Method for compressing adaptive data-rate original data of satellite-borne SAR (Synthetic Aperture Radar)

Abstract

The invention discloses a method for compressing an adaptive data-rate original data of a satellite-borne SAR (Synthetic Aperture Radar) and relates to a data compression technology. A compression ratio is adaptively selected according to the strength of distributed target echoes on the basis of a BAQ (Block Adaptive Quantization) algorithm. The method comprises the following steps: calculating an amplitude mean value threshold level used for distinguishing the strength of echoes according to known system parameters, performing BAQ compression on a strong echo and directly transmitting a signbit through a weak echo, thereby meeting application requirement while further reducing the data rate; at the coding moment, coding compressed data with different digits according to a sampling pointsequence in turn by taking byte as a unit and confirming the total length of the data after being coded through an in-block amplitude mean value; and at the decoding moment, conforming a data length and a selected compression ratio according to a frame header and auxiliary data and then decoding by using a corresponding Lloyd-Max decoder. The method provided by the invention is used for reducing the data rate and relieving the data transmission pressure of the satellite-borne SAR.

Description

technical field [0001] The present invention relates to the technical field of spaceborne synthetic aperture radar (SAR) original data compression, which is an adaptive data rate spaceborne SAR original data compression method, according to the intensity of distributed target echoes, in the BAQ (Block Adaptive Quantization) algorithm Based on that, the compression ratio is adaptively selected. Under the premise of meeting the application requirements, the data rate can be further reduced, and the data transmission pressure of the spaceborne SAR can be relieved. Background technique [0002] Due to the limited capacity of SAR storage devices and data transmission bandwidth, the original data must first be compressed before being downloaded. Considering the performance of the compression algorithm and the complexity of hardware implementation, the compression algorithms commonly used in engineering are BAQ and FBAQ (Flexible Block AdaptiveQuantization). However, the high-res...

AI Technical Summary

Problems solved by technology

However, for the determination of spaceborne SAR systems, the signal-to-noise ratio of weak echoes is usually low, and the signal-to-noise ratio of the original data compressed with different compression ratios is not much different

Therefore, if the weak echo with a low signal-to-noise ratio is compressed with the same compression ratio as the strong echo, there is a certain degree of redundancy.

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