Continuous wave interference detection method in Loran-C timing and positioning terminal

Abstract

The invention provides a continuous wave interference detection method in a Loran-C timing and positioning terminal, which combines a Loran-C signal capture result, selects a silent zone without a Loran-C pulse group position to obtain a frequency spectrum, and reduces the influence of a Loran-C spectral line on continuous wave interference detection. Noise spectrums are suppressed through incoherent accumulation processing, and the sensitivity of continuous wave interference detection is improved; after a continuous wave interference spectral line is suppressed through sliding median filtering, a trend term is eliminated through a curve fitting method, an interference spectral line with a stable noise floor is obtained, and the influence of the trend term on continuous wave interference detection is reduced; and a self-adaptive threshold is adopted, so that the continuous wave interference detection probability is improved.

Description

technical field [0001] The invention belongs to the field of ground-based radio timing and navigation signal processing, and relates to an interference detection method, which is mainly used in Loran-C timing and positioning application terminals. Background technique [0002] The signal of the Global Navigation Satellite System (GNSS) is weak, vulnerable to interference, deception, and occlusion. It is a military target, and there are reliability problems in the guarantee of location and time services in extraordinary times. The Loran-C system has the advantages of high transmission power, strong anti-interference ability, long signal action distance and stable phase. It is a long-range land-based radio positioning, navigation and timing service system. It is internationally recognized that the Loran-C system can be used as a satellite. The ideal complement and backup for the navigation system. my country's existing Loran-C system includes the "Changhe No. 2" navigation sy...

AI Technical Summary

Problems solved by technology

However, there are three problems in the frequency domain detection: (1) The Loran-C signal is bursty in the time domain. During interference detection, the continuous wave interference and the spectrum of the Loran-C signal are aliased, which affects the detection threshold setting and detection performance. ; (2) When the amplitude of continuous wave interference and noise is relatively small, the continuous wave interference spectral line will be submerged in the noise spectrum, resulting in low detection sensitivity; As a result, the low noise of the curve of the spectrum is non-stationary and slowly changing trend items. The trend items will lead to unreasonable detection thresholds and affect the calculation and detection accuracy of detection thresholds.

These three aspects will seriously affect the sensitivity and accuracy of continuous wave interference detection, which in turn will lead to poor suppression of continuous wave interference, and ultimately affect the accuracy and stability of Loran-C timing and positioning results

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