iPCM Telemetry Protocol: Reliability and Bandwidth Improvement for PCM IRIG-106

摘要

A reliable telemetry link is a key element to reduce reflies and to enhance test flight efficiency (i.e., real-time test point validation) and safety in flight test campaigns. However, the telemetry link undergoes losses owing to radio frequency noise and flight test maneuvers. In addition, the telemetry community has been facing a reduction of the available bandwidth owing to electromagnetic spectrum auctions. Many methods have been presented to solve these problems; however, no conclusive solution has been obtained. In view of these issues and by focusing on flight test requirements, IPEV, an Air Force Flight Test Center, proposed an integrated pulse code modulation (iPCM) Telemetry protocol as a potential solution to vital matters regarding the reliability and bandwidth of telemetry links. This paper presents the iPCM architecture and the ground and flight test results. Test results demonstrated the iPCM's capability to recover corrupted data and ensure data integrity and reliability. In a flight test, 100% of the data was successfully retrieved by iPCM without any noise and loss compared with the 98.24% received by PCM IRIG-106. Similarly, for the ground test results, 100% of the data was retrieved successfully by iPCM, and only 88.45% by PCM. In addition, the iPCM protocol provides an option to dynamically select an Flight Test Instrumentation parameter list to be transmitted. In a typical test scenario, this feature of frame changing in the parameter list can achieve a 65% reduction in the bandwidth usage in comparison with PCM IRIG-106.