A high resolution, integrated data acquisition system for aerospace applications

This work describes the design and development of a data acquisition system based on signal conditioning analog-to-digital converters. The system directly interfaces to the sensors by providing electrical excitation to them and accepting the low-level signals from them as input. The magnitude of excitation signal as well as the major parameters for signal conditioning circuitry such as pre-amplifier gain, input signal offset and anti-alias filter cut-off frequency are digitally controlled thereby rendering the system versatile and reconfigurable. The system provides a high-resolution serial digital output of 12 to 16 bits for measurement channels of low frequency parameters such as pressure, temperature and acceleration for further processing by navigation and guidance system, sequencing system or telemetry system in the aerospace vehicle. The benefits of monolithic integration of signal conditioning and digitization functions by using sigma-delta converters, the system design, the test results interfacing to actual sensors such as pressure transducers and resistance temperature detectors and the salient features of the system along with the potential applications are elaborated herein. The design concepts employed here open up new avenues for integrated digital control of the analog interface and signal conditioning blocks in the sensor data acquisition and actuator command interface of avionics systems such as integrated vehicle health management systems for future space transportation applications.