CN114488135A - Low-orbit small satellite distributed GNSS-S radar system and in-orbit processing method - Google Patents

Low-orbit small satellite distributed GNSS-S radar system and in-orbit processing method Download PDF

Info

Publication number
CN114488135A
CN114488135A CN202210314938.5A CN202210314938A CN114488135A CN 114488135 A CN114488135 A CN 114488135A CN 202210314938 A CN202210314938 A CN 202210314938A CN 114488135 A CN114488135 A CN 114488135A
Authority
CN
China
Prior art keywords
satellite
gnss
radar
processing
information
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Granted
Application number
CN202210314938.5A
Other languages
Chinese (zh)
Other versions
CN114488135B (en
Inventor
夏正欢
金世超
刘新
岳富占
彭涛
王海涛
梁银川
赵志龙
张瑶
张闯
高文宁
徐振兴
张涛
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Beijing Institute of Satellite Information Engineering
Original Assignee
Beijing Institute of Satellite Information Engineering
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
Application filed by Beijing Institute of Satellite Information Engineering filed Critical Beijing Institute of Satellite Information Engineering
Priority to CN202210314938.5A priority Critical patent/CN114488135B/en
Publication of CN114488135A publication Critical patent/CN114488135A/en
Application granted granted Critical
Publication of CN114488135B publication Critical patent/CN114488135B/en
Active legal-status Critical Current
Anticipated expiration legal-status Critical

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
    • G01S13/88—Radar or analogous systems specially adapted for specific applications
    • 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
    • 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
    • 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
    • G01S19/14—Receivers specially adapted for specific applications
    • 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
    • G01S19/35—Constructional details or hardware or software details of the signal processing chain
    • G01S19/37—Hardware or software details of the signal processing chain

Landscapes

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

Abstract

The invention relates to a low-orbit small satellite distributed GNSS-S radar system and an in-orbit processing method, wherein the system comprises: the main satellite (50) is used for receiving, capturing and tracking navigation satellite signals in a detection area, receiving and processing GNSS-S echo signals of sea surface ship targets, and performing fusion processing on distributed GNSS-S radar information; and the secondary satellites (10, 20, 30, 40) are used for receiving, acquiring and tracking navigation satellite signals in the detection area and receiving and processing GNSS-S echo signals of the sea surface ship targets. The invention has the advantages of high imaging detection performance, high information timeliness, strong self concealment, low system power consumption, low system cost and the like.

