Indoor angle of arrival using wide-band frequency diversity with experimental results and EM propagation modeling

In this work we have investigated the problem of angle of arrival (AOA) estimation in the indoor environment. Coherent, multi-path signals must be resolved. The approach is based upon measurement of the AOA using a band of frequencies, approximately 10%-20% of center, and utilizes order statistic filtering to estimate the true angle of arrival from the set of individual AOAs. A plane wave model is assumed for the propagating waves and a random arrangement of scatterers between the source and receiver array is assumed. We have constructed a four-element dipole array and associated receiver-acquisition system to test the approach. The results show good AOA estimates can be obtained in a building that would otherwise yield completely inconsistent estimates using narrowband methods. In addition we have simulated EM (electromagnetic) wave propagation characteristics inside buildings using 3-D computer simulation codes based on ray tracing. The model includes the physical and electrical description of the walls and the patterns of the antennas used. The EM modeling is used for evaluating the base level performance of indoor AOA algorithms.