36 results about "Space-based radar" patented technology

The invention discloses an in-orbit moving target detecting method with space-based radar and infrared data fusion. The method includes the steps that when an infrared detecting system is used for detection, background suppression is carried out on each frame in an infrared image sequence by adopting a filtering method based on the morphology, self-adaptive threshold segmentation is carried out on images obtained after background suppression, a single frame detection result is extracted, a multi-frame target is determined through a tracking algorithm, and whether the detection result is a real target or not is judged to obtain the detection result of the multi-frame target; during radar detection, pulse doppler (PD) is adopted for processing. After time calibration and space calibration are carried out on the obtained infrared and radar target information, data fusion is carried out on the information by adopting a measurement fusion method, and track prediction is carried out on fused data to obtain the estimated position of the target.

The invention discloses a multi-frame coherent TBD method for improving envelope shifting compensation and fractional order Fourier transformation. The multi-frame coherent TBD method comprises the steps of firstly storing multi-frame echo data received by a space-based radar in a data matrix, taking out data in one azimuth unit of each frame one by one, arranging the data together, using the data as target echo data to be processed, calculating distance moving amount of a target in all azimuth units based on space target parameter prior information, shifting the taken echo data to a distance unit according to the calculated distance moving amount, finally conducting phase compensation on the echo data shifted to one distance unit so as to perform fractional order Fourier transformation, using a result obtained through fractional order Fourier transformation to perform constant false-alarm detection processing so as to judge whether the target exists or not. By means of the multi-frame coherent TBD method, a maneuvering target can be effectively detected under the situation of low signal-to-noise ratio, and accordingly the effectiveness of the method is verified.

The invention discloses a high-speed maneuvering target parameter estimation method based on frequency domain polynomial phase transformation. On the basis of data received by a space-based radar, pulse compression processing is carried out on high-speed maneuvering target echo data, fast Fourier transform is carried out along a quick time direction of the data after the pulse compression processing to obtain range frequency domain-slow time data, delaying is carried out on the range frequency domain-slow time data, conjugation of the range frequency domain-slow time data through delaying and the range frequency domain-slow time data without delaying are multiplied to realize frequency domain polynomial phase transformation, inverse fast Fourier transform is carried out along a range frequency domain direction of the data after frequency domain polynomial phase transformation processing, fast Fourier transform is carried out along the slow time direction on the basis to obtain range cell-Dopple data, and finally the range cell-Dopple data are used for target parameter estimation. In the condition of a low signal-to-noise ratio and a limited accumulated pulse number, a high-precision target parameter estimation result is acquired.

The invention provides a dual pulse-repetition frequency ambiguity solving method for space-based radars. The method has the advantages that a speed ambiguity solving process is separated from a distance ambiguity solving process by introducing a dual carrier frequency design for each pulse-repetition frequency, the speed ambiguity is firstly solved by utilizing two different carrier frequencies of a same pulse-repetition frequency and the distance ambiguity is considered to be solved on an one-dimensional distance by utilizing a dual pulse-repetition frequency, so that on the one hand, the pairing problem and the ghost problem existing during the two-dimensional ambiguity solving of an overlap algorithm are alleviated, and on the other hand, the space filling time of the space-based radars is reduced by a large margin and the robustness of the target ambiguity solving is improved.

The invention discloses a space-based radar electromagnetic spectrum environment cognition system and an anti-interference method. According to the method, the space-based radar electromagnetic spectrum environment cognition system is constructed on the basis of a space-based radar, fast beam scanning is performed on a task region continuously by multiple times through the space-based radar electromagnetic spectrum environment cognition system, signals outside a radar signal band range are intercepted from multiple collected signals for spectral analysis, the characteristics of pure interference signals are extracted, and band information of all the interference signals is acquired quickly; and information of the direction of arrival is estimated according to the change of each interference normalization power along with a beam scanning angle, electromagnetic spectrum environment perception prior information is obtained and fed back to the radar system in real time, and consequently the space-based radar system has an anti-interference ability and still maintains a target detection tracking ability even in a complicated electromagnetic environment. Through the method, the characteristics of the pure interference signals can be extracted rapidly, the direction of arrival of interference is estimated, interference information is fed back to the radar system in real time, and theanti-interference function of the system is achieved.