Description

Low-orbit small satellite distributed GNSS-S radar system and in-orbit processing method
Technical Field
The invention relates to a low-orbit small satellite distributed GNSS-S radar system and an in-orbit processing method.
Background
Search detection and high-resolution imaging of sea surface ship targets are always hot spots of scientific research, but due to weather influences such as sea cloud, rain, fog and the like, the satellite-borne optical camera is difficult to exert the advantages of high-resolution imaging identification. The satellite-borne Synthetic Aperture Radar (SAR) can penetrate through clouds and fog, has all-weather observation capability all day long, and can realize high-resolution imaging detection of sea surface ship targets, but the existing SAR is difficult to realize tracking monitoring of the ship targets. When the GNSS-S is used for target detection, active signal emission is not needed, and target detection can be realized only by receiving a scattered signal of a navigation satellite signal, so that the GNSS-S has the advantage of low power consumption, has the advantage of long-time work compared with a large-power-consumption SAR, and is more suitable for tracking and monitoring a ship target. In addition, the navigation satellite signal also has the advantage of global coverage, and any space on the sea surface can receive a plurality of navigation satellite signals simultaneously, so that the multi-station combined detection advantage is achieved.
In this regard, some technologies propose to realize sea surface wind field detection by using a reflection signal (GNSS-R) of a navigation satellite signal, and to complete a low-earth-orbit satellite carrying test. Meanwhile, other technologies propose to realize satellite-to-ground dual-station SAR imaging by using a scattered signal (GNSS-S) of a navigation satellite signal on a foundation, but are limited by the effective bandwidth of the navigation satellite signal, and the imaging resolution is generally in the order of ten meters. Moreover, the satellite-borne GNSS-S radar is limited by the low power of the navigation satellite signals, and can effectively receive the echo signals of the sea surface ship targets by a large-caliber antenna, which is generally tens of square meters in caliber, so that the satellite can be carried by a medium-sized or large-sized satellite, and further, the large-scale popularization and application of the satellite-borne GNSS-S radar can be limited. Therefore, how to use a plurality of low-orbit small satellites to form a distributed GNSS-S radar to reduce the aperture of a receiving antenna of each small satellite and ensure the detection performance of a ship target becomes a problem to be solved in the field.
Disclosure of Invention
The invention aims to provide a low-orbit small satellite distributed GNSS-S radar system and an on-orbit processing method.
In order to achieve the above object, the present invention provides a low-earth orbit small satellite distributed GNSS-S radar system and an on-orbit processing method, the system comprising:
the main satellite is used for receiving, capturing and tracking navigation satellite signals in a detection area, receiving and processing GNSS-S echo signals of a ship target on the sea surface, and performing fusion processing on distributed GNSS-S radar information;
the secondary satellite is used for receiving, capturing and tracking navigation satellite signals in a detection area and receiving and processing GNSS-S echo signals of a ship target on the sea surface.
According to one aspect of the invention, the master satellite and the slave satellite are both provided with a GNSS-S radar receiver, and the GNSS-S radar receiver can receive a direct signal transmitted by a navigation satellite, extract time synchronization information and frequency synchronization information, and receive an echo signal of a sea surface target to realize detection and imaging of the sea surface target.
According to one aspect of the invention, the GNSS-S radar receiver comprises:
the small-caliber phased array antenna is used for receiving, capturing and tracking a navigation satellite direct signal, the beam direction of the antenna is upward, and the polarization mode of the antenna is dextrorotationCircularly polarized and simultaneously operated at fc1And fc2Two frequency bands, fc1Is 1.575GHz, fc2At 1.268GHz, the antenna gain G1 is greater than 10 dB;
the large-aperture phased array antenna is used for receiving sea surface ship target echo signals, the antenna beam direction is downward in side view, the antenna polarization mode is vertical linear polarization and horizontal linear polarization, and the large-aperture phased array antenna simultaneously works at fc1And fc2In two frequency bands, the antenna gain G2 is more than 35 dB;
the radar electronics system is used for receiving, sampling and quantizing, on-orbit processing, on-orbit storage and information transmission of navigation satellite direct signals and sea surface GNSS-S echo signals;
the small-aperture phased array antenna and the large-aperture phased array antenna are both only used for receiving.
According to one aspect of the invention, the radar electronics system comprises:
the double-channel direct wave receiver is used for amplifying and sampling two paths of GNSS direct signals output by the small-caliber phased array antenna to obtain two paths of digital domain direct signals, and the nth frequency band 1 direct signal and the nth frequency band 2 direct signal received from the satellite are recorded asZ 1,n(k) And Z2,n(k) (ii) a Wherein k is a sampling time sequence;
a four-channel echo signal receiver, configured to amplify and sample and quantize four paths of GNSS-S echo signals output by the large-aperture phased array antenna to obtain four paths of digital domain GNSS-S echo signals, and count that the nth horizontally polarized echo signal of frequency band 1, vertically polarized echo signal of frequency band 1, horizontally polarized echo signal of frequency band 2, and vertically polarized echo signal of frequency band 2 received from a satellite are SH,1,n(k)、sV,1,n(k)、sH,2,n(k)、sV,2,n(k) And are all continuous wave signals; wherein, the lower corner mark H represents a horizontal polarization echo signal; with the lower corner mark V representing the vertically polarized echo signal;
the radar main control unit is used for controlling a signal receiving and sampling quantization time sequence, a data storage time sequence, a signal and information processing time sequence and an information transmission time sequence;
the data storage unit is used for performing on-orbit storage on the navigation satellite direct signal, the GNSS-S echo signal and the target radar image slice;
the frequency source unit is used for outputting three clocks simultaneously, wherein two clocks are respectively output to the two-channel direct wave receiver and the four-channel echo signal receiver to serve as sampling frequencies, the frequency is 100MHz-125MHz, the time synchronization error of the two is less than 500ps, and the other clock is output to the radar main control unit to serve as an on-orbit processing working frequency, and the frequency is 200MHz-250 MHz;
the signal and information processing unit is used for preprocessing the GNSS-S echo signal, performing multi-source radar imaging, detecting a ship target and extracting a slice image;
and the information transmission unit is used for carrying out inter-planet transmission and information interaction on the distributed GNSS-S radar information.
According to one aspect of the invention, GNSS-S radar signal and information processing of a single satellite (i.e. a master satellite/slave satellite, also called a distributed single node) is completed on N +1 satellites at the same time, and the process comprises:
respectively aligning four echo signals s by using reference code signals of M navigation satellites extracted by direct signalsH,1,n(k)，sV,1,n(k)，sH,2,n(k)，sV,2,n(k) Performing matched filtering processing, generating M echo signals, respectively denoted as sH,1,n,m(k)，sV,1,n,m(k)，sH,2,n,m(k)，sV,2,n,m(k) Wherein N is 1,2, and N, M is 1,2, and M; m is the serial number of M navigation satellites;
