ABSTRACT
This chapter shows how to compute pedestrian position more precisely by using wireless signals from vehicles. It discusses how to use vehicles, besides global positioning system satellites, as anchors in computing pedestrian position. This helps to improve the fixing rate and solve the outage of positioning, especially in urban canyons that have high buildings on roadsides shielding positioning signals from satellites. The estimation of pedestrian-vehicle distance is a key factor when using vehicles as anchors. A conventional method for distance estimation is to exploit the attenuation property of signal strength, received signal strength indicator. The signal from a vehicle arrives at a pedestrian device as different components via different paths, each with its own propagation delay and signal strength. Channel state information information from off-the-shelf WLAN modules at first was used for indoor positioning, where stationary Wi-Fi access points are used as anchors.
