Design and implementation of S-band Multi-mission satellite positioning data simulator for IRS satellites

摘要

The Indian Remote Sensing (IRS) ground station operates in both X-Band and S-Band frequencies. The video data is transmitted from the IRS series satellite in X-Band. Also, the telemetry, tracking, telecomm and, acquisition and housekeeping data of satellite is transmitted in S-band. The position of IRS satellite was derived by Interferometry and ranging techniques. These techniques gave the position of satellite at a specified given time and also the positional values derived were less accurate. Hence, there was a need of data which could give more positional accuracy. These accurate values were included in the SPS data, which are currently transmitted in S-band from the IRS series satellites with Global Positioning System (GPS) receivers on board. From this SPS data, satellite imagery products, standard products etc, can be generated more accurately for various applications such as agriculture, forestry, etc. The SPS data is transmitted only for 2minutes approximately during the real-time pass of the satellite. In the absence of this data, it is necessary for the S-band SPS chain to be validated for any kind of malfunctioning of the S-band receive chain systems and subsystems, just before the actual pass of the IRS satellite. The Sband receive chain consists of Phase Demodulator, BPSK demodulator, etc. During the real-time pass of the satellite, it is necessary that the SPS chain should function appropriately for acquiring the SPS data transmitted from the satellite. Hence, to assess the required performance of receive chain in the absence of satellite signal; a specially designed simulator is essential. The proposed simulator is designed and developed specifically to match the onboard signal spectrum of all IRS Series of Satellites. This paper discusses about the design and implementation of different SPS data formats (Multi-mission) Simulator for checking the SPS data chain. This system is found to be validating and evaluating the entire SPS data receive chain.