TECHNICAL FIELD

The present disclosure relates to vehicle location tracking systems.

BACKGROUND

A variety of different systems for determining a vehicle's location are available. Commonly, a vehicle may use a location derived from a global positioning system (GPS), which relies on the availability of satellites to determine the vehicle's location. However, in some environments, satellites may not be available. For example, in underground or indoor environments, such as underground mining facilities or warehouses, access is not available to satellites in order to use GPS to determine a vehicle's location. As a result, in these types of environments, other vehicle positioning systems are used instead to determine a vehicle's location. A majority of these other vehicle positioning systems are radio-frequency (RF) based positioning systems that use triangulation or other techniques that include receiving multiple RF signals to determine a vehicle's location.

Due to conditions in these underground or indoor environments that cause reflection of RF signals, however, accuracy problems can arise with conventional RF positioning systems. For example, multi-path interference can be caused by RF signals that are reflected by the walls and/or other obstacles in these environments and these reflected RF signals can be detected by a receiver of the RF positioning system. These reflected RF signals can cause accuracy problems because the receiver cannot discriminate between the RF signals received directly from the vehicle and the reflected RF signals, leading to anomalous determination of a vehicle's location.