respectively converting 4M echo signals into 4M two-dimensional echo signals which are recorded as s according to M navigation satellite positions and low-orbit satellite positions extracted by using direct signalsH,1,n,m(p,q)，sV,1,n,m(p,q)，sH,2,n,m(p,q)，sV,2,n,m(p, q), wherein p and q represent a slow-time sampling sequence and a fast-time sampling sequence, respectively;
carrying out double-station radar imaging processing on the 4M two-dimensional echo signals respectively by utilizing a back projection imaging algorithm to obtain 4M double-station radar images, and recording the 4M radar images of the nth slave satellite as follows:
RH,1,n,m(α,β)，RV,1,n,m(α,β)，RH,2,n,m(α,β)，RV,2,n,m(α,β)；
wherein alpha and beta respectively represent an azimuth space grid sequence and a distance space grid sequence of the same detection region from the ground plane;
fusing two polarized images of the same navigation satellite and the same frequency band to obtain 2M dual-polarized fused images, and recording the 2M images of the nth satellite after the dual-polarized fusion processing of the two frequency bands as
Figure BDA0003568744570000041
Wherein the content of the first and second substances,
Figure BDA0003568744570000051
Figure BDA0003568744570000052
wH,1,n,m、wV,1,n,m、wH,2,n,m、wV,2,n,mall the polarization information are polarization information fusion processing weights;
("Upper horizontal line" indicates the image after the fusion process, i.e., distinguished from the previous unfused image)
Fusing the polarization fusion images of the same navigation satellite and different frequency bands to obtain M images after dual-band dual-polarization fusion, and recording the M images after the dual-band dual-polarization fusion of the nth slave satellite as
Figure BDA0003568744570000053
Then there are:
Figure BDA0003568744570000054
wherein, w1,n,mAnd w2,n,mRespectively as a dual-band information fusion siteManaging the weight value;
performing fusion processing on the multi-dimensional fusion images of different navigation satellites to obtain a multi-dimensional information fusion image, and recording the multi-dimensional information fusion image of the nth slave satellite as
Figure BDA0003568744570000055
Then there is
Figure BDA0003568744570000056
Wherein, wn,mProcessing the weight for the multi-dimensional information fusion;
image of nth slave satellite
Figure BDA0003568744570000057
Carrying out ship target detection and slice image extraction, and recording the image slice of the jth ship target as In,j(αj,βj) Wherein J is 1,2jAnd betajRespectively taking 2-3 times of the length of the ship target for the azimuth grid point sequence and the distance grid point sequence of the jth ship target slice image, wherein J is the number of the ship targets in the detection area.
According to one aspect of the invention, the distributed information fusion process is completed on the main satellite, and the process comprises the following steps:
carrying out fusion processing on the distributed GNSS-S radar image of the ship target;
according to image Ij(αj,βj) Calculating the length L of the jth ship targetjWidth WjAnd aspect ratio gammajAnd classifying the ship target and outputting the type of the ship target.
According to one aspect of the invention, N slice images I of the jth ship target obtained from the satellite are processed in a fusion processn,j(αj,βj) Slice image I acquired with primary satellite0,j(αj,βj) Performing distributed information fusion processing to obtain radar image recorded as I after distributed information fusion processingj(αj,βj) Then there is
Figure BDA0003568744570000061
Wherein, cnAnd c0Respectively, distributed multi-star information fusion weight, I0,j(αj,βj) And the j-th ship target slice image is processed by multi-dimensional information fusion for the main satellite.
According to one aspect of the invention, the orbit height is H, the main satellite is in front, N auxiliary satellites are 50-100km behind the main satellite, and the N auxiliary satellites follow the main satellite in a flying around formation mode; the wave beams of the large-aperture phased array antenna all point to the same detection area so as to simultaneously obtain distributed GNSS-S echo signals of the same detection area, and the detection area is simultaneously irradiated by M navigation satellites; the N slave satellites only carry out data and information interaction with the main satellite through inter-satellite links respectively; each satellite is provided with an in-orbit processing hardware system which can perform in-orbit processing on a plurality of GNSS-S echo signals and information; the host satellite may transmit the information processed by the distributed GNSS-S radar to a ground station or other application (e.g., a relay communication satellite).
An on-orbit processing method, comprising the steps of:
a. acquiring and tracking a navigation satellite direct signal, and performing matched filtering processing on a GNSS-S echo signal;
b. performing double-station radar imaging and multi-dimensional radar image fusion processing on the 4M echo signals;
c. and carrying out ship target detection and slice image extraction on the fused radar image.
According to an aspect of the present invention, in step (a), four pieces of FPGA (field programmable gate array) are used to perform matched filtering processing on the horizontal polarization echo signal of frequency band 1, the vertical polarization echo signal of frequency band 1, the horizontal polarization echo signal of frequency band 2, and the vertical polarization echo signal of frequency band 2;
in the step (b), eight FPGAs are used for respectively carrying out double-station radar imaging and multi-dimensional image fusion processing on the 4M echo signals;
and (c) carrying out ship target detection and slice image extraction on the fused radar image by using a piece of FPGA.
According to the conception of the invention, a low-orbit small satellite distributed GNSS-S radar system and an in-orbit processing method are provided, the system consists of N +1 small satellites, 1 is a main satellite, and N are auxiliary satellites, so that cooperative in-orbit processing is formed, each small satellite carries the same GNSS-S radar receiver, and simultaneously acquires multi-dimensional information of the same detection area, so that space distributed cooperative detection is realized, the caliber of a GNSS-S echo signal receiving antenna required by each satellite is reduced, and engineering realization and wide application are facilitated. Each GNSS-S radar receiver is provided with two pairs of phased array antennas, one pair of small-caliber phased array antennas is used for capturing and tracking navigation satellite signals, and the other pair of large-caliber phased array antennas is used for receiving sea surface ship target echo signals. The large-aperture phased array antennas of the GNSS-S radar receivers of the N +1 satellites all point to the same detection area, and distributed echo signals in the same detection area are synchronously received. Each small satellite respectively carries out preprocessing and multi-source radar imaging on the received echo signals, after target in-orbit detection, image slice extraction and other processing, target images (namely target slice image information) of N slave satellites are transmitted to a main satellite, and N +1 radar images of the target are subjected to distributed information fusion processing and ship target classification on the main satellite to obtain radar images with higher signal-to-noise ratio, so that in-orbit processing of distributed GNSS-S radar signals and information is realized, ship target detection performance is improved, target images SCNR are improved, target contour information is enhanced, in-orbit processing timeliness of the distributed GNSS-S radar information is improved, and multi-satellite link information transmission pressure is reduced. Therefore, the low-orbit small satellite distributed GNSS-S radar system and the in-orbit processing method have the advantages of high imaging detection performance, high information timeliness, strong self concealment, low system power consumption, low system cost and the like, and have high application value and wide market application prospect.
