A REVIEW AND ANALYSIS OF THE MCDONNELL DOUGLAS COLLISION AVOIDANCE SYSTEM. PHASE II
Arthur Krinitz · Defense Technical Information Center (DTIC) · 1975
The study represents the second phase of IDA's evaluation of the Collision Avoidance System (CAS) development by the McDonnell Douglas Electronics Company (MDEC). The MDEC CAS is an air-derived synchronous system based on time/frequency multiplexing techniques - synchronization timing is disseminated by ground stations and by air-to-air relay among appropriately equipped aircraft. Range-rate measurement accuracies were re-examined because of the design changes, i.e., replacement of doppler measurements with range difference measurements. Synchronization was addressed in some detail to complement the Phase I study. In particular, the limitations imposed by transmitter power, antenna nulls/fades, and receiver sensitivity were analyzed in the context of the air-to-air synchronization relay links. Ultimately, the analysis led to the question: 'What happens when there is no synchronization and the asynchronous Back-Up Mode (BUM) will have to be invoked'. For this reason, a portion of the study was devoted to the analysis of the BUM.