基于MEMS谐振式气压传感器的数字高度计研制

Development of digital altimeter based on MEMS resonant air pressure sensor

基于一种高精度MEMS谐振式气压传感器研制了用于辅助导航高度通道定位的数字高度计,利用谐振式压力传感器采集大气静压,并进行气压高度转换。采用复杂可编程逻辑器件(CPLD)+单片机(MCU)的硬件架构,通过等精度数字频率计和16位模/数(A/D)转换器测量气压传感器输出的频率信号和电压信号,并进行温度补偿;然后分析气压高度转换过程中的误差来源,通过对拟合的气压进行IIR数字滤波并且根据实际大气和温度条件进行原理误差补偿,提高了高度输出精度。实验结果表明:数字高度计的气压测量在整个工作温度范围内都具有良好的精度,满行程最大误差小于0.02%FS;实测气压高度转换的误差小于0.8 m,具有良好的工程应用价值。

Based on a high precision MEMS resonant air pressure sensor,a digital altimeter is developed to assist navigation height channel location.The resonant pressure sensor is used to collect atmospheric static pressure and convert atmospheric pressure height.The hardware architecture of complex programmable logic device(CPLD)+MCU is adopted to measure the frequency signal and voltage signal output by the air pressure sensor through the digital frequency meter with equal precision and 16-bit analog to digital(A/D)converter,and the temperature compensation is carried out.Then,the error sources in the process of air pressure height conversion are analyzed,and the precision of height output is improved by IIR digital filtering of the fitted air pressure and principle error compensation according to the actual atmosphere and temperature conditions.Experimental results show that air pressure measurement of digital altimeter has good precision in the whole working temperature range,and the maximum error of full scale is less than 0.02%FS.The error of measured air pressure height conversion is less than 0.8 m,which has good engineering application value.