Intermediate frequency direct sequence spread spectrum receiver for satellite ranging

Abstract

The invention relates to an intermediate frequency direct sequence spread spectrum receiver for satellite ranging, which consists of 37 parts of a front-end A / D, an FFT module, a local PN code generator, a correlator, an automatic threshold calculation module and the like. The connection relationship is as follows: the output of the front-end A / D and the output of a carrier tracking loop NCO are respectively connected to an in-phase branch multiplier and an orthogonal branch multiplier, the input of the front-end A / D and the input of the carrier tracking loop NCO enter into an in-phase branch FIR low-pass filter and an orthogonal branch FIR low-pass filter, consequently, on the one hand, the output is sent to an integral zero clearing device, then the output which is sent to the FFT module, a branch 1 local PN code memory ROM and a branch 2 local PN code memory ROM enters into a branch 1 complex multiplier and a branch 2 complex multiplier, the output is sent to a branch 1 root mean square module and a branch 2 root mean square module, the output is sent to the threshold calculation module and a capturing and judging module for carrying out code catching; and on the other hand, the output is sent to the correlator and the local PN code generator for carrying out code tracking. The output of the correlator is simultaneously sent into a frequency discriminator / phase discriminator of the carrier tracking loop and then enters into a loop filter of the carrier tracking loop, and the output of the loop filter of the carrier tracking loop enters into the carrier tracking loop NCO for carrying out carrier tracking.

Description

(1) Technical field [0001] The invention relates to a spread-spectrum receiver, in particular to an intermediate frequency direct-sequence spread-spectrum receiver for satellite ranging, which belongs to the technical field of satellite communication. (2) Background technology [0002] With the development of aerospace technology, my country's deep space exploration strategy has been officially launched, and preliminary results have been achieved. In October 2007, the Chang'e-1 lunar exploration satellite was successfully launched and sent back a large amount of lunar telemetry data. Space, the use of space has taken the first step. At the same time, the success of lunar exploration will lay a technical foundation for our country to carry out deep space exploration. [0003] In the process of deep space exploration, it is of great significance to know the precise position of the satellite at all times. The positioning of the satellite can not only enable the ground station to...

AI Technical Summary

Problems solved by technology

In order to improve the ranging accuracy and increase the maximum measurement distance, it is necessary to increase the chip rate of the spreading code and choose a longer spreading code, but the higher the chip rate, the higher the hardware requirements and the more difficult it is to realize , the longer the spreading code period is, the more difficult it is to capture and the longer the capture time. Therefore, it is of great significance to design a spread spectrum receiver that can quickly capture long codes with high chip rates

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