This disclosure concerns estimating the location of a transmitter using multiple pairs of locator nodes with known locations and measuring time of arrival of a signal received from a transmitter. A processor of a location estimation node first determines time difference of arrival values from time of arrival values measured by each pair of locator nodes. The processor then determines likelihood information for multiple candidate locations of the transmitter and estimates the location of the transmitter from the likelihood information. A processor further determines an initial time of arrival value for the received signal and channel impulse response for a radio channel between the transmitter and receiver. The processor then determines a time correction from the channel impulse response based on a first peak of the channel impulse response and a leading edge of the first value. The processor finally determines an improved time of arrival value of the received signal.