Drawings
FIG. 1 is a diagram schematically illustrating a low-earth-orbit small satellite distributed GNSS-S radar system according to an embodiment of the present invention;
FIG. 2 is a diagram schematically illustrating a detection scenario of a low-earth-orbit small satellite distributed GNSS-S radar system according to an embodiment of the present invention;
FIG. 3 is a schematic representation of a single GNSS-S radar receiver component of one embodiment of the present invention;
FIG. 4 is a schematic representation of a single-satellite GNSS-S radar signal and information processing flow diagram in accordance with an embodiment of the present invention;
FIG. 5 is a flow diagram that schematically illustrates a distributed information fusion process, in accordance with an embodiment of the present invention;
FIG. 6 schematically shows a functional block diagram of an on-track processing method according to an embodiment of the present invention.
Detailed Description
In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the embodiments will be briefly described below. It is obvious that the drawings in the following description are only some embodiments of the invention, and that for a person skilled in the art, other drawings can be derived from them without inventive effort.
The present invention is described in detail below with reference to the drawings and the specific embodiments, which are not repeated herein, but the embodiments of the present invention are not limited to the following embodiments.
Referring to fig. 1, the low-earth-orbit small satellite distributed GNSS-S radar system of the present invention can be used for high-resolution wide-range SAR imaging, and is suitable for key technical research of space-based distributed high-resolution wide-range SAR systems, and the system includes: the main satellite 50 is used for receiving, capturing and tracking navigation satellite signals in a detection area, receiving and processing GNSS-S echo signals of a ship target on the sea surface, and performing fusion processing on distributed GNSS-S radar information; the slave satellites 10, 20, 30, 40 (i.e. the slave satellite 1, the slave satellite 2, the slave satellite N-1, and the slave satellite N) are used for receiving, acquiring and tracking navigation satellite signals in an exploration area and receiving and processing GNSS-S echo signals of a sea surface ship target.
Referring to fig. 2, the low-earth-orbit small satellite distributed GNSS-S radar system has an orbit height H, and is composed of N +1 small satellites, 1 of which is a master satellite 50 and N of which are slave satellites, the master satellite 50 is in front, the N slave satellites are 50-100km behind the master satellite 50, and the N slave satellites follow the flight in a winding flight formation manner; the wave beams of the large-aperture phased array antennas of the GNSS-S radar receivers of the N +1 satellites all point to the same detection area so as to obtain distributed GNSS-S echo signals of the same detection area at the same time; the detection area is simultaneously irradiated by M navigation satellites; the main satellite 50 performs data interaction and information interaction with the N auxiliary satellites respectively by utilizing inter-satellite links, and the inter-satellite information and data interaction between the N auxiliary satellites does not occur, so that the distributed radar system is simplified; each small satellite (i.e. the master satellite 50 and the slave satellites 10, 20, 30 and 40) is provided with the same GNSS-S radar receiver, each GNSS-S radar receiver can receive a direct signal transmitted by a navigation satellite, extract time synchronization information and frequency synchronization information, and simultaneously receive an echo signal of a sea surface target, so as to realize detection and imaging of the sea surface target; each satellite is provided with an in-orbit processing hardware system for carrying out in-orbit processing and ship target detection classification on a plurality of GNSS-S echo signals and information; the main satellite is responsible for transmitting the information processed by the distributed GNSS-S radar to a ground station or other application systems (such as a relay communication satellite).
Referring to fig. 3, the GNSS-S radar receiver includes: the small-aperture phased array antenna 101 is used for receiving, capturing and tracking a navigation satellite direct signal, the antenna beam points upwards, the antenna polarization mode is right-hand circular polarization, the antenna simultaneously works in two frequency bands, and the central frequency is respectively recorded as fc1And fc2，fc1Is 1.575GHz, fc2At 1.268GHz, the antenna gain G1 is greater than 10 dB; the large-aperture phased array antenna 102 is used for receiving sea surface ship target echo signals, the antenna beam direction is downward in side view, the antenna polarization mode is vertical line polarization and horizontal line polarization, and the large-aperture phased array antenna simultaneously works in two frequency bands (the same is f)c1And fc2) Antenna gain G2 is greater than 35 dB; the two phased array antennas only have receiving components and no transmitting components; a radar electronics system 103 for receiving, sampling and quantizing, on-orbit processing, on-orbit storage and signal transmission of navigation satellite direct signals and sea surface GNSS-S echo signalsAnd (5) information transmission. Wherein the radar electronics system 103 comprises: a dual-channel direct wave receiver 1031, configured to amplify and sample and quantize two paths of GNSS direct signals output by the small-aperture phased array antenna 101 to obtain two paths of digital domain direct signals, and record that the nth frequency band 1 direct signal and the nth frequency band 2 direct signal received from the satellite are Z direct signals respectively1,n(k) And Z2,n(k) Wherein k is a sampling time sequence; a four-channel echo signal receiver 1032, configured to amplify and sample and quantize four paths of GNSS-S echo signals output by the large-aperture phased array antenna 102 to obtain four paths of digital domain GNSS-S echo signals, and record that the nth horizontally polarized echo signal of frequency band 1, vertically polarized echo signal of frequency band 1, horizontally polarized echo signal of frequency band 2, and vertically polarized echo signal of frequency band 2 received from a satellite are SH,1,n(k)，sV,1,n(k)，sH,2,n(k)，sV,2,n(k) And the four echo signals are continuous wave signals, wherein the echo signal with the lower corner mark H represents a horizontal polarization echo signal; with the lower corner mark V representing the vertically polarized echo signal; a radar main control unit 1033 for controlling a signal receiving and sampling quantization timing sequence, a data storage timing sequence, a signal and information processing timing sequence, and an information transmission timing sequence; a data storage unit 1034 for performing on-orbit storage on the navigation satellite direct signal, the GNSS-S echo signal, the target radar image slice, and the like; the frequency source unit 1035 is used for outputting three clocks at the same time, the clock 1 and the clock 2 are respectively output to the two-channel direct wave receiver 1031 and the four-channel echo signal receiver 1032 to be used as sampling frequencies which are 100MHz-125MHz, the time synchronization error of the two is less than 500ps, and the clock 3 is output to the radar main control unit 1033 to be used as an on-track processing working frequency which is 200MHz-250 MHz; a signal and information processing unit 1036, configured to perform preprocessing, multi-source radar imaging, ship target detection, slice image extraction, and the like on the GNSS-S echo signal; and the information transmission unit 1037 is used for inter-satellite transmission and information interaction of the distributed GNSS-S radar information.
