Software Techniques for Recovering Noisy Telemetry

Abstract

Software techniques for data quality and useability enhancement are used at two steps in the processing of PCM (Pulse Code Modulation) radio telemetry. The first is a software group synchronization which is used where traditional method has failed. The other is a tool for producing a single best quality data file from diverse receivers. Recovering even small segments of valid information from noisy signals may be of major concert. The importance in many applications is because poor signal power is induced by events of great interest such as failure, detonation or exhaust gas dynamics. The radio receiver and bit synchronizer perform nearly optimally in processing of low signal to noise transmissions. It is found that the group synchronization process can be improved with software algorithm. It is convenient to merge available data from a single test into a single file of best available data. Detected signals are recorded at dispersed tracking stations with varying signal quality over time. Upon achieving the best data from each tracking source the reconstructed data from a collection of all sources is further merged. By using known content to detect bit errors a single file of best quality data is available for analysis. Comparative performance data from use on ICBM telemetry is included. A missile is an example of application where the data recovery is particularly critical at events such as staging and launch.