长沿航迹基线(C)进行最优干涉信号处理以在高分辨宽测绘带成像的同时提高地形高度测量的精度和量程。
  14. 如权利要求12或13所述的系统，其特征在于，在获得所述主星(100)、第三辅星(101)、第一辅星(200)和第二辅星(201)的轨道参数后，所述主星(100)通过测量装置获取SAR雷达天线姿态参数以对所述主星(100)、第三辅星(101)、第一辅星(200)和第二辅星(201)实现精密定轨来获取高精度的所述第一空间基线(A)、第二空间基线(B)、水平基线(C)以及短切航迹基线(D)，
    其中，所述测量装置至少包括用于姿态测量的GPS接收机，所述GPS接收机执行以下步骤：
    对原始数据进行预处理，主要包括星历数据解码和数据同步；
    通过差分定位算法，获取所述SAR雷达天线的位置参数；
    利用所述SAR雷达天线的位置参数获得整周模糊度的初始值，利用卡尔曼滤波和递归搜索的方法求解出整周模糊度的准确值，并利用载波相位获得精确的坐标；
    利用获得精确坐标值，获得星间基线向量，并通过所述星间基线向量求解得到所述SAR雷达天线的姿态参数。
  15. 一种卫星遥感系统，其特征在于，以SAR系统为有效载荷的主星(100)、第三辅星(101)以及至少一对围绕所述主星(100)飞行的第一辅星(200)和第二辅星(201)，其中，
    在所述主星(100)获得所述SAR雷达天线的姿态参数后，所述GPS接收机基于所述主星(100)、第三辅星(101)、第一辅星(200)和第二辅星(201)的轨道参数并与GPS星座相连接，至少获取日月摄动、太阳光压摄动以及大气阻力摄动的先验信息建立星座系统的轨道扰动模型以消除摄动对基线测量的影响；
    所述GPS接收机基于所述SAR雷达天线的姿态参数以及所述星座系统的轨道扰动模型得到的定轨结果以获得第一空间基线(A)、第二空间基线(B)长沿航迹基线(C)以及短切航迹基线(D)。
PCT/CN2019/121956 2019-08-23 2019-11-29 一种基于卫星编队的遥感系统及星座系统 WO2021036066A1 (zh)

Priority Applications (4)

Application Number Priority Date Filing Date Title
EP19943104.0A EP4020013A4 (en) 2019-08-23 2019-11-29 REMOTE SENSING SYSTEM BASED ON A SATELLITE ARRANGEMENT AND CONSTELLATION SYSTEM
US17/637,744 US11821980B2 (en) 2019-08-23 2019-11-29 Satellite-formation-based remote sensing system and constellation system
CN201980086653.7A CN113439220B (zh) 2019-08-23 2019-11-29 一种基于卫星编队的遥感系统及星座系统
JP2022512772A JP7391429B2 (ja) 2019-08-23 2019-11-29 衛星編隊ベースの遠隔検知システム及びコンステレーションシステム

Applications Claiming Priority (4)

Application Number Priority Date Filing Date Title
CN201910788732.4A CN110456350B (zh) 2019-08-23 2019-08-23 一种星载sar星座系统
CN201910787398.0A CN110488292B (zh) 2019-08-23 2019-08-23 一种基于卫星编队的遥感系统
CN201910788732.4 2019-08-23
CN201910787398.0 2019-08-23

Publications (1)

Publication Number Publication Date
WO2021036066A1 true WO2021036066A1 (zh) 2021-03-04

Family

ID=74683781

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/CN2019/121956 WO2021036066A1 (zh) 2019-08-23 2019-11-29 一种基于卫星编队的遥感系统及星座系统

Country Status (5)

Country Link
US (1) US11821980B2 (zh)
EP (1) EP4020013A4 (zh)
JP (1) JP7391429B2 (zh)
CN (1) CN113439220B (zh)
WO (1) WO2021036066A1 (zh)

