Software defined radio approach to distance measuring equipment

This work describes the methodology used for the development of an avionics system, specifically the distance measuring equipment (DME), from the simulation phase to its implementation in a low cost embedded real time system. The approach considered is based on software defined radio (SDR), that is, all the main functions and signal processing are carried out by an embedded central processing unit (CPU). The purpose of this paper is to show the challenges, such as compatible designing, and advantages of the SDR approach to avionic systems. The laboratory test results show the feasibility of the low cost prototype attaining distance measuring accuracies better than 20 m. Basic minimum operational performance standards are met, while full compliance must be still assessed in order to obtain authorization for the next phase of the project, that is flight testing.