Terrestrial network-based positioning and navigation

This chapter presents fundamental positioning techniques typically adopted in most terrestrial networks. A straightforward method of estimating that difference in time is to cross-correlate the signals arriving at a pair of BSs. In order to estimate the angle of arrival (AOA) of incident signals, a directional antenna, such as an adaptive phased array of two or more antenna elements, is required. The straightforward method is to measure the phase difference between the signals, when impinging on different antenna elements, and convert this to an AOA estimate. Conventional methods are based on classical beamforming techniques and do not exploit any assumption on the model of the received signal nor noise. Conventional AOA-estimation techniques electronically steer beams in all possible directions and look for peaks in the output power. Low-cost solutions use lateration, estimating distances from the measured RSS between the MS and the BSs, based on some propagation channel model, usually the log-normal shadow path loss.