Research And Development Of Measurement Techniques Of Railway Ground Information

Railway ground information system is an important part of train control system. Ground control information includes track circuit information and temporary speed limit information. These control signals need to be measured effectively for the train operation safety.China developed the China Train Control System (CTCS) according to its own situation. Train Operation Control and Monitor Device (LKJ) is a necessary part of CTCSO and CTCS1 systems. Because there are also some shortages in ground information processing in current LKJ system, such as complex structure and low capacity of ground information processing, this thesis proposes some improvements for these shortages.This new design removes the onboard cab signal equipment. The ground information processing board of LKJ is not only used to get the track insulation node signal in the original program, but also used to demodulate the low frequency information. The design could simplify the system structure and the signal processing program with the advantage that the type of the track circuit can be got from the main control board.And for the frequency-shift signal processing, this thesis also proposes an improved real modulation ZFFT (Zoom FFT) algorithm. As the zoom spectrum of the normal ZFFT algorithm is not in accordance with the actual spectrum, real modulation is used to avoid the spectrum rectification. Because the sequence is also real sequence after low-pass filter and decimation, the FFT optimal algorithm for real sequence can be adopted. Compared to the normal algorithm, the improved algorithm could greatly promote the computational efficiency.In addition, the receiving and processing of temporary speed limit information are added to ground information processing system by radio frequency (RF) technology, and the specific solution is presented in this thesis.According to the above improvements, this thesis designs the hardware and software of the ground information processing system based on DSP platform. Finally, testing and validation are carried out. The test results show that this system could achieve the real-time, reliable, efficient demodulation of frequency-shift signal and it could meet the design requirements. And the results lay a good foundation for its practical application in the new LKJ system.