Artillery Shell Fired Time Detection System Designed Based On Beidou/GPS Dual-mode

Artillery is a kind of conventional weapons, which needs to be tested many times before use. In the test system of the artillery, fired time detection plays a vital role in the whole measurement system. According to the requirements of the subject, we designed a system including fired time detection module, core controller, Beidou/GPS navigation satellite receiving module, AC/DC signal encoding and decoding in IRIG-B code module, display and key module.The system detects the flame at the time of firing artillery based on photovoltaic effect of silicon photocell, so that we can detect fired time. The detection method is universal and robust. Before testing flame, optical system needs to adapt to the current ambient light. Through adjusting bias voltage of amplifier circuit, we can make the output voltage be OV. When intense flame is detected, the output voltage of detection amplifier circuit jumps instantaneous, which is determined as fired time. In order to obtain high-precision fired time, the system takes Beidou/GPS dual-mode module to provide high-accuracy time. With the joint of domestic Beidou navigation satellite signal receiving mode, the system effectively avoids potential safety hazard caused by authorization issues when using a single GPS satellite navigation. When Beidou/GPS navigation module can not receive satellite signals, the system receives time information via IRIG-B code receiving module and outputs time information through IRIG-B code transmitter module. Core controller is a programmable logic device. We designed pulse detection module, Beidou/GPS time decoding module and IRIG-B code encoding and decoding module.Experimental results show that artillery fired time detection system based on Beidou/GPS dual-mode provides high-accuracy zero time for subsequent multi-parameter detection system. It can also provide a time reference system for cameras that are used to track the cannonball. The precision of Beidou/GPS dual-mode module is 100ns, and the error of DC signal decoded by core controller is less than 100ns, the error of AC signal is less than 5 ms. These results have an important significance in the field of artillery parameters test.