Yuepeng Yan

A modified histogram bit synchronization algorithm for GNSS receivers

This paper modifies the histogram bit synchronization algorithm. The expressions on probability of both synchronization and false alarm of histogram method have been deduced, and the quantity of measured bits as well as thresholds with best performance is acquired. Compared with results from relational literature, the average time of bit synchronization has almost been shortened by 40%.

Low-Complexity Soft-Decision Decoder Architecture for BCH Code in the BeiDou System

In order to improve the performance of the traditional hard-decision decoding of BCH code in the BeiDou satellite navigation System, a low-complexity soft-decision decoder architecture is designed and implemented in this paper. The designed decoder is based on the syndrome-assisted soft-decision decoding algorithm. A non-uniform quantization scheme and a ROM reduction strategy based on cyclic property are proposed to reduce the hardware resources. Simulation results show that the performance of designed decoder is closed to that of the optimal soft-decision decoding. Compared with the traditional hard-decision decoder, the hardware resource increment is very small, which suggests the designed decoder is a suitable choice in practice.

Analysis and Comparison of Non-coherent and Differential Acquisition Integration Strategies

In the application of global satellite position system, signal adaptive acquisition strategies are required for various environment applications, such as weak signal, emergency moment, so fast and high sensitivity acquisition algorithms are important for the receiver process. This paper presents acquisition algorithms: coherent integration, non-coherent integration, differential coherent and differential non-coherent integration, and the differential integration are analyzed in both standard and pair-wise form, all of which are theoretically compared in their probability distribution with detailed analysis. And testing statics using Monte-Carlo with collected realistic various signal, considering the existence of carrier Doppler frequency and code phase shift in the objectives, give out that in certain probability of detection, differential standard coherent integration is the best detector, non-coherent integration is the second best; and differential pair-wise coherent, differential standard and pair-wise non-coherent integration give out almost the same performance; and the standard algorithm is more tolerable in residual Doppler environment than the pair-wise algorithm; the code phase shift will affect much more in the lower probability of detection; finally, in the theory analysis, the hypothesis of approximated gauss distribution and the IQ data completely independence with each other need to be revised in more accurate model to fit the actual data.

Two modifications of GNSS receiver system in simulation with Matlab

Simulation with Matlab is a basic method in design of GNSS(global navigation satellite system) receiver. Based on the theoretic analysis of spreading code generator and carrier generator in GNSS, this paper proposed modified generators of both code and carrier in Matlab after considering the characteristic of Matlab. Under the condition of different cycles of spreading code and carrier, the modified generating methods had been tested. The results show that, compared with traditional ones, the speed of modified spreading code generator raises by more than 50 times, and the speed of modified carrier generator raises by more than 110 times.

Two modifications in tracking high dynamic GNSS signals using extended kalman filter

This paper proposes two modifications in tracking high dynamic GNSS signals with extended Kalman filter. One is used to estimate the amplitude of signals better, while the other is used to eliminate the phase error of correlator outputs. Simul-ation results show that the variance of estimation and BER of navigation data are both reduced highly.