分布式捷联姿态基准中数据采集系统的设计

Design of Data Acquisition System in Distributed Strapdown Attitude Reference System

研究了分布式捷联姿态基准中与各捷联姿态基准的IMU相对应的各数据采集系统(DAS)的设计方法。设计时,对挠性陀螺仪的输出采用以∑-△型ADC为基础的A/D转换的量化方案,对石英挠性加速度计的输出采用I/F转换的量化方案并设计了相应的基于CPLD的高性能多路脉冲信号采集器。由于每个DAS是分布式系统中的一个节点,因此为DAS设计了CAN接口。为便于DAS的开发、软件升级和现场调试等,所设计的DAS具有ISP功能。文中着重讨论了提高∑-△型ADC应用精度的方法及基于CPLD的高性能多路脉冲信号采集器的设计方法。测试表明DAS的模拟输入通道在采样率为100Hz时的转换精度接近18位,DAS的计数输入通道的计数精度与理论值一致,DAS的CAN接口工作正常、可靠。

The design method of data acquisition system corresponding to each IMU ot each strapdown attitude reference in the distributed strapdown attitude reference system（DSARS） is discussed. The system applies A/D conversion for the outputs of DTGs based on the ∑-△ ADC, and adopts I/F conversion for the outputs of accelerometers by using multiplex pulse collectors developed on CPLD. Because each DAS is a node in the distributed system, the CAN bus interface is designed for it. In order for the convenience of development, software upgrade and field debugging, the function of ISP is added to the DAS. The method of increasing the accuracy of ADCs used in systems and the method of design pulse collectors are introduced emphatically. The conclusion can be made from the test work that in a certain sampling frequency of 100 Hz, the DAS conversion precision for analog input is quite possible to be up to 18 bit, the precision of the counting channels are consistent with theory, and the work of CAN bus interface is reliable.