The invention provides a reflecting surface folding and unfolding structure of a foldable and deployable antenna of space-based radar, belongs to the technical field of the space-based radar and solves the problems of existing foldable and deployable antennas. The reflecting surface folding and unfolding structure comprises a reflecting surface, transverse ribs, bistable composite foldable and deployable cylindrical shells and auxiliary unfolding inflatable arms, wherein the reflecting surface is rectangular, the multiple transverse ribs arranged in the width direction of the reflecting surface are mounted on the surface of one side of the reflecting surface, are bonded with the reflecting surface and adopt a hollow tubular structure, the surface, bonded with the reflecting surface, of each transverse rib is a plane, and the surface, opposite to the surface bonded with the reflecting surface, of each transverse rib is an indent arc surface; at least two bistable composite foldable and deployable cylindrical shells are arranged between every two adjacent transverse ribs, and two ends of each bistable composite foldable and deployable cylindrical shell are contacted with the adjacent transverse ribs respectively; the two transverse ribs located on the outmost side of all the transverse ribs are connected through the at least two auxiliary unfolding inflatable arms. The reflecting surface folding and unfolding structure is applied to the space-based radar.

The invention provides a space-based radar efficiency optimization method. The method includes the following steps: determining an inclination angle of a track on the basis of a latitude zone of a target area and the loading distance of space-based radar; calculating the height of the track according to the loading distance of space-based radar and the inclination angle of the track; and arranging multiple space-based radar satellites on the same track surface by enabling the phase angles of the satellites to be equal or arranging the space-based radar satellites on N track surfaces. A zero-degree inclination angle of a non-zero-degree inclination angle of a track can be selected on the basis of a latitude zone of a target area and the loading distance of space-based radar, that is to say, a track with a low inclination angle can be selected. Therefore, the target area can be detected many times and the high system efficiency can be achieved by means of relatively less satellites, and a high temporal resolution detection requirement of an airplane target can be met.

The invention provides a multi-pulse-set optimization design method of a space-based early warning radar, and belongs to the technical field of radar early warning. Various factors including target doppler ambiguity, range clutter ambiguity, range blind areas, space filling time, target range ambiguity resolving and speed ambiguity resolving are fully considered, while reliable target detection isensured, the influence of transmission pulse shielding and sub-satellite point shielding is lowered to the maximum extent, and therefore range ambiguity clutters and range detection blind areas are reduced. Specifically, through the design criteria of the minimum multi-pulse, while reliable target detection is ensured, the influence of transmission pulse shielding and sub-satellite point shielding is lowered to the maximum extent, and therefore the range ambiguity clutters and the range detection blind areas are reduced. The relation between a multi-pulse set and the duty ratio and the protecting window length is restrained, no space and time filling is required during switching of different multi-pulses of the space-based radar, and working efficiency of the radar is greatly improved.

The invention discloses a large-length antenna-oriented containerized storage type on-orbit assembling device and method. A one-way conveying mechanism, a two-way conveying mechanism and an assemblingassembly are fixedly mounted on a supporting frame; each space-based radar board unit is fixedly connected with a one-way conveying mechanism, the one-way conveying mechanisms drive the multiple space-based radar board units to move synchronously, and limiting structures matched with the space-based radar board units are arranged on the one-way conveying mechanisms to limit torsion and shaking ofthe space-based radar board units. The bidirectional conveying mechanism drives the space-based radar board units located at the bottom of the stacked structure to be coplanar with the last but one space-based radar board unit located at the bottom of the stacked structure, or drives the multiple space-based radar board units formed through splicing to move in the opposite direction of the splicing direction. The assembling assembly is used for splicing and fixing the space-based radar board unit located at the bottom of the laminated structure and the last but one space-based radar board unit located at the bottom of the laminated structure into an integral plane structure. The method has the characteristics of simple system composition, expandability, high realizability and the like.

