Circuit for rapidly capturing long period pseudo random spread spectrum code of satellite navigation receiver and capturing method thereof

Abstract

The invention discloses a circuit for rapidly capturing a long period pseudo random spread spectrum code of a satellite navigation receiver and a capturing method thereof. The circuit comprises: a data preprocessing module, a sampling data control module, a frequency mixing module, a local spread spectrum code generation module and a single capturing engine. The single capturing engine comprises:a local spread spectrum code memory, a first stage coherent integral module, a first stage coherent data memory, a second stage coherent integral module, a third stage incoherent integral module and a threshold control comparison module. An output terminal of the data preprocessing module is connected with an input terminal of the frequency mixing module through the sampling data control module. The output terminal of the frequency mixing module is connected with one input terminal of the first stage coherent integral module. The local spread spectrum code generation module is connected with another input terminal of the first stage coherent integral module. The circuit of the invention has the following characteristics that: integral gain is high; an anti-electromagnetism interference ability is strong; a capturing sensitivity is high; capturing precision is high; a capturing false alarm rate is low; a capturing speed is fast; reliability is high. And there are many other characteristics.

Description

technical field [0001] The invention relates to a fast acquisition circuit and acquisition method of a long-period pseudo-random spread spectrum code of a satellite navigation receiver. Background technique [0002] At present, the non-geostationary orbit satellite systems that have been built or are under construction in the world include the GPS of the United States, the GLONASS (Global Navigation Satellite System) of Russia, the "Beidou" of China and the Galileo of the European Union. Japan and India have also proposed their own navigation satellite systems. plan. [0003] Satellite navigation and positioning can be achieved through the capture of civilian C / A code and military P(Y) code. The length is very long, and it takes a long time to realize the capture. Generally, the capture of the P code is completed by the guidance of the C / A code. The user first captures the C / A code, and then uses the precise time information provided by the navigation message modulated on ...

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Problems solved by technology

[0005] The purpose of the present invention is to solve the deficiency of existing long-period pseudo-random spread spectrum code capture circuit and method thereof, provide a novel satellite navigation receiver long-period pseudo-random spread spectrum code fast capture circuit and capture method thereof, overcome the traditional The overlap and addition of PN codes in the XFAST algorithm deteriorates the signal-to-noise ratio of the correlation peak at the time of the synchronization code phase, and the capture performance is poor; the direct averaging method and the overlapping averaging method save hardware resources, but the deterioration of the correlation peak signal-to-noise ratio is more serious, so it is necessary to use Compensated by multiple accumulation technology, the average capture time is long; and the traditional capture method has disadvantages such as low integral gain, poor signal-to-noise ratio, poor anti-electromagnetic interference ability, poor capture sensitivity, slow capture speed and poor reliability.

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