基于FPGA的扩频OFDM信号半物理仿真技术研究

Semi-physical simulation research of spread OFDM signal based on FPGA

GNSS(Global Navigation Satellite System)信号体制技术已经取得了较大发展,但仍存在一些固有的技术问题并制约着GNSS信号测距精度的提升,为此,各主要GNSS服务供应商均开展了下一代新型GNSS导航信号体制技术的相关研究。基于GNSS扩频调制的思想,将扩频调制技术与OFDM(orthogonal frequency division multiplexing)调制技术相结合,设计和半物理仿真了一种新型扩频OFDM调制的导航信号。研究了扩频OFDM信号生成机理;利用FPGA(field-programmable gate array)技术对扩频OFDM信号进行了模块化设计;基于Xilinx公司Virtex-7芯片对所设计的扩频OFDM信号进行了半物理仿真实现。仿真结果表明,设计的扩频OFDM信号具备一定的工程可实现性,为后续扩频OFDM信号的工程化实现积累了经验并奠定了技术基础,可应用于扩频OFDM基带信号开发和研制。

The GNSS(Global Navigation Satellite System)signal system technology has made great progress,but there are still some inherent technical problems which restrict the improvement of the GNSS signal ranging accuracy.For this purpose,all major GNSS service providers have carried out related research on new GNSS navigation signal system technologies of next generation.Based on the idea of GNSS spread modulation,combines spread modulation with OFDM(orthogonal frequency division multiplexing)modulation,designs and semi-physically simulates a new type of spread OFDM modulated navigation signal.It studies the generating mechanism of spread OFDM signal,the spread OFDM signal is modularly designed with FPGA technology and is implemented semi-physically simulation based on the Xilinx Virtex?7 chip.The simulation results show that the spread OFDM signal designed has certain engineering feasibility and has accumulated experience and laid a technical foundation for the subsequent realization of the engineering of the spread OFDM signal,which can be applied to the development and research of spread OFDM baseband signal.