摘要: This is a final report on the first phase of an investigation into new techniques for communicating digital data between aircraft and other terminals. The impetus behind the research is the necessity to develop low-cost, high perf... 展开 This is a final report on the first phase of an investigation into new techniques for communicating digital data between aircraft and other terminals. The impetus behind the research is the necessity to develop low-cost, high performance digital data-links for a variety of aircraft operating in a variety of interference environments. The goal of the investigation is to develop realtime, sampled-data processing techniques to combat both natural and intentional interferences on aeronautical radio navigation and data-link channels. Such processing techniques, if not overly complex, offer the potential for low-cost implementation. In order not to make a Priori assumptions which would force high cost implementation, a processing approach is sought which is relatively independent of signal modulation type. Thus, the thrust is toward signal processors which operate essentially as modems on the output of standardized, unsophisticated radio receivers. A certain amount of the investigative effort concerns mathematical modeling of the multipath perturbations and of possible additive interfering signals. Advantage is taken of prior NASA work in antimultipath reception. In the present effort, the restricted NASA multipath channel model is generalized sufficiently to be realistic for narrow or wideband signal modulations. Next, the detection of digital signals in the postulated channel is considered in the most fundamental framework of probabilistic decision theory. Finally, a Monte Carlo simulation program is designed and tested, for exercising the detection algorithms. 收起