Pulse Interference Suppression Method for Rangefinder Based on Joint Doa Estimation and Main Beamforming

Abstract

The invention provides a range finder impulse interference suppression method combining direction of arrival (DOA) estimation and main beam forming. The method comprises the steps that received radio-frequency signals from an array antenna are converted into analog baseband signals; the analog baseband signals are converted into digital baseband signals; the number of the radio-frequency signals and coming-direction information of the radio-frequency signals are analyzed through an estimator; beam forming weights of the coming directions of the digital baseband signals of all the paths are obtained through a linear constraint minimum variance beam forming method, and main beam forming is carried out; orthogonal frequency division multiplexing perpendicular incidence path signals are obtained according to signals, obtained after main beam forming, of all the paths; the Doppler frequency offset values of the received signals are estimated, and Doppler frequency offset compensation is carried out; cyclic prefixes are further removed, conversion is carried out so that frequency domain signals can be obtained, the frequency domain signals are sent to a balancer after being processed through quadruple sampling, signals output by the balancer pass through a demodulator, a deinterleaver and a decoder in sequence so that an estimated value of a sent bit sequence can be obtained. According to the range finder impulse interference suppression method combining DOA estimation and main beam forming, the linear constraint minimum variance beam forming method can be directly utilized for weighting the array-received signals, and range finder impulse signals can be suppressed.

Description

Technical field [0001] The invention relates to a method for suppressing pulse interference of a distance meter. In particular, it relates to a rangefinder pulse interference suppression method that combines DOA estimation and main beamforming. Background technique [0002] In order to ensure the safe, reliable and efficient operation of the new generation of civil aviation air traffic management system, the International Civil Aviation Organization (ICAO) has proposed two candidate technical solutions for ground-to-air data link: L-band digital aviation communication system 1 (L-DACS1) and L-band Digital Aviation Communication System 2 (L-DACS2), of 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 a higher transmission capacity and is mo...

AI Technical Summary

Problems solved by technology

[0003] In terms of research on impulse interference suppression of OFDM receivers in L-DACS1 systems, literature Epple U, Brandes S, Gligorevic S, et al.Receiver optimization for L-DACS1[C] / / Digital AvionicsSystems Conference,2009.DASC'09.IEEE / AIAA 28th.IEEE,2009:4.B.1-1-4.B.1-12. First established the pulse interference model of the rangefinder, and simulated the transmission reliability of the rangefinder to the L-DACS1 system link The research shows that the pulse interference of the rangefinder significantly deteriorates the reliability of the link transmission; and the impact of the pulse extinguishing method on the link error performance of the OFDM receiver is studied. The simulation research shows that the pulse extinguishing method can eliminate the rangefinder to a certain extent. Pulse interference, but pulse extinguishing will lead to inter-subcarrier interference (ICI); for the non-linear inter-subcarrier interference generated by the pulse extinction method, the literature Brandes S, Epple U, Schnell M. Compensation of the impact of interference mitigation by pulse blanking in OFDM systems [C] / / Global Telecommunications Conference, 2009.GLOBECOM 2009.IEEE.IEEE,2009:1-6. and literature Epple U, Shutin D, Schnell M.Mitigation of impulse frequency-selective interference in OFDMbased systems[J].Wireless Communications Letters, IEEE, 2012, 1(5): 484-487. An iterative ICI interference reconstruction and compensation method is proposed. Simulation studies show that the ICI interference reconstruction and compensation method can improve the reliability of the receiver, but the method is complex high accuracy; for the problem of difficult setting of the pulse extinguishing threshold of the pulse extinguishing method, the literature Epple U, Schnell M.Adaptive threshold optimization for a blanking nonlinearity in OFDM receivers[C] / / Global Communications Conference (GLOBECOM), 2012IEEE.IEEE, 2012: 3661-3666. Based on the maximization criterion of signal-to-interference ratio, AWGN channel adaptive pulse quenching is proposed Threshold setting method

The above work is mainly carried out by the German Aerospace Center, which mainly focuses on single-antenna pulse extinguishing, pulse extinguishing ICI interference compensation, and pulse extinguishing threshold setting methods. The proposed method has the following problems in practical applications: (1) Fast time-varying channel In the environment, the pulse extinguishing threshold is not easy to determine; (2) the pulse extinguishing method causes inter-subcarrier interference (ICI), which reduces the reliability of link transmission; (3) ICI interference compensation is difficult and the calculation complexity is high

There are two problems in the application of this method in the actual system: the location of the pulse interference is not easy to determine, and the ICI interference problem is caused after the pulse is extinguished

The main problems of the pulse clipping method: the pulse clipping value is not easy to determine, and the interference problem of the received signal after clipping

Problems with the above methods: It is not easy to determine the pulse extinction threshold, and the complexity of iterative ICI interference reconstruction and compensation calculation is relatively high

Images