Knowledge-based approach to interference mitigation for EMC of transceivers on unmanned aircraft

This paper discusses the results of exploratory research and development to apply and demonstrate a heuristics, knowledge-based approach for analyzing the electromagnetic compatibility (EMC) of co-located radio frequency (RF) spread spectrum frequency hopping transceivers mounted on an unmanned airborne vehicle (UAV) platform. In particular, an expert system pre-processor is used to set up the initial problem and assure the availability of a valid geometry model which is used to compute geodesic losses in the frequency domain. A knowledge base is constructed to contain essential modeling rules and “scripts” describing the steps involved in a validated, bottoms-up/top-down EMC analysis methodology. Problem reasoning is first performed on the system geometry in the pre-processing stage. An expert system based post-processor is then used to “monitor” the signal environment in the time domain and select the interference rejection scheme(s) appropriate for mitigating the effects of interferers present at a victim receptor port. Various interference rejection schemes are considered based on the interferer type and signal environment characteristics. This is necessary since a single interference rejection scheme cannot realistically be expected to suppress all types of interference that may be present.