Elshafey

pp.254-269

pp. 328-346

The paper presents main outcome of lossless compression of telemetry information study. Proposed algorithm for lossless telemetry compression is divided in two main steps: decorrelation and entropy coding. We use Normalized Least Mean square (NLMS) adaptive filter as decorrelator and experimented with two different adaptive decorrelation strategies. A comparison of the effectiveness of these different adaptive strategies are performed based on variances and entropy of the resulting prediction errors after decorrelation. In the experiments, data from automatic control system with different parameters are examined, including temperature, pressure and positioning data. These data form a stream of telemetry information conform to IRIG-106 standard. The standard is widely used in the aerospace industry. Different frame structures of that standard (with or without sub-frames) are studied. During the experiments, several algorithms for entropy coding, including Arithmetic, Huffman and Rice codes are also studied as core algorithms at the second step of lossless compression. Comparison of algorithms’ effectiveness and recommendations for development of lossless telemetry compression systems are provided based on acquired results of experiments.

This paper concerns simulation of telemetry information streams transmitted in noise channel. Description of simulator software implementation is provided. The simulator software is designed primarily for R&D aimed to improve properties of telemetry data processing algorithms for frame synchronization data compression end error correction of telemetry data. Introduced telemetry stream simulation technology can be used also in various telemetry processing applications, including testing of telemetry registration systems that support IRIG-06 telemetry frame format, testing and troubleshooting of the software and hardware components of telemetry systems. General interface for creation of telemetry frame structure is introduced. Description of simulated telemetry signals is provided, including test patterns, harmonic signals, arbitrary digital sequences, recorded data, and filtered signals. White Gaussian noise channel model is used to simulate bit errors. This model is applied to individual multiplexer channels of data acquisition system and to telemetry communication channel that is used to transfer stream of telemetry frames.