A dual-side swing-scan super-wide coverage SAR satellite system, scanning method and device

Abstract

The application discloses a kind of bilateral swingable scanning ultra-wide coverage SAR satellite system, scanning method and device, and relates to spacecraft design field.The application solves the problem that traditional spaceborne SAR is difficult to realize high-resolution wide swath imaging.The application solves the problem that the existing SAR satellite scheme is mostly equipped with a single SAR antenna, and the field of view is expanded by the attitude maneuver of satellite platform.Besides, due to the natural contradiction between resolution and swath, traditional spaceborne SAR is difficult to realize high-resolution wide swath imaging.The system comprises a satellite, a rotating mechanism and two SAR antennas.The two SAR antennas are symmetrically distributed on both sides of the satellite by the rotating mechanism.The method is realized based on the above-mentioned bilateral swingable scanning ultra-wide coverage SAR satellite system, comprising: dividing the scanning area into N distance direction and M azimuth direction sub-bands;the SAR antenna scans according to the divided M sub-bands, and splicing is carried out.The application is applied to the field of satellite monitoring.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of spacecraft design, in particular to a double-sided swingable scanning super-wide coverage SAR satellite system. BACKGROUND

[0002] Synthetic Aperture Radar (SAR) technology has become a core technology of earth observation technology due to its all-weather and all-day operation, and its advantages such as being unaffected by weather such as clouds and fog. Compared with visible light, infrared and other remote sensing methods, SAR has unique advantages and irreplaceable position. At present, SAR has important application value in resource detection, natural disaster monitoring, environmental change, geographic mapping, urban construction and other fields. In recent years, a series of earth observation research programs have been established at home and abroad, which has greatly promoted the vigorous development of SAR technology, and many advanced SAR technologies have emerged. These technologies mainly focus on improving the resolution and increasing the width of the observation field of view. Among them, in order to realize the high-precision, large-scale and time-continuous monitoring and evaluation of the dynamic process of the earth's surface, and to meet the urgent needs of global or regional sustainable development and global change monitoring. Most of the existing SAR satellite schemes only install a single SAR antenna, and expand the field of view through the attitude maneuver of the satellite platform. And because of the natural contradiction between the resolution and the width of the two indicators, it is difficult for traditional satellite-borne SAR to realize high-resolution wide-width imaging. SUMMARY

[0003] The present application solves the problem that most existing SAR satellite schemes only install a single SAR antenna, and expand the field of view through the attitude maneuver of the satellite platform. And because of the natural contradiction between the resolution and the width of the two indicators, it is difficult for traditional satellite-borne SAR to realize high-resolution wide-width imaging.

[0004] The present application provides a double-sided swingable scanning super-wide coverage SAR satellite system, which comprises:

[0005] a satellite, a rotating mechanism and two SAR antennas;

[0006] The two SAR antennas are symmetrically distributed on both sides of the satellite through the rotating mechanism.

[0007] Further, a preferred embodiment is also provided, wherein the SAR antenna adopts a phased array antenna or a ring antenna.

[0008] Further, a preferred embodiment is also provided, wherein the system further comprises a solar panel, which is used to power the satellite system.

[0009] Based on the same inventive concept, the application further provides a scanning method for a bilateral swingable scanning super-wide coverage SAR satellite system, which is realized based on the bilateral swingable scanning super-wide coverage SAR satellite system according to claim 1 and comprises the following steps.

[0010] The scanning area is divided into N distance sub-strips and M azimuth sub-strips.

[0011] The SAR antenna scans according to the M sub-strips and the M sub-strips are spliced.

[0012] Further, a preferred embodiment is further provided, wherein the SAR antenna adopts the DPC-MAB technology for imaging.

[0013] Further, a preferred embodiment is further provided, wherein the scanning mode comprises mechanical mechanical swing scanning and feed scanning.

[0014] Further, a preferred embodiment is further provided, wherein the SAR image is preprocessed.

[0015] The preprocessed SAR image is registered by using the SIFT algorithm to obtain a repeated part of the SAR image.

[0016] The repeated part of the SAR image is smoothed by using a fusion algorithm to obtain a large-scale imaging picture.

[0017] Based on the same inventive concept, the application further provides a scanning device for a bilateral swingable scanning super-wide coverage SAR satellite system, which is realized based on the bilateral swingable scanning super-wide coverage SAR satellite system and comprises the following steps.

