Emitter localization under multipath propagation using a likelihood function decomposition that is linear in target space

The passive non-cooperative localization and tracking of mobile terminals in urban scenarios, called blind mobile localization (BML), is a highly demanding task which occurs for instance in safety, emergency and security applications with non-subscribed phone user locations. Due to the urban environment and physical propagation effects multiple signals which have traveled along different multipaths are received by the observer station. In this paper it is shown how a decomposed likelihood function can be adapted and used to solve the tracking and localization task. An existing decomposition of the range-bearing likelihood function, which is linear in target space, is applied to BML by using a ray-tracer simulation. Furthermore, the approximation of the decomposed likelihood function is discussed in terms of implementation issues. Finally, a ray-tracing simulation and a simulation of the estimation process are used to numerically compare the proposed likelihood function and an existing assignment based approach, both integrated in an SMC implementation of the intensity filter (iFilter).