Design Of Automatic Train Protection System Based On DSP

Now, the signal mode of railway blocks in our country is not unified. There are about three signal modes, AC count, FSK and UM-71(ZPW2000).Because of the different frequency of the three signal modes, the automatic train protection system to each signal mode is different. For the safe working of trains in each signal mode, manual method is used in our country now. This method is not up-to-date, which causes the difficulty of speedup of trains. Automatic train protection (ATP) system devices, which are needed in our country for the construction of high-speed railway, metro and city railway, are used in many countries with developed high-speed railway.We develop this ATP system for the safe working of trains in each signal mode (AC count, FSK, ZPW2000) without man operation. The ATP system supports the input of the three signal modes and the filters in each signal's frequency bound in order to distinguish the three signal modes. By using DSP and PIC MCU, the signals are processed; the carrier and low-frequency signal are analyzed. The ATP system's hardware structure consists of three signal-collecting boards with DSPs. With the output of the three boards as the input of the signal judging board, the signal judging board receives the signal from the signal collecting boards and compares the signals, sets the control signals with the 3 Choose 2 rule.Because of the specialty of the railway circuit, it's hard to control the noise of the signal in bad environment, which need high quality of the hardware filter and demodulation algorithm. These are the two difficulties of the ATP system.The signal collecting board is composed by the DSP TMS320F2812 developed by Ti as the core signal processor and the MCU PIC16F877 developed by Microchip as the coprocessor. The signal collection boards do sampling, quantification and process. The signal judging board is developed with double PIC16F877 CPUs and double software to prevent that one MCU's trouble causes the system breaks up. The signal judging board judges the output of signal collection boards and sets the control information.With the cross correlation demodulation algorithm that has high-speed calculation, high precision, anti-jamming and low hardware requests. After several test, the ATP system is absolutely accordant to the standard.