TDOA geolocation Time Difference on Arrival (TDOA) uses the difference in arrival times at receivers to geolocate a transmission using a minimum of three receivers. TDOA works particularly well for pulsed transmissions and can resolve multipath effects; it can be combined with AOA and POA using our Multi Geolocation feature. TDOA is a well-proven technique that uses synchronous time domain captures to determine the relative time of arrival of a signal at different receiver locations. The technique is optimal for geolocation over wide areas. Two monitoring receiver points will provide geolocation probability in two dimensions (i.e. approximately along a hyperbolic curve), whereas three or more monitoring receiver points will provide geolocation probability to a bounded area or point. TDOA works best for wider modulation bandwidths with better signal correlation properties and therefore localisation to a narrower area. A significant advantage of TDOA is that the processing gain of correlations allows successful geolocation of signals which are close to, or even below the receiver noise floor. Timing synchronisation is required between the receivers for TDOA. For wide area deployments, this is provided most practically by the RFeye on-board GPS receiver. Using RFeye Arrays, TDOA geolocation results are combined with AOA results to provide unrivalled geolocation performance.