Method for determining LFM waveform of distributed spaceborne radar based on different frequency modulation slopes of the same bandwidth

Abstract

The invention provides a method for determining an LFM waveform of a distributed spaceborne radar based on different frequency modulation slopes of the same bandwidth. A linear frequency modulation signal of the same carrier frequency, the same time width and the same bandwidth is equally divided into two segments on the time axis, each segment is modulated by using a different frequency modulation slope k, a transmitting signal model of different frequency modulation slopes of the distributed system radar is established to analyze the influence of differences of the frequency modulation slopes on the waveform orthogonality and Doppler sensitivity, autocorrelation, cross-correlation and Doppler tolerance and other parameters of the transmitting waveform are set via theoretical analysis, double-segment transmitting waveform parameters of each radar unit are determined, the quasi-orthogonality and low Doppler sensitivity between multiple double-slope LFM signals are achieved at last, andthe demands of the distributed system radar for the transmitting waveform are met without increasing the bandwidth of the radar system. The method provided by the invention is simple in operation, and can be used for significantly improving the orthogonality of the transmitting waveform of the distributed spaceborne radar system, and reducing the crosstalk between the radar units and the requirements of the distributed system for the system bandwidth B.

Description

technical field [0001] The invention relates to an orthogonal waveform design based on the same bandwidth and different frequency modulation slopes, in particular to a distributed spaceborne radar LFM waveform determination method based on the same bandwidth and different frequency modulation slopes, belonging to the field of microwave remote sensing. Background technique [0002] In the distributed system, due to mutual interference between radars, each spaceborne radar must transmit orthogonal waveforms to make each radar receive target echoes independent of each other, and obtain the time delay and phase information of each radar relative to the target through autocorrelation matching. At the same time, the instability and high-speed motion of the distributed spaceborne radar platform require that the transmitted waveform should be relatively insensitive to Doppler. The traditional method is to achieve waveform orthogonality by frequency division of the transmitted signal...

AI Technical Summary

Problems solved by technology

The traditional method is to achieve waveform orthogonality by frequency division of the transmitted signal, and use the maximum likelihood estimation method to determine the Cramereau threshold of the waveform for analysis. Although the orthogonality of the waveform has been improved and the interference between radars has been reduced, it has greatly Increased bandwidth requirements for formation radar systems

[0003] At present, based on MIMO radar orthogonal frequency division signal design and other methods, a combination of sparse model is proposed to optimize the design of orthogonal discrete frequency LFM waveform, but this method only analyzes the ambiguity function of orthogonal frequency division signal, and the cross-correlation peak The location and amplitude of the lobe level are analyzed, and the method of segmental design of different FM slopes under the same bandwidth condition is not involved. At the same time, this method does not consider and explain the influence of the target Doppler characteristic on the waveform design.

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