Cited By (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN113472417A (zh) * 2021-04-06 2021-10-01 中国科学院空天信息创新研究院 多星编队的雷达定时同步方法、装置、设备及存储介质
CN113900442A (zh) * 2021-10-25 2022-01-07 北京航空航天大学 航天器编队展开重构最优控制求解方法和系统
CN113911398A (zh) * 2021-11-09 2022-01-11 中国人民解放军火箭军工程大学 飞行器单脉冲躲避策略确定方法及系统
CN114844556A (zh) * 2022-04-26 2022-08-02 武昌理工学院 一种基于功能卫星负荷率的遥感信息去差异化传输方法
CN114928417A (zh) * 2022-05-17 2022-08-19 南京邮电大学 一种在摄动影响下基于分布式卫星编队的组阵频谱感知建模分析方法
CN115728766A (zh) * 2022-11-18 2023-03-03 北京卫星信息工程研究所 两级智能双星sar系统与海面舰船目标跟踪方法
CN116148802A (zh) * 2023-04-24 2023-05-23 中国科学院空天信息创新研究院 一种双基sar相位同步抗干扰方法

Families Citing this family (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE102022117088A1 (de) * 2022-07-08 2024-01-11 Deutsches Zentrum für Luft- und Raumfahrt e.V. Verfahren zur Erkennung und Auflösung von Phasenmehrdeutigkeiten in interferometrischen SAR-Daten
CN114910911B (zh) * 2022-07-18 2022-09-30 中国科学院空天信息创新研究院 一种基于多相位中心重构的星载多基sar成像方法
CN116299589B (zh) * 2022-10-20 2024-01-26 极诺星空(北京)科技有限公司 一种星载超小型gnss掩星探测仪
CN115754924B (zh) * 2022-11-18 2023-05-16 北京卫星信息工程研究所 卫星分布式短波雷达系统及空间目标探测方法
CN116859344B (zh) * 2023-08-28 2023-11-03 中国电子科技集团公司第十四研究所 一种面向相干最优的能谱自适应分布式InSAR空间同步方法
CN117056449B (zh) * 2023-10-12 2024-03-12 中国科学院空天信息创新研究院 基于全球网格的卫星数据分景方法、装置、设备及介质
CN117849721B (zh) * 2024-03-07 2024-05-10 银河航天(北京)网络技术有限公司 卫星选择方法及装置

Citations (14)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US6005509A (en) * 1997-07-15 1999-12-21 Deutsches Zentrum Fur Luft-Und Raumfahrt E.V. Method of synchronizing navigation measurement data with S.A.R radar data, and device for executing this method
CN104297751A (zh) 2014-10-20 2015-01-21 西安电子科技大学 一种分布式卫星sar系统的主辅sar图像融合方法
CN107064935A (zh) * 2017-06-13 2017-08-18 中国科学院电子学研究所 一种星载sar系统及其构建方法
CN107395309A (zh) 2017-07-25 2017-11-24 西南电子技术研究所（中国电子科技集团公司第十研究所） 基于星间链路的高精度相对测距与时间同步方法
CN108053416A (zh) 2017-12-14 2018-05-18 北京市遥感信息研究所 一种基于单幅卫星图像的最大储油量提取系统
CN108120981A (zh) 2017-12-27 2018-06-05 中科卫星应用德清研究院 浅海水深雷达遥感探测方法
CN108557114A (zh) 2018-04-18 2018-09-21 上海微小卫星工程中心 一种分布式遥感卫星
CN109164448A (zh) * 2018-08-01 2019-01-08 北京空间飞行器总体设计部 一种主辅星分布式sar侦测一体化成像卫星系统
CN109560862A (zh) * 2019-01-23 2019-04-02 长沙天仪空间科技研究院有限公司 一种基于编队卫星的星间通信系统及方法
CN110377047A (zh) * 2019-06-03 2019-10-25 上海航天控制技术研究所 一种双星卫星编队防碰撞方法
CN110456350A (zh) * 2019-08-23 2019-11-15 长沙天仪空间科技研究院有限公司 一种星载sar星座系统
CN110456349A (zh) * 2019-08-23 2019-11-15 长沙天仪空间科技研究院有限公司 基于分布式合成孔径雷达的动目标检测系统
CN110488292A (zh) * 2019-08-23 2019-11-22 长沙天仪空间科技研究院有限公司 一种基于卫星编队的遥感系统
CN110488293A (zh) * 2019-08-23 2019-11-22 长沙天仪空间科技研究院有限公司 一种非均匀空间构型的分布式sar系统

