Multifunctional digital signal processor for skyborne or spaceborne radar altitude gauge

Abstract

The invention relates to a multifunctional digital signal processor for a skyborne or spaceborne radar altitude gauge, which adopts the technical scheme that an input signal passes through an isolating retainer, and is subjected to sampling through a high-speed A / D sampler under the control of a sequential control unit; a digital I / Q signal is obtained by a digital I / Q processing unit; I / Q data is stored to a data A storage under the control of a storage control unit, and after being stored fully, data of a sub-aperture is processed by a sub-aperture processing unit in a mode of a two-dimensional complex matrix; the output of sub-aperture processing is stored to a data B storage under the control of the storage control unit, and after the data of the sub-aperture is stored fully, subsequent sub-aperture observation data is processed repeatedly and sequentially and is stored to the data B storage continuously; after the data of a set number of the sub-apertures are stored fully, the data is processed by a multi-view processing unit to acquire echo power observation matrixes of resolution footprints in each azimuth finally; and a digital signal processing (DSP) general processor performs maximum likelihood estimation and prediction on each received echo power observation matrix.

Description

technical field [0001] The invention relates to a signal processor for digital signal processing and communication applied to airborne and spaceborne radar altimeters, in particular to a signal processor that satisfies the requirements of sub-aperture altimeters for digital signal processing, can realize multiple working modes, and supports Signal processor for various interface communication. technical background [0002] The radar altimeter is a kind of altimetry radar mounted on aircraft, satellites and other aircrafts, which can be used to measure the average height from the radar to the target surface, target fluctuation characteristics and backscatter coefficient and other parameters. Since its appearance in the 1970s, the spaceborne radar altimeter has played an important role in the observation fields of ocean, sea ice, and land ice with its unique advantages. The spaceborne radar altimeter plays an important role in the measurement of the ocean dynamic environment....

AI Technical Summary

Problems solved by technology

The working principle of various typical traditional altimeters mentioned in the article, the basic structure of its digital signal processor is as follows: Figure 9 As shown, the high-speed A / D sampling and subsequent FFT, digital filtering, and modulus square are mainly completed, and the parameter estimation is obtained through the average echo power to realize the tracking function. None of them perform aperture synthesis on the echo between pulses. Instead, the echo power is obtained by directly calculating the modulus square of it, so that the power utilization efficiency and azimuth resolution cannot be improved by using the correlation between pulses. In the case of large averaging time, there is still a serious pulse-footprint mismatch problem. thus affecting the measurement accuracy

As for the existing DDA system altimeter in the world, in the digital processing part, only non-focus processing is carried out, and at the same time, the compensation problem of space-variable distance migration is not considered, and there are also shortcomings in improving power utilization efficiency and measurement accuracy.

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