Complete self-adaptive notch filter for satellite navigation system and notch filtering method of same

Abstract

The invention discloses a complete self-adaptive notch filter for a satellite navigation system and a notch filtering method of the same, which mainly solve the problems that the existing notch filter can't self-adaptively adjust the notch bandwidth, the notch depth and the notch frequency points of the notch filter under the circumstance that the selective interference characteristics are unknown. The notch filter includes a data collecting and preprocessing module, a self-adaptive notch filtering module and an output control module, wherein the data collecting and preprocessing module converts received intermediate frequency analog signals into baseband digital signals and transmits the baseband digital signals to the self-adaptive notch filtering module, and the self-adaptive notch filtering module notch filters the baseband digital signals by adopting the structure on the basis of the lattice infinite impulse response IIR notch filter, and transmits the notch filtered signals to the output control module for judging and outputting. The complete self-adaptive notch filter can effectively restrain all sorts of selective interference in the satellite navigation system and the selective interference equidirectional with the satellite, and can be used for the anti-interference treatment in the satellite navigation system.

Description

technical field [0001] The invention belongs to the technical field of satellite navigation, and particularly relates to a fully self-adaptive notch filter of a satellite navigation system, which can be used to adaptively suppress various narrow-band interferences in the satellite navigation system, especially the narrow-band interference in the same direction as the satellite, and improve the efficiency of the satellite navigation system. Anti-interference performance. The so-called narrowband means that the interference bandwidth is less than 10% of the signal bandwidth. Background technique [0002] At the end of the 20th century, the navigation system changed from a land-based radio-based system to a space-based satellite navigation system. Satellite navigation and positioning system can provide users with information such as longitude, latitude, altitude, speed and time, and has broad application requirements in military and civilian fields. At present, satellite navi...

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Problems solved by technology

[0004] The traditional notch filter cannot fully adjust the parameters of the notch filter adaptively. For example, both the direct type and the lattice type IIR notch filter need to pre-specify the coefficient α that controls the bandwidth of the notch filter. If the value of α is too large or If it is too small, it will affect the notch effect. In addition, to determine a suitable α, it is necessary to make multiple attempts and adjustments according to the strength and width of the narrowband interference, which is not convenient for engineering implementation.

For the notch filter using the LMS algorithm, a reference input is required, and its frequency is the center frequency of the narrow-band interference that needs to be suppressed. It is difficult to effectively suppress the narrow-band interference when the center frequency of the narrow-band interference is unknown.

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