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A phase synchronization method for fmcw SAR based on distributed satellites

A phase synchronization and distributed technology, applied in the field of SAR, can solve problems such as phase synchronization, and achieve the effect of improving the accuracy of phase synchronization and the measurement frequency.

Active Publication Date: 2018-06-15
NAT UNIV OF DEFENSE TECH
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Problems solved by technology

[0004] The purpose of the invention is, propose a kind of distributed satellite FMCW SAR phase synchronization method based on signal exchange, solve the phase synchronization problem in the distributed satellite FMCW SAR system

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  • A phase synchronization method for fmcw SAR based on distributed satellites
  • A phase synchronization method for fmcw SAR based on distributed satellites
  • A phase synchronization method for fmcw SAR based on distributed satellites

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Embodiment Construction

[0014] The present invention will be further described below in conjunction with the accompanying drawings.

[0015] figure 1 It is a processing step of the FMCW SAR phase synchronization method based on distributed satellites in the present invention. It is composed of two steps: on-board carrier phase difference extraction and ground carrier phase difference compensation. The first step is real-time extraction through the satellite synchronization signal microwave link Carrier phase difference, the second step compensates the carrier phase difference contained in the echo signal.

[0016] figure 2 It is a schematic diagram of the process of extracting the carrier phase in real time on the satellite, and it shows the process of extracting the carrier phase difference in real time through the microwave link of the synchronization signal on the satellite, which is the first step of phase synchronization.

[0017] Assuming that at any time t, the phase of the output signal of...

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Abstract

The invention provides an FMCW SAR phase synchronization method based on distributed satellites. The method comprises the following steps: at any time t, emission satellite output signals are emitted after being respectively subjected to K frequency multiplication and N frequency multiplication; and then frequency mixing with carrier frequency signals is carried out after M frequency multiplication, and emission-end carrier wave phase differences are obtained through frequency spectrum peak extraction. One path of receiving satellite output signals are subjected to frequency mixing with echo signals after K frequency multiplication, and thus dual-station echo signals are obtained; one path of the receiving satellite output signals are emitted after M frequency multiplication; and one path of the receiving satellite output signals are subjected to frequency mixing with the received emission signals after N frequency multiplication, and receiving-end carrier wave phase differences are obtained through frequency spectrum peak extraction. According to the invention, the emission-end carrier wave phase differences and the receiving-end carrier wave phase differences at any time t can be obtained by use of such a process, and compensation phases of the dual-station echo signals are obtained after difference processing is performed on the emission-end carrier wave phase differences and the receiving-end carrier wave phase differences. According to the invention, the measurement frequency of the carrier wave phase differences can be improved, and the phase synchronization precision is improved.

Description

technical field [0001] The invention belongs to the technical field of SAR (Synthetic Aperture Radar, synthetic aperture radar), in particular to a distributed satellite-based FMCW (Linear Frequency Modulated Continuous Wave, Linear Frequency Modulated Continuous Wave) phase synchronization method. Background technique [0002] Distributed satellite FMCW SAR system is a new space-based radar system combining distributed satellite radar formation and FMCW SAR technology. It has the characteristics of small size, light weight, low cost of data products, and strong rapid response capability. The system transmits FMCW signals and receives echo signals at the same time. Because the satellite platform is far away, unlike the UAV FMCW SAR system, the distributed satellite FMCW SAR system cannot provide sufficient transceiver isolation. The type of configuration will attenuate the transmitted FMCW signal to an appropriate level, and the distance between sending and receiving is usua...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): G01S13/90
CPCG01S13/904G01S13/9058G01S7/4004
Inventor 何志华黄志伟金光虎张启雷董臻张永胜黄海风余安喜何峰孙造宇
Owner NAT UNIV OF DEFENSE TECH
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