Pulse Interference Suppression Method for Rangefinder Based on Combined Orthogonal Projection and Cyclic Beamforming

Abstract

A rangefinder pulse interference suppression method combining orthogonal projection and cyclic beamforming: the radio frequency signal from the array antenna is converted into an analog baseband signal through the radio frequency front end, and now converted into a digital baseband signal through A / D, and multiple digital The baseband signal is calculated by the orthogonal projection algorithm to obtain the projection matrix of the orthogonal complement space of the interference signal, and acts on the received signal vector to eliminate the interference of the pulse signal of the rangefinder, and further obtains the beamforming weight vector of the array antenna through the cyclic beamforming method, Use it to perform beamforming on the signal vector after the pulse interference is eliminated to extract the OFDM direct path signal; after removing the cyclic prefix, convert it into a frequency domain signal through FFT operation, further down-sample by 4 times the frequency domain, and then estimate the channel characteristics through the channel, Channel equalization is performed through an equalizer, and then an estimated value of the transmitted bit sequence is obtained through a demodulator, a deinterleaver and a decoder in sequence. The invention can effectively overcome the interference of range finder pulse and scattered multipath signals.

Description

technical field [0001] The invention relates to a method for suppressing pulse interference of a range finder. In particular, it relates to a pulse interference suppression method for a rangefinder combined with orthogonal projection and cyclic beamforming. Background technique [0002] In order to ensure the safe, reliable and efficient operation of the new generation air traffic management system of civil aviation, the International Civil Aviation Organization (ICAO) proposed two candidate technical solutions for ground-air data links: L-band Digital Aviation Communication System 1 (L-DACS1) and L-band Digital Aeronautical Communication System 2 (L-DACS2), in which, the L-DACS1 system adopts a multi-carrier Orthogonal Frequency Division Multiplexing (OFDM) transmission scheme, and the L-DACS2 system adopts a single-carrier Gaussian Minimum Frequency Shift Keying (GMSK) transmission scheme . Compared with the L-DACS2 system, the L-DACS1 system has the advantages of higher...

AI Technical Summary

Problems solved by technology

In practical application, this method has the following two problems: the position where the pulse interference signal appears is not easy to determine, and the ICI interference is caused after the pulse is extinguished

There are also two problems in the pulse clipping method: the pulse clipping value is not easy to determine, and the signal still has pulse interference after pulse clipping

However, in the L-band digital aviation communication system 1 (L-DACS1), the pulse interference generated by the range finder is strongly correlated pulse interference, so the compressive sensing method is difficult to be directly applied to the pulse interference suppression of the OFDM system range finder

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