[0018] The sub-stripe acquisition unit is used for dividing the scanning area into N distance sub-strips and M azimuth sub-strips.

[0019] The sub-stripe splicing unit is used for scanning the SAR antenna according to the M sub-strips and splicing the scanned M sub-strips.

[0020] Based on the same inventive concept, the application further provides a computer readable storage medium for storing a computer program, wherein the computer program executes the scanning method for the bilateral swingable scanning super-wide coverage SAR satellite system according to any one of the above claims.

[0021] The application further provides a computer device comprising a memory and a processor, wherein the memory stores a computer program, and when the processor runs the computer program stored in the memory, the processor executes the scanning method for the bilateral swingable scanning super-wide coverage SAR satellite system according to any one of the above claims.

[0022] The application has the following advantages:

[0023] The application solves the problem that traditional spaceborne SAR is difficult to realize high-resolution wide swath imaging.

[0024] The double-side swingable scanning ultra-wide coverage SAR satellite system adopts a double-side SAR antenna (a phased array antenna, a feed type antenna or other different types of antennas), can simultaneously image two sides, and has a larger ground coverage range than a conventional SAR satellite which usually only installs a single SAR antenna.

[0025] The scanning method of the double-side swingable scanning ultra-wide coverage SAR satellite system further increases the visible range of the SAR antenna by controlling the side viewing angle of the SAR antenna through a swing mechanism or a feed scanning mechanism.

[0026] The scanning method of the double-side swingable scanning ultra-wide coverage SAR satellite system periodically changes the side viewing angle of the antenna through the swing mechanism, sequentially images each sub-band, and realizes high-resolution wide swath imaging in each sub-band through the double-positioned center azimuth multi-beam (DPC-MAB) technology.

[0027] The application is applied to the field of satellite monitoring. DETAILED DESCRIPTION

[0028] Figure 1 The double-side swingable scanning ultra-wide coverage SAR satellite system according to the second embodiment is shown in the schematic diagram, wherein 1 is a satellite, S21 is a swing mechanism, S22 is a support rod, 3 is a SAR antenna, and 4 is a solar panel.

[0029] Figure 2 The SAR antenna with different side viewing angles according to the eleventh embodiment is shown in the schematic diagram.

[0030] Figure 3 The imaging area splicing schematic diagram according to the eleventh embodiment is shown in the schematic diagram.

[0031] Figure 4 The double-positioned center azimuth multi-beam schematic diagram according to the eleventh embodiment is shown in the schematic diagram. DETAILED DESCRIPTION

[0032] To make the objectives, technical solutions and advantages of the embodiments of the application clearer, the technical solutions in the embodiments of the application will be described below in detail with reference to the drawings in the embodiments of the application. Obviously, the described embodiments are some but not all of the embodiments of the application.

[0033] Embodiment one, the bilateral swingable scanning ultra-wide coverage SAR satellite system, the system comprises:

[0034] Satellite 1, rotating mechanism and two SAR antennas 3;

[0035] The two SAR antennas 3 are symmetrically distributed on both sides of the satellite 1 through the rotating mechanism.

[0036] The bilateral swingable scanning ultra-wide coverage SAR satellite system scanning method of the embodiment can simultaneously image the regions on both sides by using bilateral SAR antennas, and has a larger ground coverage range compared with the existing SAR satellite which is usually provided with a single SAR antenna. In actual application, the simultaneous imaging of the two SAR antennas will cause serious interference problem, therefore, the two SAR antennas 3 are symmetrically distributed on both sides of the satellite 1 through the rotating mechanism, so as to reduce the mutual interference of the antenna imaging beams.

[0037] Embodiment two, see Figure 1 and Figure 2 The embodiment is a further limitation of the bilateral swingable scanning ultra-wide coverage SAR satellite system of the embodiment one, and the SAR antenna 3 adopts a phased array antenna or a ring antenna.

[0038] As shown in Figure 1 , the bilateral swingable scanning ultra-wide coverage SAR satellite system comprises a satellite 1, a SAR antenna 3 and a rotating mechanism. The SAR antenna adopts a phased array antenna or a ring antenna. When the SAR antenna 3 adopts a phased array antenna, the rotating mechanism is a swing scanning mechanism S21, and the phased array antenna is connected with the satellite 1 through the swing scanning mechanism S21, and faces the ground during the on-orbit operation. When the SAR antenna 3 adopts a ring antenna, the rotating mechanism is a support rod S22, and the ring antenna is supported on the satellite through the support rod, and the concave surface of the antenna faces the ground.

