Kalman filtering based GPS receiver tracking loop

Abstract

The invention discloses a Kalman filtering based GPS receiver tracking loop. One path of carrier signals is correlated with an input intermediate frequency signal to obtain in-phase branch data I; the other path of carrier signals is coupled for 90 degrees and then correlated with the input intermediate frequency signal to obtain orthogonal branch data Q; an advanced signal E, an instant signal P and a lagged signal L are correlated with the I and are also correlated with the Q to obtain in-phase branch accumulation data IE, IP and IL and orthogonal branch accumulation data QE, QP and QL via an integration accumulation module; the IE, IP, IL, QE, QP and QL are connected with the input end of a code ring Kalman filter, and the output end of the code ring Kalman filter is connected with a local C / A code generator; and the IP and QP are connected with the input end of a carrier ring Kaman filter, and the output end of the carrier ring Kaman filter is connected with an NCO carrier wave generator. The GPS receiver tracking loop can track signals whose carrier-to-noise ratio is as low as 19dB-Hz, the tracking error for signals whose carrier-to-noise ratio is 13dB-Hz can be controlled within 10m, and the performance is improved greatly.

Description

technical field [0001] The invention belongs to the technical field of positioning and navigation, in particular to a GPS receiver tracking loop based on Kalman filter. Background technique [0002] In the modern military, long-distance remote control activities such as flight routes, missile trajectories, and combat routes are inseparable from the need for positioning and navigation, especially for long-range drones and intercontinental missiles, which must rely on global satellite positioning. Accurate reach or hit to achieve the target. The signal tracking link of the most comprehensively developed and widely used GPS system receiver under high power noise is the key research object of the present invention. [0003] This is because in some scenarios, the strength of the satellite signal is very weak. For example, when a wireless device works in a dense forest or in a well-enclosed operating room, a typical value of the carrier-to-noise ratio is 25 decibel-hertz (dB-Hz)...

AI Technical Summary

Problems solved by technology

[0006] Under the influence of noise, the receiver cannot accurately judge the C / A code phase, and the code phase error is amplified into a pseudo-range error, which further affects the positioning accuracy. In the process of continuously solving the position, the coordinate value fluctuates greatly; the noise will also make the The phase detector cannot accurately output the local parameter error, resulting in the attenuation of the correlation value between the received signal and the reproduced signal, the stripping of the carrier and C / A code is not complete, and the navigation data cannot be distinguished; or due to the wrong output of the phase detector, the received signal is completely lost. tracking

The positioning accuracy will decrease with the increase of the noise power, so that the identification of the signal is completely lost, and the positioning result cannot be given

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