Family Cites Families (23)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
BE793727A (fr) * 1972-01-07 1973-07-05 Philips Nv Systeem voor de overdracht van datasignalen met behulp van lineaire frequentiemodulatie
US4472720A (en) * 1980-03-24 1984-09-18 Reesor Thomas W Area navigational system using geosynchronous satellites
EP0164142B1 (de) * 1984-05-02 1991-03-27 Koninklijke Philips Electronics N.V. Verfahren und Anordnung zur Ermittlung einer Kernmagnetisierungsverteilung in einem Teil eines Körpers
US5810297A (en) * 1996-04-29 1998-09-22 Basuthakur; Sibnath Satellite cluster attitude/orbit determination and control system and method
DE10132723B4 (de) * 2001-07-05 2006-03-30 Deutsches Zentrum für Luft- und Raumfahrt e.V. Satellitenkonfiguration zur interferometrischen und/oder tomografischen Abbildung der Erdoberfläche mittels Radar mit synthetischer Apertur (SAR)
KR100387136B1 (ko) * 2001-07-06 2003-06-12 주식회사 네비콤 위성항법시스템 및 그를 이용한 항체의 자세측정방법
DE10160399B4 (de) * 2001-12-10 2004-05-27 Deutsches Zentrum für Luft- und Raumfahrt e.V. Flugzeug- oder satellitengestütztes tomographisches Radarverfahren mit synthetischer Apertur
US6781540B1 (en) * 2003-02-21 2004-08-24 Harris Corporation Radar system having multi-platform, multi-frequency and multi-polarization features and related methods
US8768622B2 (en) * 2012-09-14 2014-07-01 The United States Of America, As Represented By The Secretary Of The Navy System and method for maneuver plan for satellites flying in proximity using apocentral coordinate system
ITTO20121117A1 (it) * 2012-12-20 2014-06-21 Thales Alenia Space Italia S P A C On Unico Socio Innovativo design orbitale per missioni spaziali di osservazione della terra
US9743373B2 (en) * 2012-12-28 2017-08-22 Trimble Inc. Concurrent dual processing of pseudoranges with corrections
US9880286B2 (en) * 2012-12-28 2018-01-30 Trimble Inc. Locally measured movement smoothing of position fixes based on extracted pseudoranges
US9910158B2 (en) * 2012-12-28 2018-03-06 Trimble Inc. Position determination of a cellular device using carrier phase smoothing
WO2014171988A2 (en) * 2013-01-29 2014-10-23 Andrew Robert Korb Methods for analyzing and compressing multiple images
CA3122468C (en) * 2013-10-07 2023-10-17 Google Llc Smart-home hazard detector providing non-alarm status signals at opportune moments
WO2016136189A1 (ja) * 2015-02-25 2016-09-01 日本電気株式会社 Ｓａｒデータ検索装置、方法および記録媒体
US9919813B2 (en) * 2015-04-15 2018-03-20 The United States Of America, As Represented By The Secretary Of The Navy Control system and method for a plane change for satellite operations
JP6452586B2 (ja) * 2015-10-07 2019-01-16 三菱電機株式会社 画像処理装置および画像処理方法
EP3355079B8 (en) * 2017-01-25 2023-06-21 Airbus Defence and Space GmbH Method for each of a plurality of satellites of a secondary global navigation satellite system in a low earth orbit
JP6828193B2 (ja) * 2017-06-14 2021-02-10 ビーエイイー・システムズ・インフォメーション・アンド・エレクトロニック・システムズ・インテグレイション・インコーポレーテッド 合成開口を介した雨および運動の衛星トモグラフィ
CN109031297A (zh) * 2018-08-01 2018-12-18 北京空间飞行器总体设计部 主星位于中心、辅星cartwheel编队的分布式SAR构型
CN109164480B (zh) 2018-10-15 2019-11-19 北京环境特性研究所 一种多次反射红外传感器标定装置及方法
CN111829964B (zh) * 2018-12-29 2023-07-18 长沙天仪空间科技研究院有限公司 一种分布式遥感卫星系统

