Performance Comparison of RSS and TOA Indoor Geolocation Based on UWB Measurement of Channel Characteristics

Recently, variety of algorithms using received signal strength (RSS) or time of arrival (TOA) has been examined for precise indoor localization. The performance of the TOA based systems is sensitive to bandwidth and occurrence of undetected direct path (UDP) conditions, which degrade the localization performance significantly. The performance of the RSS based systems is less sensitive to the bandwidth and occurrence of UDP conditions. This paper uses UWB measurements in a repeatable framework representing a typical office building to compare the performance of four different algorithms and analyze the effect of the system bandwidth. Two of the algorithms are assisted with the ray tracing (RT) simulated channel behaviour. These algorithms are the newly introduced RT assisted TOA closest neighbor (RT-TOA-CN) and RT assisted RSS closest neighbor (RT-RSS-CN). The other two algorithms are traditional least square TOA (LS-TOA) and closest neighbor with TOA grid (CN-TOAG), previously introduced in the literature. We show that under certain radio propagation conditions and bandwidth requirements the localization performance of a simple to implement RSS based algorithm can be close to the more sophisticated TOA based technique