Designof Tme Mi Easuring Istrument Bn Asedon GPS

In recent years,with the continuous increase in the demand for high-tech weapons,weapons testing technology has also made great progress.Chronograph is a necessary instrument for measuring the projectile flight parameter or long-range full-ballistic flight time,and its development gets a lot of attention.with This thesis designs a chronograph based on the Global Position System(GPS)signal to obtain UTC time information to solve the technical problems of the existing time measuring instrument.GPS signal can make multiple timing instruments in different places unified at the same time reference for long time measurement.The main contents of this thesis include:1.Understanding the relevant background of the chronograph,including the introduction of time interval measurement technology,and analysis of the development status of the chronograph,and then according to the measurement principle and technical indicators of the chronograph to the chronograph Complete the overall scheme of chronograph.2.Complete the design of the hardware circuit of the chronograph.The hardware circuit is an integrated circuit with Field Programmable Gate Array(FPGA)as the main control chip.The circuit is divided into regions based on a modular idea.It mainly includes:GPS receiving circuit,second pulse signal and data information from GPS-OEM module,and it is synchronized with the local clock.Input pulse signal isolation circuit,adopting high-speed photo-coupler to receive the input pulse signal,isolate the ground wire and transmit it to the test module circuit;communication and data display circuit to ensure that data can be effectively transmitted and calculate the projectile flight velocity in real time,at last display.Designed the Ethernet circuit,which is convenient for other devices to exchange data.3.Complete the design of timing internal logic based on the designed hardware circuit.The work flow includes:receive the data information from the GPS module,analyze and extract the Universal Time Coordinated(UTC)time;synchronize the received second pulse signal with the local clock;receive the projectile pulse signal,pass the local clock and logic The counter measures the time interval between the two signals;completes the reading of the counter data;calculates the projectile flying speed in combination with the input target distance,and displays it through the display unit.at the same time the data can be transmitted to the computer via Ethernet for data recording and log writing4.Perform on-site debugging and field testing of the designed time measuring instrument.Experiments have verified that the time measuring function meets relevant technical indicators demand.