Distributed SAR system with non-uniform spatial configuration

Abstract

The invention relates to a distributed SAR system with a non-uniform spatial configuration. The system comprises a primary satellite and at least one secondary satellite, wherein the primary satellitetakes an SAR system as a payload and forms a non-uniform spatial configuration in a manner that baselines between the primary / secondary satellites are unequal, the main satellite and the auxiliary satellite respectively comprise a baseline preprocessing module and a space-time adaptive processing module, the baseline preprocessing module compensates an echo signal received under a time-varying and / or mixed baselines into an echo signal under the fixed horizontal baseline, before the echo signals received by the main satellite and the auxiliary satellite are compensated by the baseline preprocessing module, the space-time adaptive processing module generates a virtual space uniform sampling signal through a signal reconstruction filter, and a signal-to-clutter-noise ratio of an output signal is maximized through a space-time adaptive processor so as to improve detection probability of a moving target The system is advantaged in that SAR image coherence reduction can be avoided, and thereby clutter suppression performance and speed measurement precision of the space-time adaptive processing module are improved.

Description

technical field [0001] The invention relates to the technical field of radar, in particular to a distributed SAR system with non-uniform spatial configuration. Background technique [0002] The rapid movement of the single-satellite SAR (Synthetic Aperture Radar, SAR) system platform leads to the expansion of clutter, which makes the ground target submerged in the clutter, making it very difficult to detect. This requires the single-satellite SAR system to have a large aperture and multiple antennas when performing Ground Moving Target Indication (GMTI), which is very difficult to realize in engineering. The interval between satellites of the distributed SAR system can be flexibly configured, and a large-aperture antenna can be decomposed into multiple small-aperture antennas, and these small-aperture antennas are placed in each small satellite with a large separation in space. These separated small-aperture antennas are equivalent to a large-aperture antenna through signal...

AI Technical Summary

Problems solved by technology

However, the method provided by this patent only combines the geometric characteristics of the distributed SAR system with non-uniform spatial configuration, but does not take into account the time-varying and mixed baseline characteristics of the non-uniform spatial configuration, that is, the relative position of each satellite changes over time. Constantly changing, the obtained baseline will add a high-order variable factor to the main / auxiliary star SAR image interference result after registration, which is not conducive to the compensation of the background elevation interference phase, resulting in a decrease in the coherence of the SAR image, thereby affecting the clutter Inhibition performance

Moreover, the method provided by this patent does not take into account the interaction between clutter and moving targets

[0006] To sum up, the implementation of GMTI in the existing distributed SAR system is mainly aimed at the situation that the system is in a uniform line array configuration, and it does not take into account that the configuration of the distributed SAR system is difficult to meet the uniform array configuration in actual situations.

However, the existing GMTI implementation methods for non-uniform spatial configurations only take into account the geometric characteristics of non-uniform spatial configurations, but do not take into account the time-varying and mixed characteristics of the baselines between the array elements and the reduction of SAR image coherence. problem, and did not take into account the interaction between clutter and moving targets

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