Single-frequency and multi-frequency GNSS signal narrow-band interference suppression devices, systems and methods

Abstract

The invention discloses single-frequency and multi-frequency GNSS signal narrow-band interference suppression devices, systems and methods, wherein the multi-frequency GNSS signal narrow-band interference suppression system comprises at least one pre-processing module, at least one cache processing module, at least one cache control module, at least one delay module, a multiplexing module, a windowing processing module, a FFT calculation module, a NBI filter processing module, an IFFT calculation module, a demultiplexing module, at least one overlapped processing module and a time division multiplexing control module. According to the single-frequency and multi-frequency GNSS signal narrow-band interference suppression devices, systems and methods in the invention, narrow-band interferencesuppression on single-frequency and multi-frequency GNSS signals can be carried out; the suppression effect is good; furthermore, the hardware resource cost and the system power consumption can be reduced; and the practicability is relatively high.

Description

technical field [0001] The invention relates to the technical field of satellite navigation digital signal processing, in particular to a single-frequency and multi-frequency GNSS signal narrowband interference suppression device, system and method thereof. Background technique [0002] Global Navigation Satellite System (GNSS) signals provide all-weather, real-time, continuous high-precision position information, speed and time information around the world, and play an increasingly important role in people's lives. [0003] GNSS signals adopt spread spectrum communication technology, which has strong anti-interference ability, and its anti-interference ability is determined by the spread spectrum processing gain and bandwidth. However, in actual communication, the anti-interference ability of spread spectrum communication is limited due to the limitation of signal transmission power, equipment implementation cost and the cost of increasing bandwidth. The GNSS signal arrivi...

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Problems solved by technology

[0006] The first method is a simple interference suppression technology based on FFT / IFFT. The GNSS signal is output after windowing processing, FFT calculation, NBI filtering processing and IFFT calculation. Although this method can remove narrow-band interference, the windowing processing is reducing Spectrum leakage during FFT prevents interference from spreading to other frequency points, and at the same time causes distortion of the input signal, resulting in a loss of the signal-to-noise ratio of the output signal.

[0007] The second method is based on the interference suppression technology of OFFT (Overlapped Fast Fourier Transform, superimposed Fast Fourier Transform). On the basis of the first method, the GNSS signal is divided into two channels, which are respectively delayed by 1 / 2FFT block length And without delay, windowing, FFT, interference frequency removal, and IFFT are performed independently, and then combined according to a certain algorithm. This method has the advantages of easy design and can filter out multiple narrowband interferences at the same time, but it requires 4 FFTs (2 FFT modules and 2 IFFT modules) engine, the hardware implementation complexity is high, and the frequency resolution is low, and the signal attenuation is large

[0010] In order to solve the above problems, an FFT structure design method with reverse input and sequential output is proposed, which solves the additional storage requirements and pipeline delay problems brought by IFFT. However, GNSS input intermediate frequency signals are input sequentially in the time domain. If this method is used, it must be After windowing processing and before FFT calculation, the input data sequence is processed in "inverted order", so that the data input to FFT is in the order of FFT butterfly operation, and at the same time, the delay M / 2 processing module and windowing processing module are processed in time domain order , however, the "reversal order" processing needs to increase the memory for storage, which consumes a lot of hardware resources

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