Design And Realization Of GLONASS Navigation Signal Generator In Complex Environment

With the development of social science and technology, users put forward higher demand toperformance of satellite navigation receiver, so it is an inevitable trend to develop a variety of highperformance navigation receivers to meet the users’ needs. In order to test the static performance anddynamic performance of high-quality satellite navigation receiver, it is necessary to simulate thereal-time satellite signals of GPS, GLONASS, beidou navigation system, etc. GLONASS signalgenerator can provide a reproducible and controllable envrironment to the developing and testing ofsatellite navigation receiver in the new generation, which can support the finalization of themeasurement program. It also has the ability of interference and cheating against hostile navigationreceivers. This paper proposes a design of GLONASS satellite signal generator design based onFPGA technology, which realizes the generating of the GLONASS satellite signal contraposing thecomplex environment, and simulated signal has past the signal test and interference/cheating test ofGLONASS recicer. The main research of this paper is as follows:I. The paper introduces the overall structure and hardware implementations of the GLONASSsatellite navigation signal generator as described, which shows the process of the GLONASSnavigationg signal simulating in this design. It introduces the structure and function of clock mudule,baseband/IF mudule, D/A module, peripheral equipment and RF module in details.II. It analyzes the signal structure and navigation message of GLONASS system, and describesthe frequency range, characteristic and modulation form of GLONASS navigation signal. Based onthe signal analysis in details, the paper deduces the mathematical model of DSSS spread spectrumtechnique and real-time GLONASS signal. It also describes the method of estimating dopplerfrequency in carrier and C/A code initial phase.III. It focus attention on the design of the baseband IF modulation module in a specificintroduction, which mainly describe the analysis and simulation realization of synchronous clock, usbcommunication module, Pseudo-random sequence ranging code generator, NCO of IF carrier and PRcode, base band filter, signal modulation module in the logic design on FPGA chip.IV. At the last, it tests the simulated signal’s correctness and ability of interference and cheatingproduced by this GLONASS navigation signal generator through the spectrum analyzer andcommercial navigation receiver, while analysing the actual working effect of designed GLONASSsatellite navigation signal generator. The test results prove that the signal produced by this GLONASSsatellite navigation signal generator can meet the design requirements of GLONASS system and havethe ability of interference and cheating against GLONASS receivers, which also can prove thecorrectness and practicability of the described GLONASS navigation signal generator in this paper.