[0039] As shown in Figure 2 , Figure 2 The first three figures are schematic diagrams of the side viewing angle of the phased array antenna controlled by the swing scanning mechanism, and the angle of the phased array antenna ranges from 0° to 90°. Figure 2 The last three figures are schematic diagrams of the concave surface of the ring antenna changed by the rotation of the rod, wherein the ring antenna itself does not change, and the support rod connected with the ring antenna rotates around the satellite.

[0040] Embodiment three, the embodiment is a further limitation of the bilateral swingable scanning ultra-wide coverage SAR satellite system of the embodiment one, and the system further comprises a solar panel 4 for supplying power to the satellite system.

[0041] The solar panel absorbs solar energy and converts it into electrical energy to power the satellite system.

[0042] Embodiment four, a scanning method of a dual-side swingable scanning ultra-wide coverage SAR satellite system, the method is implemented based on the dual-side swingable scanning ultra-wide coverage SAR satellite system of embodiment one, comprising:

[0043] The scanning area is divided into N distance sub-strips and M azimuth sub-strips.

[0044] The SAR antenna scans according to the M sub-strips and performs splicing.

[0045] The scanning method of the dual-side swingable scanning ultra-wide coverage SAR satellite system further increases the visible range of the SAR antenna. Compared with the existing SAR satellite, only the swingable scanning mechanism needs to be actuated, and the satellite platform itself does not need to be actuated, which can quickly image the specified area and reduce the energy consumption of the attitude maneuver.

[0046] Embodiment five, referring to Figure 4 This embodiment is a further limitation of the scanning method of the dual-side swingable scanning ultra-wide coverage SAR satellite system of embodiment four, and the SAR antenna uses the DPC-MAB technology for imaging.

[0047] As shown in Figure 4 In each sub-strip, the SAR antenna is configured using the offset phase center azimuth multi-beam DPC-MAB technology, which increases the equivalent azimuth sampling rate by using multiple receiving channels uniformly distributed in the azimuth direction to receive echo signals simultaneously, ensures high-resolution imaging, and uses a lower pulse repetition frequency to improve the imaging swath bandwidth, thereby realizing high-resolution wide-swath imaging.

[0048] The principle is that multiple receiving channels are uniformly distributed in the azimuth direction (satellite motion direction), and each receiving channel receives the beam reflected by the ground after being transmitted by the transmitting channel on the antenna, which equivalently improves the sampling rate in the azimuth direction and improves the resolution in the azimuth direction.

[0049] The scanning method of the dual-side swingable scanning ultra-wide coverage SAR satellite system periodically changes the antenna side view angle through the swingable scanning mechanism, sequentially images each sub-strip, and realizes high-resolution wide-swath imaging in each sub-strip through the offset phase center azimuth multi-beam (DPC-MAB) technology. By splicing each sub-strip, the imaging of the 2000km area on both sides can be realized.

[0050] Embodiment six, referring toFigure 3 The embodiment is described. The embodiment is a further limitation of the scanning method of the dual-side swingable scanning ultra-wide coverage SAR satellite system described in embodiment four, and the scanning method comprises mechanical mechanical swing scanning and feed scanning.

[0051] Specifically, the entire region is divided into N x M (range x azimuth) sub-bands, and in sequence, the (1, 1) sub-band is first aligned by mechanical swing scanning, and then imaged by feed scanning, and then the (2, 1) sub-band is aligned by swing scanning, and then imaged by electrical scanning, and so on until the (N, 1) sub-band. After the imaging of all the sub-bands in the first column in the range direction is completed, the imaging of the sub-bands in the second column is started, starting from the (N, 2) sub-band and ending at the (1, 2) sub-band. In this way, the imaging sequence of the adjacent two columns of sub-bands is exactly opposite, and the first or last sub-band of each column is switched to the corresponding sub-band of the next column.

[0052] Embodiment seven, the embodiment is a further limitation of the scanning method of the dual-side swingable scanning ultra-wide coverage SAR satellite system described in embodiment four, and the splicing comprises:

[0053] preprocessing the SAR image;

[0054] aligning the preprocessed SAR image by using the SIFT algorithm to obtain a repeated part of the SAR image;

[0055] smoothing the repeated part of the SAR image by using a fusion algorithm to obtain a large-scale imaging picture.

