Study Of Software Radio In Tracking And Telemetering Terminal

In both telemetry and telecontrol of space vehicles, it is necessary to track these vehicles and to measure their velocity and range relative to the station. In conjunction with the rapid development of spaceflight cause, the requirement of reliability, general-utility, automatization, miniaturization and supporting multimodel are higher than ever. To meet these requirements are more difficultl by using traditional measuring terminal with only analog and digital circuits, hi this paper, fundamental study is focused on a new measuring terminal which is based on software radio technique.This new measuring terminal, in which the input signal with its frequency 70MHz is sampled directly and the extraction of the target information (velocity, range and angle errors)is performed by the CPLD and DSP techniques, not only overcome essential the difficulties caused by analog devices but also realize many different functions on one hardware platform. Those function can be downloaded from programmable device software and adapted DSP software.In this paper, the principle and the implementation of all the units constructing the new measuring terminal are described extensively; the AID sampler and the down frequency converter and then- performances are studied; the function of internal block models of the CPLD and their implementation are described. Also, the computer simulations of tracking functions of the new terminal are performed using the simulation platform for signal processing worksystem(SPW)and its important specifications are analyzed numerically. The simulation results validate the capability of the new measuring terminal.Finally, we make the conclusion that the new measuring terminal can simplify considerably equipments, enhance their general-utility and flexibility, and significantly decrease their development interval and cost. In practice, this new measuring terminal is of great value to spaceflight task.