Study On Location Algorithm Of Vehicle Based On RFID And DSP

In the 21st century, Intelligent Transportation System (ITS) has become the inevitable trend of city traffics, which is the key to many traffic problems. Intelligent vehicle location system is the central part of ITS. This paper puts emphasis on location of vehicle, which is a sub-system of new style intelligent vehicle surveillance system proposed by Dr.Mu.A fixed-point time estimation algorithm estimating non-integer TOA is designed based on RFID and DSP. It could get the TOA (Time of Arrival) in real time. The TOA will be used in next step that estimate the vehicle using Chan algorithm. Then this paper analyses the performance of the Chan algorithm to estimate the vehicle location. Then for the big error of estimating TOA, an amend Chan algorithm is presented so that it could perform well. For more precision of the estimation, it presents a Robust location algorithm. The main works of this paper is as follows:(1) How to realize the LMSTDE (Least Mean Square Time Delay Estimation) algorithm in finite word length and make sure the precision is studied.(2) The parabolic-fit interpolation method is introduced to solve the problem that the LMSTDE algorithm only estimates the integer TOA so that it could estimate the floating-TOA in reality. It takes 7060ms using VC++ on the PC(CPU:2.2GHz, Memory Cache: 2G) but only 114.688 milliseconds on the TMS320DM642. It's 60 times as pc.(3) A modified Chan algorithm is presented to improve the location precision in finite word length TOA algorithm having big estimation error.(4) For more location precision, a robust location algorithm is proposed. The experiment result shows that mean error of location of robust location algorithm is 10.1933m, the Chan algorithm is 18.8331m when SNR = -5dB. When the SNR decreases to -25dB the mean error of location of robust location algorithm is 71.2950m and the Chan algorithm is 139.1173m, almost 2 times of robust. It turns out that the robust has a good performance especially in the bad environment.(5) The simulation of location system is performed in the end. The result shows that this paper proposes the robust location algorithm is good enough to realize the location of vehicle in a city area.