Patent Citations (14)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US6005509A (en) * 1997-07-15 1999-12-21 Deutsches Zentrum Fur Luft-Und Raumfahrt E.V. Method of synchronizing navigation measurement data with S.A.R radar data, and device for executing this method
CN104297751A (zh) 2014-10-20 2015-01-21 西安电子科技大学 一种分布式卫星sar系统的主辅sar图像融合方法
CN107064935A (zh) * 2017-06-13 2017-08-18 中国科学院电子学研究所 一种星载sar系统及其构建方法
CN107395309A (zh) 2017-07-25 2017-11-24 西南电子技术研究所（中国电子科技集团公司第十研究所） 基于星间链路的高精度相对测距与时间同步方法
CN108053416A (zh) 2017-12-14 2018-05-18 北京市遥感信息研究所 一种基于单幅卫星图像的最大储油量提取系统
CN108120981A (zh) 2017-12-27 2018-06-05 中科卫星应用德清研究院 浅海水深雷达遥感探测方法
CN108557114A (zh) 2018-04-18 2018-09-21 上海微小卫星工程中心 一种分布式遥感卫星
CN109164448A (zh) * 2018-08-01 2019-01-08 北京空间飞行器总体设计部 一种主辅星分布式sar侦测一体化成像卫星系统
CN109560862A (zh) * 2019-01-23 2019-04-02 长沙天仪空间科技研究院有限公司 一种基于编队卫星的星间通信系统及方法
CN110377047A (zh) * 2019-06-03 2019-10-25 上海航天控制技术研究所 一种双星卫星编队防碰撞方法
CN110456350A (zh) * 2019-08-23 2019-11-15 长沙天仪空间科技研究院有限公司 一种星载sar星座系统
CN110456349A (zh) * 2019-08-23 2019-11-15 长沙天仪空间科技研究院有限公司 基于分布式合成孔径雷达的动目标检测系统
CN110488292A (zh) * 2019-08-23 2019-11-22 长沙天仪空间科技研究院有限公司 一种基于卫星编队的遥感系统
CN110488293A (zh) * 2019-08-23 2019-11-22 长沙天仪空间科技研究院有限公司 一种非均匀空间构型的分布式sar系统

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
See also references of EP4020013A4

