Vol-4 Issue-1 2018 IJARIIE-ISSN(O)-2395-4396 7274 www.ijariie.com 205 A REVIEW: IN ORBIT RE- PROGRAMMABILITY OF DIGITAL SUBSYSTEMS OF SATELLITE Miral Patel 1 , Sourabhkumar Jain 2 , Alpesh Dafda 3 1 P.G. Student, VLSI and Signal Processing (EC), VGEC-Chandkheda, Gujarat, India 2 Scientist SE, SAC-ISRO, Ahmedabad, Gujarat, India 3 Asst. Prof., Electronics and Communication Engineering, VGEC-Chandkheda, Gujarat, India ABSTRACT Every Spacecraft/ Satellite has many digital subsystems which are widely used for a various kind of controlling and data processing applications. Field Programmable gate arrays are one of the most common elements of these subsystems considering the last minute programmability. Presently, One Time Programmable (OTP) and SRAM based FPGAs are used in the space programs. SRAM based FPGAs are reprogrammable, however this advantage of re-programmability is not used in the space applications as there is no means exist for re-programmability in space of these FPGA device. It means once the functionality of FPGA is fixed at ground, then it cannot be altered in space. Re-programmability of these devices would be useful to fix the bugs, change the functionalities or addition of the new functionalities in due time course resulting in extension of mission life. Here in this project the concept of the partial re-programmability and full re-programmability of SRAM based FPGA as part of the satellite or space craft would be demonstrated. Here we project the solution to this problem. We are providing the solution by achieving re-programmability with unique protocol. This protocol will be supplied to satellite through tele-commands from the earth-stations. The decoder in the design will debug the information and will supply data to particular location in the memory. Full re- programmability can be achieved by providing whole file through tele-commands. Partial re-programmability can be achieved by providing selected amount of data for particular locations in the memory. This approach will reduce the time. Keyword: - SRAM based FPGAs, Re-programmability, Space applications 1. INTRODUCTION 1.1 Which type of FPGA is to be used? Main two types of FPGAs are used in space missions. One is Antifuse technology based FPGA and other is SRAM based FPGA. In Antifuse technology based FPGAs once the design is fused then it cannot be changed. But in space missions after launching the satellite no change can be done in this type of FPGAs. One advantage of Antifuse technology based FPGA is no radiation can affect its contents in space grated devices. But the main disadvantage is its one time programmability. Unlike Antifuse technology based FPGAs, SRAM based FPGA are multiple time programmable. On power up the data stored in the memory goes serially into FPGA to configure it. So we can say that on power up FPGA is configured through memory. But one disadvantage of SRAM based FPGA compared to Antifuse technology based FPGA is its radiation performance is not that much good. 1.2 Which type of memory is to be used?