In this paper, the bit synchronization algorithms in GNSS receiver are introduced, including the traditional histogram method, K-P algorithm and Viterbi algorithm. The FPGA implementation is also included. A novel tim...In this paper, the bit synchronization algorithms in GNSS receiver are introduced, including the traditional histogram method, K-P algorithm and Viterbi algorithm. The FPGA implementation is also included. A novel time division multiplexing technology （TDM） based on multi-channel shared synchronizer is proposed in this paper to solve the constrained hardware resource problem of multi-system satellite navigation receiver. Through the using of control state machine and data register structure, we realize the multiplexing of bit synchronizer of navigation receiver, which saves the hardware resource. After the experiment, it can be verified that the receiver based on the bit synchronization and multiplexing technology can correctly restore the navigation information.展开更多
SOQPSK是连续相位调制(CPM)中的一类调制方式,具有良好的恒包络特性和频谱利用率高的特点,广泛用于无线测控和无线通信系统当中。由于符号间具有记忆性,解调时需要采用最大似然序列检测(MLSD),对于部分响应的SOQPSK-TG信号,全状态的最...SOQPSK是连续相位调制(CPM)中的一类调制方式,具有良好的恒包络特性和频谱利用率高的特点,广泛用于无线测控和无线通信系统当中。由于符号间具有记忆性,解调时需要采用最大似然序列检测(MLSD),对于部分响应的SOQPSK-TG信号,全状态的最大似然检测复杂度较高。设计了基于脉冲截断的低复杂度相干解调算法,包括MLSD检测以及载波和符号联合同步2个部分。仿真结果表明,该相干解调算法约性能和MLSD检测限相比存在约为0.2 d B损耗,接近MLSD检测限。展开更多
采用微弱信号进行定位是当今研究的一个热点,这一技术的实现基于对弱信号的成功捕获。加长相干积分时间和非相干累加次数是实现微弱信号捕获的基本原理。针对北斗MEO/IGSO卫星因存在NH码二次调制而导致使用GPS捕获方法捕获灵敏度降低的...采用微弱信号进行定位是当今研究的一个热点,这一技术的实现基于对弱信号的成功捕获。加长相干积分时间和非相干累加次数是实现微弱信号捕获的基本原理。针对北斗MEO/IGSO卫星因存在NH码二次调制而导致使用GPS捕获方法捕获灵敏度降低的问题,提出了串行剥离NH码加半比特积分方法。基于FPGA+DSP实现对北斗微弱信号进行捕获的方法,在保证捕获灵敏度的同时,控制捕获时间。测试结果表明,该算法可实现-142 d Bm信噪比条件下的北斗弱信号捕获,并可进一步提高卫星导航接收机灵敏度。展开更多
A velocity determination algorithm of GNSS receiver for high speed and high acceleration carrier in motion is mainly discussed in this paper. For this algorithm, the Doppler frequency value is extracted from the satel...A velocity determination algorithm of GNSS receiver for high speed and high acceleration carrier in motion is mainly discussed in this paper. For this algorithm, the Doppler frequency value is extracted from the satellite carrier tracking loop, and(α, β, γ) filter is adopted for smoothing, and least square is adopted to calculate the receiver speed and local clock drift. To get accurate determination value, a kind of fault detection and exclusion technology(FDE) is designed in this paper; the satellite Doppler frequency value with large error is detected and exclusion. Finally, the signal of GNSS signal simulator and actual navigational satellite signal are received for test, getting good velocity determination result.展开更多
基金the National Natural Science Foundation of China under Grant，the China Postdoctoral Science Foundation under Grant No.2013M530526，the Fundamental Research Funds for the Central Universities under Grant No.FRF-TP-14-046A2
文摘In this paper, the bit synchronization algorithms in GNSS receiver are introduced, including the traditional histogram method, K-P algorithm and Viterbi algorithm. The FPGA implementation is also included. A novel time division multiplexing technology （TDM） based on multi-channel shared synchronizer is proposed in this paper to solve the constrained hardware resource problem of multi-system satellite navigation receiver. Through the using of control state machine and data register structure, we realize the multiplexing of bit synchronizer of navigation receiver, which saves the hardware resource. After the experiment, it can be verified that the receiver based on the bit synchronization and multiplexing technology can correctly restore the navigation information.
文摘SOQPSK是连续相位调制(CPM)中的一类调制方式,具有良好的恒包络特性和频谱利用率高的特点,广泛用于无线测控和无线通信系统当中。由于符号间具有记忆性,解调时需要采用最大似然序列检测(MLSD),对于部分响应的SOQPSK-TG信号,全状态的最大似然检测复杂度较高。设计了基于脉冲截断的低复杂度相干解调算法,包括MLSD检测以及载波和符号联合同步2个部分。仿真结果表明,该相干解调算法约性能和MLSD检测限相比存在约为0.2 d B损耗,接近MLSD检测限。
文摘采用微弱信号进行定位是当今研究的一个热点,这一技术的实现基于对弱信号的成功捕获。加长相干积分时间和非相干累加次数是实现微弱信号捕获的基本原理。针对北斗MEO/IGSO卫星因存在NH码二次调制而导致使用GPS捕获方法捕获灵敏度降低的问题,提出了串行剥离NH码加半比特积分方法。基于FPGA+DSP实现对北斗微弱信号进行捕获的方法,在保证捕获灵敏度的同时,控制捕获时间。测试结果表明,该算法可实现-142 d Bm信噪比条件下的北斗弱信号捕获,并可进一步提高卫星导航接收机灵敏度。
基金supported by the National High-Tech R&D Program (863 Program) No. 2015AA01A705the National Natural Science Foundation of China under Grant No. 61572072+1 种基金the National Science, Technology Major Project No. 2015ZX03001041Fundamental Research Funds for the Central Universities No. FRF-TP-15-027A3
文摘A velocity determination algorithm of GNSS receiver for high speed and high acceleration carrier in motion is mainly discussed in this paper. For this algorithm, the Doppler frequency value is extracted from the satellite carrier tracking loop, and(α, β, γ) filter is adopted for smoothing, and least square is adopted to calculate the receiver speed and local clock drift. To get accurate determination value, a kind of fault detection and exclusion technology(FDE) is designed in this paper; the satellite Doppler frequency value with large error is detected and exclusion. Finally, the signal of GNSS signal simulator and actual navigational satellite signal are received for test, getting good velocity determination result.
