Phase measurement compensation method for airborne interferometric SAR (synthetic aperture radar) based on synchronous internal calibration signals

Abstract

The invention discloses a phase measurement compensation method for airborne interferometric SAR (synthetic aperture radar) based on synchronous internal calibration signals, effectively improves precision in interchannel error measurement and compensation and lowers the effect of calibration signals on radar performance. A calibration signal source is used to generate a phase modulated internal calibration signal; the phase modulated internal calibration signal is divided into N signals by a shunt, the internal calibration signal is combined with radar echo signal, received by an antenna, through a combiner, the internal calibration signal and the radar echo signal in the same path are synchronously input to corresponding receiving channels by controlling start time of the internal calibration signal; a matching filter is used to extract internal calibration signals from radar data of each receiving channel so as to separate the internal calibration signals from radar echo in an image field; processes of the phases of the receiving channels changing with time is calculated according to phase changes of the internal calibration signals; interchannel phase error measurement and compensation are completed according to phase change processes of the channels, and transmission error correction is complete.

Description

technical field [0001] The invention relates to the technical field of radar information acquisition and processing, in particular to an airborne interferometric SAR phase measurement compensation method based on a synchronous internal calibration signal, which is especially suitable for airborne high-resolution interferometric synthetic aperture radar. Background technique [0002] Multi-channel synthetic aperture radar is an important application of synthetic aperture radar (Synthetic Aperture Radar, SAR), such as spaceborne interferometric SAR, array antenna distributed SAR system. Compared with traditional SAR, its measurement data contains richer target information such as three-dimensional and velocity, and has a wide range of uses in oceanography, glaciology, agriculture and forestry, topographic mapping and military target detection. In order to obtain more analytical information, multi-channel synthetic aperture radar needs to arrange two or more receiving channels....

AI Technical Summary

Problems solved by technology

[0006] The synchronous calibration method based on the point-frequency calibration signal can continuously measure the time-varying phase error between channels by inputting the continuous wave signal in the radar receiving channel as the internal calibration signal, but the point-frequency signal is added to the echo signal, which can only Suppression in the frequency domain destroys the spectral integrity of the radar echo signal, which will affect the interferometric accuracy and other indicators

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