A method for avoiding and stripping neumann‑hoffman codes in d1 navigation messages of Beidou navigation satellite system
A satellite system and navigation message technology, which is applied in the field of satellite navigation to achieve the effect of reducing technical difficulty, simplicity, and improving success rate and accuracy
Inactive Publication Date: 2017-01-25
NANJING UNIV OF AERONAUTICS & ASTRONAUTICS
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Problems solved by technology
[0005] The technical problem to be solved by the present invention is to reduce the computational complexity of the Beidou signal capture by NH code phase calculation, and propose a unique sequence-based capture method, which can successfully avoid the interference of NH code hopping on capture, and at the same time The sub-frame synchronization link realizes the stripping of the NH code, and the present invention is applicable to the process of Beidou navigation receiver signal capture and NH code stripping
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[0028] The technical solution of the invention will be described in detail below in conjunction with the accompanying drawings.
[0029] Please refer to figure 2 As shown, the present invention is directed at the Neumann-Hoffman code avoidance and stripping method in the Beidou navigation satellite system D1 navigation message, and the specific implementation steps are as follows:
[0030] The first step: collect, down-convert and quantize the Beidou satellite signal, and select a continuous signal sequence not shorter than 6 milliseconds to enter the satellite acquisition link;
[0031] Step 2: Generate the local Beidou spread spectrum code and perform 1ms sampling, the sampling frequency is consistent with the satellite signal sampling frequency;
[0032] Step 3: Generate a local carrier with a search step size of 500Hz within the frequency range of the intermediate frequency signal ±10Hz, generate in-phase and quadrature signals, and perform 1ms sampling. The sampling fre...
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The invention discloses an avoiding and stripping method for Neumann-Hoffman codes in navigation messages of a Beidou navigation satellite system D1. The method comprises the steps that according to the encoding characteristics of the Neumann-Hoffman (NH) codes in a navigation message signal system of the Beidou navigation system D1, a unique sequence NH code avoiding method based on probability statistics is proposed at the satellite capturing stage, and the influence of jumping of the NH codes on capturing is successfully avoided; through parallel code phase search with the step length decreasing step by step, accurate capturing of the phase position and carrier frequency of spreading codes of a Beidou satellite is successfully achieved; meanwhile, an NH code stripping method for combined codes based on the NH codes and frame synchronization codes (Pre) is proposed in the frame synchronization step, and stripping of the NH codes and output of the navigation messages can be effectively achieved while subframes are synchronized. The avoiding and stripping method for the NH codes in the navigation messages of the Beidou navigation satellite system D1 is applicable to a Beidou satellite navigation receiver and a software receiver, and the same idea is applicable to other navigation satellite systems for which fixed sequence secondary encoding is adopted.
Description
Technical field: [0001] The invention relates to a method for avoiding and stripping Neumann-Hoffman codes in a D1 navigation message of a Beidou navigation satellite system, which belongs to the technical field of satellite navigation. Background technique: [0002] The secondary coding of the satellite signal system has been widely used in the modernization of global navigation systems such as Beidou and Galileo, as well as GPS. The secondary encoding improves the correlation by prolonging the overall period of the spreading code, which can enable the receiver to quickly realize data synchronization, reduce the interval of spectral lines, and further suppress narrow-band interference. In GPS modernization, the secondary encoding length of L1C signal is 1800, the period is 18s, and the code rate is 100bps. The data channel and pilot channel of L5C signal adopt two secondary encoding lengths of NH code with lengths of 10 and 20 respectively. The Galileo system uses secondar...
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IPC IPC(8): G01S19/30G01S19/24
CPCG01S19/30
Inventor 孟骞曾庆化刘建业冯绍军李荣冰范胜林顾姗姗王焕浩
Owner NANJING UNIV OF AERONAUTICS & ASTRONAUTICS