36 results about "Space-based radar" patented technology

A space deployable antenna that includes an inflatable envelope, a cylindrical reflector formed on a wall of the envelope, a catenary support frame for maintaining the cylindrical shape of the cylindrical reflector, and a feed array support structure connected to the catenary support frame.

A system and method for determining a position of a target within an acceptable tolerance using an iterative approach. A airborne or space-based measuring device is used to measure an estimated position of the target. The information from the measuring device is used in conjunction with either live captured or stored topography, or the like, information relating to the surface of the planet proximate the target to iteratively determine the actual position of the target.

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.

A method and system are 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 above, below, or upon a planet's surface. Applications include, but are not limited to, surface mapping (including change detection), mapping of meteorological conditions, and monitoring of time-varying events. The method and system pertain to satellite configurations whose costs and aggregate masses are much less than those of traditional space-based radar measurements attempting to attain comparable angular resolution, while also providing intervals of persistent surveillance.

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 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 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 space-based radar system for multi-satellite ultra-short-distance follow-up flight. , large data volume transmission system; the satellite body is composed of satellite structure, attitude control, thermal control, power supply, and other sub-systems, which provide guarantee conditions for the work of the radar antenna. In the present invention, by launching a plurality of small-area radar antenna satellites, an ultra-short-distance follow-up flight is formed on orbit to ensure the distance and flatness between the antennas.

The invention relates to a ground clutter interference real-time suppression method for a space-based external radiation source radar. The ground clutter interference real-time suppression method comprises the steps of: completing key parameter design of a space-based external radiation source radar system according to transmitting and receiving time sequence requirements for system RF signals; analyzing spatial position and moving relation between a space-based radar platform and an external radiation source, and establishing a space-based external radiation source radar ground clutter mathematical model; constructing a reference signal by utilizing a direct wave signal, carrying out cross-correlation processing on the reference signal and a target signal received by a two-channel echo antenna; eliminating ground clutter interference of correlation result of an nth frame signal of a channel 1 and correlation result of an (n-1)th frame signal of a channel 2 by adopting a two-pulse canceller; and repeating the cross-correlation processing and the two-pulse cancelling steps for carrying out Fourier transform on N frame signals after clutter suppression along a speed dimension to achieve phase-coherent accumulation, and adopting a constant false-alarm criterion to realize target detection. The ground clutter interference real-time suppression method can be used for suppressing clutter interference effectively, reduces complexity of the algorithm, and is convenient to achieve real-time data processing of the space-based platform.

The invention discloses a space-based radar distance / velocity defuzzification method based on fuzzy matrix update, which belongs to the technical field of radar. The present invention uses a fuzzy matrix to replace the traditional distance-velocity two-dimensional separation and defuzzification criterion, and can avoid the problem of fractional error by means of matrix expansion, element sorting, amplitude variance sorting and element update, and can solve multi-target pairing errors and problems at the same time. Ghosting issues caused by noisy pairings. Under multiple PRF observations, the present invention realizes multi-target range-velocity defuzzification of space-based radar target detection and can suppress the appearance of ghost images. The invention has the characteristics of fast calculation speed, good real-time performance and strong anti-noise ability, can deal with multi-target or missile penetration situations, and has good engineering application value. The invention is especially suitable for ultra-high-speed target detection and multi-target range-velocity defuzzification.

The invention provides a space-based radar clutter simulation method. The method considers influence of an earth sphere model and earth rotation, through projection and coordinate transformation, the longitude and latitude of equidistant clutter rings on the earth surface can be obtained, clutter Doppler is obtained through coordinate system transformation, and then the reflection power of a clutter unit is calculated, thereby obtaining clutter echoes of equidistant rings. The method can be applied to simulating echoes of space-based radar equidistant clutter rings of any track, and can calculate the positions of the equidistant clutter rings, thereby laying a foundation for determining the clutter type. The method can also be used for space-based radar clutter two-dimensional spectrum analysis, space-based radar clutter suppression method assessment, analysis of influence of a space-based radar track on system performance and the like.

A space-based radar electromagnetic spectrum environment cognition system and interference countermeasure method. A space-based radar electromagnetic spectrum environment cognition system is constructed on the basis of space-based radar. The space-based radar electromagnetic spectrum environment cognition system continuously monitors the mission area for many times. Carry out fast beam scanning, intercept signals outside the frequency band of radar signals for spectrum analysis on the signals collected multiple times, extract the characteristics of pure interference signals, and quickly obtain the frequency band information of all interference signals; according to the normalized power of each interference The change of the beam scanning angle is used to estimate the incoming wave direction information, obtain the prior information of the electromagnetic spectrum environment perception, and feed it back to the radar system in real time, so that the space-based radar system has the ability to resist interference and maintain the ability to detect and track targets in complex electromagnetic environments. The invention can quickly extract the characteristics of the pure interference signal, estimate the incoming wave direction of the interference, feed back the interference information to the radar system in real time, and realize the function of system interference countermeasures.