Simulation of Real-Time Bit Error Rate in Low Earth Orbit (LEO) Satellites Narrow Band and Wide Band Telemetry Radio Link

Abstract

While the Low Earth Orbit satellite has been placed on the determined orbit, ground station has required making a contact with satellite to receive information and control its subsystems. The time variant behavior of the satellite –station radio link should be considered in an appropriate model. This issue has been important because of its high impact on choice the type of the modulation, channel access method designing and error control. In this article the probability of error’s range changes would be estimated momentarily. To achieve this purpose, at first instantaneous communication angles have been measured on the satellite theoretically, and based on these communication angles, the momentary gain in transmitter antennas would be determined. Then, the variation of the signalto-noise rate (SNR) have been achieved momentarily and based on it, Bit error rate (BER) changes would be achieved momentarily, during the time which the LEO satellite has been in the direct view of the telemetry receiver antenna. Channels studied in this paper have been wide-band channels which have been used in transferring images and multimedia messages and these channels have been modeled due to the effects of multipath and shadowing conditions.