LOW COST, SYSTEMATIC SOFTWARE AND HARDWARE PROCESSES INCLUDING ON BOARD COMPUTER IN LOOP SIMULATION AND HARDWARE IN LOOP SIMULATIONS FOR 'PRATHAM' STUDENT SATELLITE, IIT BOMBAY

摘要

Students from the Indian Institute of Technology Bombay (IITB) are currently in the process of building a plug and play micro-satellite bus "Pratham" in collaboration with the Indian Space Research Organization. There are two main electronic boards on Pratham viz. On Board Computing board which hosts the core controller of the satellite, and the Power Board which distributes power to different loads on the satellite. The requirement imposed by ISRO on the success rate of electronic circuit boards in student satellite is 99%. The testing procedures are categorized as hardware testing and software testing. The paper will discuss the standard procedures followed mainly in Hardware testing of the aforementioned Electronic Circuit Boards involved in the making of Pratham. Step by step process for the hardware testing is used. The software testing is done by real time 'On-board In Loop Simulation (OILS)' where atmospheric and gravity conditions are simulated using standard environment models while GPS, magnetometer and magnetorquer are simulated by hardware interfaces that are mimicked exactly. This will test and validate the hardware interfaces and software accuracy. Sensors and actuators are simulated using Hardware In Loop Simulation (HILS). There are various sensors viz. GPS, Magnetometer and Sun-sensor which give input to the OBC board which then calculates the control inputs required to achieve the desired attitude. The setup used in testing these sensors/ actuators along with OBC board and their results are also included. The testing procedures in both the circuit boards are broken down into various levels with level 0 as fabrication and soldering precautions set by ISRO while final level as integrated testing of entire circuit board. A generalized and systematic troubleshooting procedure for Electronic Circuit Boards is included as well.