Referring to fig. 4, the GNSS-S radar signal and information processing of a single satellite (distributed single node) mainly includes GNSS-S echo signal preprocessing, multi-source radar imaging, target on-orbit detection, target image slice extraction processing, and specificallyThe process comprises the following steps: performing matched filtering processing 201, namely performing matched filtering processing on the GNSS-S echo signals, specifically, respectively performing four-path echo signals S by using reference code signals of M navigation satellites extracted by the direct signalH,1,n(k)，sV,1,n(k)，sH,2,n(k)，sV,2,n(k) Performing matched filtering processing to generate M echo signals respectively denoted as sH,1,n,m(k)，sV,1,n,m(k)，sH,2,n,m(k)，sV,2,n,m(k) Wherein N is 1,2, and N, M is 1,2, and M is the serial number of M navigation satellites; m double-station radar imaging processes 202, that is, two-dimensional timing recovery and double-station radar imaging are performed on M echo signals, specifically, 4M echo signals are converted into 4M two-dimensional echo signals, which are recorded as s, by using M navigation satellite positions and low-orbit satellite positions extracted from a direct signalH,1,n,m(p,q)，sV,1,n,m(p,q)，sH,2,n,m(p,q)，sV,2,n,m(p, q), wherein p and q represent a slow-time sampling sequence and a fast-time sampling sequence, respectively; up to this point, the matched filtering process may be referred to as GNSS-S echo signal preprocessing. Simultaneously, still carry out multisource radar formation of image, specifically include: respectively carrying out double-station radar imaging processing on the 4M two-dimensional echo signals by utilizing a Back Projection (BP) imaging algorithm to obtain 4M double-station radar images, and recording the 4M radar images of the nth slave satellite as RH,1,n,m(α,β)，RV,1,n,m(α,β)，RH,2,n,m(α,β)，RV,2,n,m(α, β), wherein α and β represent an azimuth space grid sequence and a range space grid sequence of the same detection region from the ground plane, respectively; the dual-polarization image fusion 203 is to respectively perform fusion processing on two polarization images of the same navigation satellite and the same frequency band to obtain 2M dual-polarization fusion images, and record the 2M images of the nth slave satellite after the dual-polarization fusion processing of the two frequency bands as
Figure BDA0003568744570000111
Wherein the content of the first and second substances,
Figure BDA0003568744570000112
Figure BDA0003568744570000113
wH,1,n,m、wV,1,n,m、wH,2,n,m、wV,2,n,mall the polarization information are polarization information fusion processing weights;
the dual-band image fusion 204 is to respectively perform fusion processing on polarization fusion images of the same navigation satellite and different frequency bands to obtain M images after dual-band dual-polarization fusion processing, and to record the M images after the dual-band dual-polarization fusion processing of the nth slave satellite as
Figure BDA0003568744570000121
Then there are:
Figure BDA0003568744570000122
wherein, w1,n,mAnd w2,n,mRespectively carrying out dual-band information fusion processing weights; the multi-dimensional image fusion processing 205 is to perform fusion processing on the multi-dimensional fusion images of different navigation satellites respectively to obtain a multi-dimensional information fusion image, and the multi-dimensional information fusion image of the nth slave satellite is recorded as
Figure BDA0003568744570000123
Then there is
Figure BDA0003568744570000124
Wherein, wn,mProcessing the weight for the multi-dimensional information fusion; object detection and slice extraction 206, i.e. images of the nth slave satellite
Figure BDA0003568744570000125
Carrying out ship target detection and slice image extraction, and recording the image slice of the jth ship target as In,j(αj,βj) Wherein J is 1,2jAnd betajRespectively the orientation of the jth ship target slice imageAnd taking the length of the ship target 2-3 times of the length of the ship target from the grid point sequence and the distance grid point sequence, wherein J is the number of the ship targets in the detection area. In the invention, the GNSS-S radar signal of a single satellite and the information processing are simultaneously completed on N +1 satellites.
Referring to fig. 5, the process flow of the distributed (multi-satellite) information fusion only on the primary satellite 50 includes: the distributed GNSS-S radar image fusion process 301 is to perform fusion process on the distributed GNSS-S radar image of the ship target to improve the SCNR, specifically, to obtain N slice images I of the jth ship target from N satellitesn,j(αj,βj) Slice image I acquired with the primary satellite 500,j(αj,βj) Performing distributed information fusion processing to obtain radar image recorded as I after distributed information fusion processingj(αj,βj) Then there is
Figure BDA0003568744570000126
Wherein, cnAnd c0For distributed multi-star information fusion weight, I0,j(αj,βj) A slice image of the jth ship target after the multi-dimensional information fusion processing is performed on the main satellite 50; ship object classification 302, i.e. from image Ij(αj,βj) Calculating the length L of the jth ship targetjWidth WjAnd aspect ratio gammajAnd classifying the ship target and outputting the type of the ship target.
Referring to fig. 6, in the on-orbit processing method of the present invention, first, a signal preprocessing FPGA401 is used to capture and track a navigation satellite direct signal, and perform matched filtering processing on a GNSS-S echo signal, specifically, four FPGAs (i.e., FPGAs 1-A, FPGA1-B, FPGA1-C, FPGA1-D) are used to perform matched filtering processing on a horizontal polarization echo signal of a frequency band 1, a vertical polarization echo signal of a frequency band 1, a horizontal polarization echo signal of a frequency band 2, and a vertical polarization echo signal of a frequency band 2, respectively. Then, the multi-source radar imaging FPGA402 is used for carrying out double-station radar imaging and multi-dimensional radar image fusion processing on the 4M echo signals, and 8 FPGAs are contained in total. Finally, the fused radar image is subjected to ship target detection and slice image extraction by using the target detection FPGA403, and 1 FPGA is contained.
In summary, the distributed GNSS-S radar system and the in-orbit processing method for low-orbit microsatellites of the present invention utilize a plurality of microsatellites to respectively carry a GNSS-S receiver and simultaneously acquire multi-dimensional information of the same detection area, thereby realizing spatially distributed cooperative detection, reducing the aperture of a receiving antenna required by each satellite, and facilitating engineering implementation and wide application. And by adopting a cooperative on-orbit processing method of a master satellite and a slave satellite, each satellite respectively performs signal preprocessing, multi-source radar imaging, target on-orbit detection, image slice extraction and the like, target slice image information is transmitted to the master satellite, and distributed information fusion processing is performed on the master satellite, so that the target image SCNR is improved, the on-orbit processing timeliness is improved, and the information transmission pressure among the satellites is reduced. Therefore, the low-orbit small satellite distributed GNSS-S radar system and the in-orbit processing method have the advantages of high imaging performance, high information timeliness, strong self concealment, low system power consumption, low system cost and the like.
The above description is only one embodiment of the present invention, and is not intended to limit the present invention, and it is apparent to those skilled in the art that various modifications and variations can be made in the present invention. Any modification, equivalent replacement, or improvement made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims (10)

