A propagation modeling approach to source location and navigation

Abstract

The localisation of interference sources in radio systems is a long standing problem. This topic has been recently seen considerable interest in the context of jammers used to deny GNSS (Global Navigation Satellite Systems) reception on the ground. Such jammers are used (illegally) as privacy protection devices or more seriously to defeat tracking systems in order to commit crime. The growing reliance on GNSS systems such as GPS (Global Positioning System) means that there is also potential for considerably more dire consequences. Critical infrastructure such as telecommunications and electrical power systems can often be reliant upon GNSS for timing. In this paper we present a novel approach to source localisation based on a technique of radio “fingerprinting”. The key objective is to exploit knowledge of the radio propagation environment so as to determine the location of a radio source from as few measurements as possible. At the heart of the technique is the use of a ray-tracing model from which a database is generated containing propagation parameters such as received signal strength and angle of arrival as a function of source and receiver location. These are then used as constraints against which measured data can be inverted to yield the source location. This paper details the planned approach and progress made towards the development of a suitable ray-tracing method and discusses the generation of a database and inversion methods.