Design of Data Acquisition System in Distributed Strapdown Attitude Reference System

The design method of data acquisition system corresponding to each IMU of 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.