The Analysis And Design Of FPGA-based Angle Measurement Module Of Airborne Satellite Antenna

A satellite communication network can be formed by the link between a satellite communication earth station and a geosynchronous orbit communications satellite. With the development of satellite communication technology, both the domestic and international markets make higher request to satellite communication earth station. Airborne satellite communication earth station came into being.During the flight, the aircraft is inclined, which will cause the existence of pitch angle and roll angle. But the "Connection in Moving" airborne antenna needs a relatively stable platform to keep the antenna is always directed at the satellite. Therefore, the airborne system needs an inclination measuring instrument, which is used to measure the pitch angle and roll angle dynamically and send them to the Antenna MCU, so that the MCU can adjust the platform in the real time. This article researchs on the sensor system of airborne antenna. At the base of the analysis of gyroscopes and accelerometers’ characteristics, we fuse the datas from two different sensors by Kalman algorithm, thus the module has excellent dynamic performance.In this design, a FPGA chip from Altera Corporation is used as the module MCU. During the fight, the acceleration can be mesures by a tri-axis accelerometer, and with relevant calculation,we can get the inclination angle. However, this angle is not reliable in a dynamic environment. So, a three-axis gyroscope is necessary as well, thus we get inclination by another method. Kalman filtering algorithm fuses the two datas reasonably. By this way, the module outputs higher precision in a dynamic environment. At last, the module send the data to the Antenna MCU by a serial interface and then the MCU makes a corresponding adjustment to make sure the platform is steady relatively. According to the performance test, this module has a high precision and can be used in the airborne system.