1. A low-earth-orbit small satellite distributed GNSS-S radar system, comprising:
the main satellite (50) is used for receiving, capturing and tracking navigation satellite signals in a detection area, receiving and processing GNSS-S echo signals of a ship target on the sea surface, and fusing distributed GNSS-S radar information;
and the slave satellites (10, 20, 30, 40) are used for receiving, acquiring and tracking navigation satellite signals in the detection area and receiving and processing GNSS-S echo signals of the ship targets on the sea surface.
2. The system according to claim 1, wherein the master satellite (50) and the slave satellites (10, 20, 30, 40) are each equipped with a GNSS-S radar receiver that can receive direct signals transmitted from navigation satellites, extract time synchronization information and frequency synchronization information, and receive echo signals of sea surface targets to detect and image the sea surface targets.
3. The system of claim 2, wherein the GNSS-S radar receiver comprises:
the small-aperture phased array antenna (101) is used for receiving, capturing and tracking a navigation satellite direct signal, the antenna beam points upwards, the antenna polarization mode is right-hand circular polarization, and the small-aperture phased array antenna works at fc1And fc2Two frequency bands, fc1Is 1.575GHz, fc2At 1.268GHz, the antenna gain G1 is greater than 10 dB;
the large-aperture phased array antenna (102) is used for receiving sea surface ship target echo signals, the antenna beam direction is downward in side view, the antenna polarization mode is vertical linear polarization and horizontal linear polarization, and the large-aperture phased array antenna works at f simultaneouslyc1And fc2In two frequency bands, the antenna gain G2 is more than 35 dB;
the radar electronics system (103) is used for receiving, sampling and quantizing, on-orbit processing, on-orbit storage and information transmission of navigation satellite direct signals and sea surface GNSS-S echo signals;
the small-aperture phased array antenna (101) and the large-aperture phased array antenna (102) are both used for receiving only.
4. The system according to claim 3, characterized in that the radar electronics system (103) comprises:
a dual-channel direct wave receiver (1031) for amplifying and sampling the two paths of GNSS direct signals output by the small-caliber phased-array antenna (101) to obtain two paths of digital domain direct signals, and recording the Nth band 1 direct signal and the band 2 direct signal received from the satellite as Z direct signals respectively1,n(k) And Z2,n(k) (ii) a Where k is the sampling timeA sequence;
a four-channel echo signal receiver (1032) for amplifying and sampling the four paths of GNSS-S echo signals output by the large-aperture phased array antenna (102) to obtain four paths of digital domain GNSS-S echo signals, and recording the S-th horizontal polarization echo signal of frequency band 1, the vertical polarization echo signal of frequency band 1, the horizontal polarization echo signal of frequency band 2 and the vertical polarization echo signal of frequency band 2 received from the satellite as SH,1,n(k)、sV,1,n(k)、sH,2,n(k)、sV,2,n(k) And are all continuous wave signals;
the radar main control unit (1033) is used for controlling a signal receiving and sampling quantization time sequence, a data storage time sequence, a signal and information processing time sequence and an information transmission time sequence;
the data storage unit (1034) is used for performing on-orbit storage on the navigation satellite direct signal, the GNSS-S echo signal and the target radar image slice;
the frequency source unit (1035) is used for outputting three clocks at the same time, wherein two clocks are respectively output to the two-channel direct wave receiver (1031) and the four-channel echo signal receiver (1032) to serve as sampling frequencies, the frequency is 100MHz-125MHz, the time synchronization error of the two clocks is less than 500ps, and the other clock is output to the radar main control unit (1033) to serve as an on-orbit processing working frequency, and the frequency is 200MHz-250 MHz;
the signal and information processing unit (1036) is used for preprocessing GNSS-S echo signals, multi-source radar imaging, ship target detection and slice image extraction;
and the information transmission unit (1037) is used for inter-satellite transmission and information interaction of the distributed GNSS-S radar information.
5. The system of claim 1, wherein the distributed single-node GNSS-S radar signal and information processing is performed on N +1 satellites simultaneously, and the process comprises:
respectively aligning four echo signals s by using reference code signals of M navigation satellites extracted by direct signalsH,1,n(k)，sV,1,n(k)，sH,2,n(k)，sV,2,n(k) To carry out the process ofMatched with filtering processing, each signal generates M echo signals which are respectively marked as sH,1,n,m(k)，sV,1,n,m(k)，sH,2,n,m(k)，sV,2,n,m(k) Wherein N is 1,2, and N, M is 1,2, and M; m is the serial number of M navigation satellites;
respectively converting 4M echo signals into 4M two-dimensional echo signals which are recorded as s according to M navigation satellite positions and low-orbit satellite positions extracted by using direct signalsH,1,n,m(p,q)，sV,1,n,m(p,q)，s H,2,n,m(p,q)，sV,2,n,m(p, q), wherein p and q represent a slow-time sampling sequence and a fast-time sampling sequence, respectively;
carrying out double-station radar imaging processing on the 4M two-dimensional echo signals respectively by utilizing a back projection imaging algorithm to obtain 4M double-station radar images, and recording the 4M radar images of the nth slave satellite as follows:
RH,1,n,m(α,β)，RV,1,n,m(α,β)，RH,2,n,m(α,β)，RV,2,n,m(α,β)；
wherein alpha and beta respectively represent an azimuth space grid sequence and a distance space grid sequence of the same detection region from the ground plane;
fusing two polarized images of the same navigation satellite and the same frequency band to obtain 2M dual-polarized fused images, and recording the 2M images of the nth satellite after the dual-polarized fusion processing of the two frequency bands as
Figure FDA0003568744560000031
Wherein the content of the first and second substances,
Figure FDA0003568744560000032
Figure FDA0003568744560000033
wH,1,n,m、wV,1,n,m、wH,2,n,m、wV,2,n,mfusion of polarization informationProcessing the weight value;
fusing the polarization fusion images of the same navigation satellite and different frequency bands to obtain M images after dual-band dual-polarization fusion, and recording the M images after the dual-band dual-polarization fusion of the nth slave satellite as
Figure FDA0003568744560000041
Then there are:
Figure FDA0003568744560000042
wherein, w1,n,mAnd w2,n,mRespectively carrying out dual-band information fusion processing weights;
performing fusion processing on the multi-dimensional fusion images of different navigation satellites to obtain a multi-dimensional information fusion image, and recording the multi-dimensional information fusion image of the nth slave satellite as
Figure FDA0003568744560000043
Then there is
Figure FDA0003568744560000044
Wherein, wn,mProcessing the weight for the multi-dimensional information fusion;
for the nth image of the slave satellite
Figure FDA0003568744560000045
Carrying out ship target detection and slice image extraction, and recording the image slice of the jth ship target as In,j(αj,βj) Wherein J is 1,2jAnd betajRespectively taking 2-3 times of the length of the ship target for the azimuth grid point sequence and the distance grid point sequence of the jth ship target slice image, wherein J is the number of the ship targets in the detection area.
6. The system of claim 1, wherein the distributed information fusion process is performed at the primary satellite (50) and comprises:
carrying out fusion processing on the distributed GNSS-S radar image of the ship target;
according to image Ij(αj,βj) Calculating the length L of the jth ship targetjWidth WjAnd aspect ratio gammajAnd classifying the ship target and outputting the type of the ship target.
7. The system of claim 6, wherein N slice images I of a jth ship target obtained from a satellite are processed during the fusion processn,j(αj,βj) Slice image I acquired with a primary satellite (50)0,j(αj,βj) Performing distributed information fusion processing to obtain radar image recorded as I after distributed information fusion processingj(αj,βj) Then there is
Figure FDA0003568744560000046
Wherein, cnAnd c0Respectively, distributed multi-star information fusion weight, I0,j(αj,βj) The slice image of the j-th ship target is processed by the main satellite (50) through multi-dimensional information fusion.
8. The system of claim 1, wherein the orbital altitude is H, the master satellite (50) is in front, N slave satellites are 50-100km behind the master satellite (50), and the N slave satellites follow in a fly-around formation; the wave beams of the large-aperture phased array antenna (102) all point to the same detection area so as to simultaneously obtain distributed GNSS-S echo signals of the same detection area, and the detection area is simultaneously irradiated by M navigation satellites; the N slave satellites only carry out data and information interaction with the main satellite (50) through inter-satellite links respectively; each satellite is provided with an in-orbit processing hardware system which can perform in-orbit processing on a plurality of GNSS-S echo signals and information; the host satellite (50) may transmit the distributed GNSS-S radar processed information to a ground station or a relay communication satellite.
9. An on-orbit processing method using the low-orbit small satellite distributed GNSS-S radar system of any one of claims 1 to 8, comprising the steps of:
a. acquiring and tracking a navigation satellite direct signal, and performing matched filtering processing on a GNSS-S echo signal;
b. performing double-station radar imaging and multi-dimensional radar image fusion processing on the 4M echo signals;
c. and carrying out ship target detection and slice image extraction on the fused radar image.
10. The method according to claim 9, wherein four FPGAs are used in step (a) to perform matched filtering processing on the frequency band 1 horizontal polarization echo signal, the frequency band 1 vertical polarization echo signal, the frequency band 2 horizontal polarization echo signal, and the frequency band 2 vertical polarization echo signal;
in the step (b), eight FPGAs are used for respectively carrying out double-station radar imaging and multi-dimensional image fusion processing on the 4M echo signals;
and (c) carrying out ship target detection and slice image extraction on the fused radar image by using a piece of FPGA.
CN202210314938.5A 2022-03-28 2022-03-28 Low-orbit small satellite distributed GNSS-S radar system and in-orbit processing method Active CN114488135B (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
CN202210314938.5A CN114488135B (en) 2022-03-28 2022-03-28 Low-orbit small satellite distributed GNSS-S radar system and in-orbit processing method

