A system for ultrasonic locating using only time difference of arrival measurements, the system comprising: an ultrasonic receiver including four microphones, three of the microphones disposed on a periphery of a housing, and a fourth centrally-positioned microphone between the other three microphones, the ultrasonic receiver operable to receive an ultrasonic signal from an ultrasonic emitter within an environment; and a controller communicatively coupled to the receiver and operable to: a) establish only time difference of arrival measurements of the ultrasonic signal at each of the four microphones, wherein one of the four microphones is chosen as a reference point; characterized by b) assume an arbitrary flight time for the ultrasonic signal in order to obtain three respective flight distances of the ultrasonic signal for each of the three microphones, c) calculate an intersection point of three spheres defined by three radii equal to the three flight distances, d) calculate a distance from the intersection point to the centrally-positioned microphone, e) subtract a distance from a test distance corresponding to a sum of the arbitrary flight time plus the time difference of arrival measurement for the centrally-positioned microphone to establish a test error, and f) repeat steps b) through e), searching different arbitrary flight times along a straight line through the centrally-positioned microphone and intersection point until the test error is less than an accuracy threshold, indicating an actual location of the emitter, wherein the intersection point corresponds to the respective flight distance as obtained in step b). an ultrasonic receiver including four microphones, three of the microphones disposed on a periphery of a housing, and a fourth centrally-positioned microphone between the other three microphones, the ultrasonic receiver operable to receive an ultrasonic signal from an ultrasonic emitter within an environment; and a controller communicatively coupled to the receiver and operable to: a) establish only time difference of arrival measurements of the ultrasonic signal at each of the four microphones, wherein one of the four microphones is chosen as a reference point; characterized by b) assume an arbitrary flight time for the ultrasonic signal in order to obtain three respective flight distances of the ultrasonic signal for each of the three microphones, c) calculate an intersection point of three spheres defined by three radii equal to the three flight distances, d) calculate a distance from the intersection point to the centrally-positioned microphone, e) subtract a distance from a test distance corresponding to a sum of the arbitrary flight time plus the time difference of arrival measurement for the centrally-positioned microphone to establish a test error, and f) repeat steps b) through e), searching different arbitrary flight times along a straight line through the centrally-positioned microphone and intersection point until the test error is less than an accuracy threshold, indicating an actual location of the emitter, wherein the intersection point corresponds to the respective flight distance as obtained in step b). a) establish only time difference of arrival measurements of the ultrasonic signal at each of the four microphones, wherein one of the four microphones is chosen as a reference point; characterized by b) assume an arbitrary flight time for the ultrasonic signal in order to obtain three respective flight distances of the ultrasonic signal for each of the three microphones, c) calculate an intersection point of three spheres defined by three radii equal to the three flight distances, d) calculate a distance from the intersection point to the centrally-positioned microphone, e) subtract a distance from a test distance corresponding to a sum of the arbitrary flight time plus the time difference of arrival measurement for the centrally-positioned microphone to establish a test error, and f) repeat steps b) through e), searching different arbitrary flight times along a straight line through the centrally-positioned microphone and intersection point until the test error is less than an accuracy threshold, indicating an actual location of the emitter, wherein the intersection point corresponds to the respective flight distance as obtained in step b).