Research And Design Of Certain Missile-borne Multi-channel Data Acquisition System

In the flight test of certain aircraft, the acquisition and transmission of182flightparameters such as temperature, acceleration and pressure is a key factor in the experiment.The follow up development of the aircraft is directly related to the accuracy and SRN of thedata acquired.This paper researches and designes a multi-channel data acquisition systembased on the technical index of the missile-bornes.According to the structure of the system and the signal-streaming,the paper introducesthe design and optimization measures of every module of the hardware circuit and softwarelogic in detailed.In the hardware design,the input signals of sensors firstly past through theanalog signal condition circuit to reduce the noise and convert impedance before sent toanalog switch.Under the control of the FPGA,the analog switch outputs the specified channelsignal using time-sharing method,and the signal sampling rate is controlled and the data frameis encoded under switching.The A/D converter digitizes input analog signal.After convertion,the data is uploaded to computer through LVDS data transmission link. The paper deeplydiscusses factors of the operation amplifier lacking the ability to drive capactive loads, theconcatenate mode,the leakage current and distributed capacitance of the analog switch,thelayout and route of the A/D converter and the plate of the PCB,which all can affect the dataacquistion channel and sampling precision,and some improvement measures are proposed.Thereliability of the current loop to transmit control command is demonstrated,too. At last, thetotal measurement error which due to each part of the hardware-circuit’s error is analysised.Inthe design software logic, the data frame structure based on the principle of uniform samplingis designed,and the sequential control of the signal channel-switch based on a ROM addresslookup table is realized.The data acquisition process is optimized to further improve thequality of the data.The LVDS data transmission logic and the high reliability combinedcommand is designed.In the end,using the testing platform,the performance of the data acquisition system isfully tested to verify the system whether meet the requirement.And then,using the computersoftware to calibrate the constant value system error to improve the measurement accuracy of the system.Finally,the test results show that this system achieves task requests.