DEVELOPMENT OF A SERIAL COMMUNICATION PROTOCOL FOR SATELLITE ATTITUDE DETERMINATION AND CONTROL SYSTEM SIMULATOR

Communication

Abstract

The purpose of this research is to design a valid serial communication protocol for satellite and developing Attitude Determination Control System (ADCS) simulator and on Hardware in the Loop (HIL) simulator by using digital signal processing dsPIC30F4013 board. ADCS subsystem consists of actuator, controller, sensor subsystem, and On Board Computer (OBC). These subsystem need to communicate between each other to control and determine the satellite attitude. The ADCS simulator is needed Because of the difficulties of satellite ADCS study in the space.
The development of this simulator is divided into microcontroller (MCU) integration in linear bus, HIL simulator, and analog to digital convertor (ADC). The HIL simulation is done through MATLAB to generate raw data which represents satellite attitude. A PID controller has been used as the control system for the satellite actuator.
ADC feature of the MCU is used to convert potentiometer analog value to digital which represents either satellite temperature or pressure value. Four MCU has been integrated together using RS485 bus with the implementation of token bus access. Cyclic Redundancy Check and checksum had been tested in the transmission.
The entire simulator design program has been done in C language and successful test results show that the research objectives has been achieved with 0.14 as an angle error in degrees with settling time 20s based on simple and low cost hardware with an overall 54.9s for data transfer, therefore these features considered as a contribution regarding too simple, fast and accurate satellite PID controller.