The invention provides a method for connecting a space-based radar antenna reflection surface to a bistable composite material deployable cylindrical shell, belonging to the technical field of space-based radars. The problems of an existing deployable antenna are solved. The method comprises a step of connecting the space-based radar antenna reflection surface to the bistable composite material deployable cylindrical shell by using an aramid rope and aramid cloth, multiple aramid cloth is arranged along the aramid rope and is arranged at two opposite sides of the aramid rope with intervals, the center line positions of the aramid cloth are aligned with the aramid rope, the aramid cloth and the aramid rope are in stitching joint and bonding connection, and the total number of the aramid cloth is odd, wherein aramid cloth in odd number positions is bonded to the reflection, the aramid cloth in even number positions is bonded to the bistable composite material deployable cylindrical shell, and at the same time, the aramid rope is arranged between the aramid cloth in odd number positions and the bistable composite material deployable cylindrical shell. The method is used for the space-based radar antenna reflection surface.

The invention discloses a space-based radar clutter simulation method and device in consideration of terrain height. Abnormal points are rejected through the space-based radar effect distance and earth elevation, and echo suitable for simulating the space-based radar equidistant clutter of any orbit is generated by adopting an iteration computation method. The method disclosed by the invention isin consideration of the influence of an earth sphere model and the earth autorotation, and can be used for the simulation of the space-based radar clutter, the simulation of the space-based radar two-dimensional clutter spectrum, and the evaluation of the space-based radar clutter inhibition method, and further can be used for the space-based radar orbit design.

The invention provides a space-based radar space moving target detection and parameter estimation method and system. The method comprises the steps that S1, radar echoes are preprocessed to obtain baseband echo signals; s2, a corresponding phase compensation function is constructed based on echo characteristics of Doppler ambiguity and Doppler distortion signals so as to eliminate influences of Doppler ambiguity and Doppler spectrum distortion in baseband echo signals at the same time; s3, Keystone transformation is performed on the baseband echo signal subjected to Doppler ambiguity and Doppler distortion elimination to complete linear range walk correction; s4, after distance correction is completed, an acceleration matched filter bank is constructed to eliminate residual distance curvature and Doppler spread; and S5, after range walk and Doppler spread correction are completed, two-dimensional Fourier transform is utilized to complete a final coherent accumulation result. Compared with a traditional Keystone transformation matched filtering method, the provided correction Keystone transformation matched filtering method can achieve coherent integration of the high maneuvering target under the condition that the signal-to-noise ratio is not reduced.

A method is presented for the formation of a constellation of small satellites (smallsats) for radar surveillance employing multiple input, multiple output (MIMO) radar operation. Such a constellation can be used for cost-effective fine angular resolution and persistent remote sensing of targets or regions on, above, and below a planet's surface. Applications include, but are not limited to, surface mapping (including change detection), mapping of meteorological conditions, and detection of fleeting events. The method pertains to satellite configurations whose costs and aggregate masses are much less than those of conventional space-based radar measurements attempting to attain comparable angular resolution, while providing persistent surveillance.

The invention discloses a multi-satellite ultra-short-range flight-following space-borne radar system composed of satellite bodies, a space-borne radar antenna, a high-precision inter-satellite measurement system, an ultra-short-distance flight-following control system, a high-precision planeness measurement system and a big data volume transmission system. Each satellite body is composed of a satellite structure, an attitude control unit, a heat control unit, a power source and a halving system and provides supporting conditions for operation of the radar antenna. According to the invention,through launching multiple small-area radar antenna satellites, ultra-short-range flight following is achieved on track, so that distance and planeness among the antennas are ensured.

The invention discloses a space-based radar distance/speed ambiguity resolution method based on ambiguity matrix updating, which belongs to the technical field of radars. According to the method, a fuzzy matrix is adopted to replace a traditional distance-speed two-dimensional separation ambiguity resolution criterion, the problem of fractional order errors can be avoided in the modes of matrix expansion, element sorting, amplitude variance sorting and element updating, and meanwhile the problem of virtual images caused by multi-target pairing errors and noise pairing can be solved. Under multiple PRF observations, the space-based radar target detection multi-target distance-speed ambiguity resolution is realized, and the occurrence of virtual images can be inhibited. The method has the advantages of being high in operation speed, good in real-time performance and high in anti-noise capacity, can cope with the situation of multi-target or missile defense penetration, and has good engineering application value. The method is especially suitable for ultra-high-speed target detection multi-target distance-speed ambiguity resolution.