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
CN202210314938.5A CN114488135B (en) 2022-03-28 2022-03-28 Low-orbit small satellite distributed GNSS-S radar system and in-orbit processing method

Publications (2)

Publication Number Publication Date
CN114488135A true CN114488135A (en) 2022-05-13
CN114488135B CN114488135B (en) 2023-03-07

Family

ID=81487743

Family Applications (1)

Application Number Title Priority Date Filing Date
CN202210314938.5A Active CN114488135B (en) 2022-03-28 2022-03-28 Low-orbit small satellite distributed GNSS-S radar system and in-orbit processing method

Country Status (1)

Country Link
CN (1) CN114488135B (en)

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN114966690A (en) * 2022-06-10 2022-08-30 北京航空航天大学 GNSS-R SAR double-satellite fusion imaging method and system
CN115657034A (en) * 2022-12-29 2023-01-31 北京九天微星科技发展有限公司 Wide swath imaging method and system
CN115755051A (en) * 2022-11-18 2023-03-07 北京卫星信息工程研究所 Distributed on-orbit processing method and system for double-satellite high-resolution wide-amplitude SAR (synthetic aperture radar) signals
CN117289256A (en) * 2023-11-24 2023-12-26 成都本原星通科技有限公司 Target long-distance high-precision tracking method based on low-orbit communication satellite

Citations (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN103414508A (en) * 2013-08-14 2013-11-27 大连大学 Method for establishing communication links between master-and-slave satellites
CN107656246A (en) * 2017-08-18 2018-02-02 上海无线电设备研究所 A kind of space-based air-sea moving-target wide area detection system
WO2021094740A1 (en) * 2019-11-13 2021-05-20 Airbus Defence And Space Limited Maritime surveillance radar
CN113009521A (en) * 2021-03-02 2021-06-22 北京航空航天大学 Aerial target detection device based on GNSS forward scattering characteristic
CN113253267A (en) * 2019-08-23 2021-08-13 长沙天仪空间科技研究院有限公司 Satellite-borne radar
CN113472417A (en) * 2021-04-06 2021-10-01 中国科学院空天信息创新研究院 Radar timing synchronization method, device, equipment and storage medium for multi-satellite formation
CN114019456A (en) * 2021-10-14 2022-02-08 航天恒星科技有限公司 Micro-nano satellite networking radar system for space target detection
CN114137516A (en) * 2021-10-29 2022-03-04 上海埃依斯航天科技有限公司 Marine environment monitoring system based on stay track end sub-level cluster