Cited By (11)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN113472417A (zh) * 2021-04-06 2021-10-01 中国科学院空天信息创新研究院 多星编队的雷达定时同步方法、装置、设备及存储介质
CN113900442A (zh) * 2021-10-25 2022-01-07 北京航空航天大学 航天器编队展开重构最优控制求解方法和系统
CN113911398A (zh) * 2021-11-09 2022-01-11 中国人民解放军火箭军工程大学 飞行器单脉冲躲避策略确定方法及系统
CN113911398B (zh) * 2021-11-09 2023-11-10 中国人民解放军火箭军工程大学 飞行器单脉冲躲避策略确定方法及系统
CN114844556A (zh) * 2022-04-26 2022-08-02 武昌理工学院 一种基于功能卫星负荷率的遥感信息去差异化传输方法
CN114844556B (zh) * 2022-04-26 2023-08-25 武昌理工学院 一种基于功能卫星负荷率的遥感信息去差异化传输方法
CN114928417A (zh) * 2022-05-17 2022-08-19 南京邮电大学 一种在摄动影响下基于分布式卫星编队的组阵频谱感知建模分析方法
CN114928417B (zh) * 2022-05-17 2023-06-23 南京邮电大学 一种在摄动影响下基于分布式卫星编队的组阵频谱感知建模分析方法
CN115728766A (zh) * 2022-11-18 2023-03-03 北京卫星信息工程研究所 两级智能双星sar系统与海面舰船目标跟踪方法
CN115728766B (zh) * 2022-11-18 2023-07-25 北京卫星信息工程研究所 两级智能双星sar系统与海面舰船目标跟踪方法
CN116148802A (zh) * 2023-04-24 2023-05-23 中国科学院空天信息创新研究院 一种双基sar相位同步抗干扰方法

Also Published As

Publication number Publication date
EP4020013A1 (en) 2022-06-29
CN113439220B (zh) 2023-10-13
EP4020013A4 (en) 2023-08-23
CN113439220A (zh) 2021-09-24
JP2022546369A (ja) 2022-11-04
US11821980B2 (en) 2023-11-21
US20220283295A1 (en) 2022-09-08
JP7391429B2 (ja) 2023-12-05

Similar Documents

Publication Publication Date Title
WO2021036066A1 (zh) 一种基于卫星编队的遥感系统及星座系统
CN110488292B (zh) 一种基于卫星编队的遥感系统
Rabus et al. The shuttle radar topography mission—a new class of digital elevation models acquired by spaceborne radar
Gray et al. Repeat-pass interferometry with airborne synthetic aperture radar
Rosen et al. Synthetic aperture radar interferometry
Joughin et al. Interferometric estimation of three-dimensional ice-flow using ascending and descending passes
EP2353024B1 (fr) Procede de geo-localisation d'un objet par multitelemetrie
CN110456350B (zh) 一种星载sar星座系统
JPH0772244A (ja) 干渉型合成開口レーダ装置および地形変動観測方式
US6264143B1 (en) Radar interferometry device
Renga et al. Performance of stereoradargrammetric methods applied to spaceborne monostatic–bistatic synthetic aperture radar
Moccia et al. Bistatic synthetic aperture radar
Bamler et al. SRTM and beyond: current situation and new developments in spaceborne InSAR
Chapin et al. Calibration of an across track interferometric P-band SAR
Lee et al. The RADARSAT-2/3 topographic mission
Cramer et al. Data capture
Rohner et al. Multisensor validation of tidewater glacier flow fields derived from sar intensity tracking
Nitti et al. On the use of SAR interferometry to aid navigation of UAV
Hanssen Radar system theory and interferometric processing
Moccia et al. Twin satellite orbital and doppler parameters for global topographic mapping
Chen et al. Space-surface bistatic SAR tomography: a promising approach for accurate local 3D reconstruction
Yu Interferometric synthetic aperture radar and radargrammetry for accurate digital elevation model generation in New South Wales, Australia
Schulze et al. TanDEM-X
CN116559874A (zh) 基于多方位角合成孔径雷达二维海流反演方法及系统
Iwasaki et al. Cross-Track stereovision using aster

Legal Events

Date Code Title Description
121 Ep: the epo has been informed by wipo that ep was designated in this application

Ref document number: 19943104

Country of ref document: EP

Kind code of ref document: A1

ENP Entry into the national phase

Ref document number: 2022512772

Country of ref document: JP

Kind code of ref document: A

NENP Non-entry into the national phase

Ref country code: DE

ENP Entry into the national phase

Ref document number: 2019943104

Country of ref document: EP

Effective date: 20220323