[0056] The preprocessing of the SAR image is to reduce the noise spots of the image by filtering.

[0057] Specifically, the embodiment is described in combination with embodiment two. During the in-orbit motion of the satellite platform, the SAR antennas on both sides are turned on to image the earth at the same time, the swing mechanism changes the side viewing angle of the antenna, and the antenna performs periodic scanning along the range direction to form a plurality of sub-bands; in each sub-band, the antenna performs imaging by using the DPCMAB technology; and the imaging results of the sub-bands are processed to form a complete image by splicing and inlaying, so as to realize continuous imaging of the 2000km region on both sides.

[0058] Embodiment eight, the scanning device of the dual-side swingable scanning ultra-wide coverage SAR satellite system described in the embodiment is realized based on the dual-side swingable scanning ultra-wide coverage SAR satellite system described in embodiment one, and the device comprises:

[0059] a sub-band acquisition unit, configured to divide the scanning region into N x M (range x azimuth) sub-bands;

[0060] The sub-band splicing unit is used for scanning by the SAR antenna according to the divided M sub-bands, and splicing the scanned M sub-bands.

[0061] Embodiment nine, a computer readable storage medium according to the embodiment, the computer readable storage medium is used for storing a computer program, the computer program executes the scanning method of the bilateral swingable scanning super wide coverage SAR satellite system according to any one of the embodiments four to five.

[0062] Embodiment ten, a computer device according to the embodiment, comprising a memory and a processor, the memory has stored a computer program, when the processor runs the computer program stored in the memory, the processor executes the scanning method of the bilateral swingable scanning super wide coverage SAR satellite system according to any one of the embodiments four to five.

[0063] The above description of the technical solutions of the present application in combination with the drawings is further described in detail, which is used to highlight the advantages and benefits, and is not used as a limitation of the present application, any modification, combination, improvement and equivalent replacement of the present application based on the principle of the present application should be included in the protection scope of the present application.

Claims

1. A scanning method for a dual-side swingable ultra-wide coverage SAR satellite system, characterized in that: The method is implemented based on a bilaterally swingable ultra-wide coverage SAR satellite system, which includes: a satellite, a rotating mechanism, and two SAR antennas; the two SAR antennas are axially symmetrically distributed on both sides of the satellite via the rotating mechanism; the SAR antennas are phased array antennas or loop antennas; the system also includes solar panels, which are used to power the satellite system; The method comprises: The scanning area is divided into N sub-strips in range and M sub-strips in azimuth; The SAR antenna scans and splices the divided M sub-strips; The scanning methods include mechanical swing scanning and feed scanning, specifically: The entire area is divided into N sub-strips in range and M sub-strips in azimuth. In order, first, mechanically align the (1, 1) sub-strip through scanning and image it through electrical scanning. Then, align the (2, 1) sub-strip through scanning and image it through electrical scanning, and so on until the (N, 1) sub-strip. After imaging all sub-strips in the first column in range, imaging begins in the second column, starting with the (N, 2) sub-strip and continuing to the (1, 2) sub-strip. Similarly, the imaging order of adjacent columns of sub-strips is reversed, switching from the first or last sub-strip in each column to the corresponding sub-strip in the next column. In each sub-strip, the SAR antenna is configured with offset phase center azimuth multi-beam DPC-MAB, which simultaneously receives echo signals by using multiple receiving channels evenly distributed along the azimuth direction.

2. The scanning method of a dual-side swingable ultra-wide coverage SAR satellite system according to claim 1, characterized in that: The splicing includes: Preprocessing of SAR images; Registering the pre-processed SAR image using a SIFT algorithm to obtain a repeated portion of the SAR image; The fusion algorithm is used to smooth the repeated parts of the SAR image to obtain a large imaging picture.

3. A computer-readable storage medium, characterized in that The computer-readable storage medium is used to store a computer program, and the computer program executes the scanning method of a bilaterally swingable ultra-wide coverage SAR satellite system according to any one of claims 1-2.

4. A computer device, characterized in that: The system comprises a memory and a processor, wherein a computer program is stored in the memory. When the processor runs the computer program stored in the memory, the processor executes a scanning method for a bilaterally swingable ultra-wide coverage SAR satellite system according to any one of claims 1 to 2.

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