Patent Citations (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN103414508A (en) * 2013-08-14 2013-11-27 大连大学 Method for establishing communication links between master-and-slave satellites
CN107656246A (en) * 2017-08-18 2018-02-02 上海无线电设备研究所 A kind of space-based air-sea moving-target wide area detection system
CN113253267A (en) * 2019-08-23 2021-08-13 长沙天仪空间科技研究院有限公司 Satellite-borne radar
WO2021094740A1 (en) * 2019-11-13 2021-05-20 Airbus Defence And Space Limited Maritime surveillance radar
CN113009521A (en) * 2021-03-02 2021-06-22 北京航空航天大学 Aerial target detection device based on GNSS forward scattering characteristic
CN113472417A (en) * 2021-04-06 2021-10-01 中国科学院空天信息创新研究院 Radar timing synchronization method, device, equipment and storage medium for multi-satellite formation
CN114019456A (en) * 2021-10-14 2022-02-08 航天恒星科技有限公司 Micro-nano satellite networking radar system for space target detection
CN114137516A (en) * 2021-10-29 2022-03-04 上海埃依斯航天科技有限公司 Marine environment monitoring system based on stay track end sub-level cluster

Non-Patent Citations (3)

* Cited by examiner, † Cited by third party
Title
鞠丞: "星载SAR模糊函数和动目标检测研究", 《中国优秀硕士学位论文全文数据库信息科技辑》 *
马驭飞等: "面向卫星导航信号的外辐射源雷达软件化模拟器设计", 《电讯技术》 *
齐雅男: "星载GNSS-R海面目标探测技术研究", 《中国优秀硕士学位论文全文数据库信息科技辑》 *

Cited By (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN114966690A (en) * 2022-06-10 2022-08-30 北京航空航天大学 GNSS-R SAR double-satellite fusion imaging method and system
CN114966690B (en) * 2022-06-10 2024-05-03 北京航空航天大学 GNSS-R SAR double-star fusion imaging method and system
CN115755051A (en) * 2022-11-18 2023-03-07 北京卫星信息工程研究所 Distributed on-orbit processing method and system for double-satellite high-resolution wide-amplitude SAR (synthetic aperture radar) signals
CN115755051B (en) * 2022-11-18 2023-07-25 北京卫星信息工程研究所 Double-star high-resolution wide SAR signal distributed on-orbit processing method and system
CN115657034A (en) * 2022-12-29 2023-01-31 北京九天微星科技发展有限公司 Wide swath imaging method and system
CN115657034B (en) * 2022-12-29 2023-09-01 北京九天微星科技发展有限公司 Wide swath imaging method and system
CN117289256A (en) * 2023-11-24 2023-12-26 成都本原星通科技有限公司 Target long-distance high-precision tracking method based on low-orbit communication satellite
CN117289256B (en) * 2023-11-24 2024-01-30 成都本原星通科技有限公司 Target long-distance high-precision tracking method based on low-orbit communication satellite

Also Published As

Publication number Publication date
CN114488135B (en) 2023-03-07

Similar Documents

Publication Publication Date Title
CN114488135B (en) Low-orbit small satellite distributed GNSS-S radar system and in-orbit processing method
CA3067604C (en) System and method for widespread low cost orbital satellite access
CN101980048B (en) Antenna array forming technology-based ground-based radar system for space debris
US20200341152A1 (en) Symmetrical Multistatic Radar Constellation for Earth Observation
CN103744080A (en) Satellite-borne multi-channel synthetic aperture radar imaging device
WO2019196445A1 (en) Satellite-borne multiband one-dimensional synthetic aperture and one-dimensional real aperture microwave radiation detection method
CN114637004B (en) Satellite-borne GNSS-S multi-station radar on-orbit processing and ship information fusion system and method
CN107422321B (en) Microwave staring associated imaging ground observation method
CN113671537B (en) Three-frequency beacon signal ionosphere channel simulation method
CN106597442A (en) Orientation multi-channel intra-pulse bunching SAR imaging method
Okada et al. System design of wide swath, high resolution, full polarimietoric L-band SAR onboard ALOS-2
CN114488134B (en) Satellite-borne multi-channel GNSS-S radar video imaging system and ship track extraction method
Pisanu et al. Upgrading the Italian BIRALES system to a pulse compression radar for space debris range measurements
Parker et al. Development of an interoperable GNSS space service volume
CN115754338A (en) Multi-satellite cooperative GNSS-R sea surface vector wind field detection system and on-orbit inversion method
Motohka et al. Overview of alos-2 and alos-4 l-band sar
CN114509754A (en) Satellite-borne multi-channel GNSS-S radar mass data on-orbit processing system and method
Suzuki et al. Development status of PALSAR-2 onboard ALOS-2
CN112584308A (en) Unmanned aerial vehicle cluster over-the-horizon networking device and method based on Beidou system
Borisenkov et al. Bistatic P-band SAR for spacecraft AIST-2
Suzuki et al. Overview of Japan's advanced land observing satellite-2 mission
Suzuki et al. Overview of ALOS-2 and ALOS-3
Sanad et al. Statistical Classification of Remote Sensing Satellite Constellations
Jędrzejewski et al. First experimental trials of passive DVB-T based space object detection with a single LOFAR radio telescope
Arikawa et al. Development status of Japanese advanced land observing satellite-2

Legal Events

Date Code Title Description
PB01 Publication
PB01 Publication
SE01 Entry into force of request for substantive examination
SE01 Entry into force of request for substantive examination
GR01 Patent grant
GR01 Patent grant