Animal Location Tracker (ALT)

The Animal Location Tracker (ALT) is a coil array telemetry receiver. It takes the form of a rectangular platform upon which we can place an animal cage. The coil array is beneath the platform. The ALT uses these coils to decode telemetry signals and also to measure the strength of the radio-frequency signal at each coil. Because the strength of the received signal decreases with range, the is able to use these power measurements to provide a crude estimate of animal location. The Neurotracker calculates the centroid of received power and uses this position as its measurement of transmitter location. In practice, the power centroid distorts animal movements: as an animal moves steadily across the platform, it's apparant position surges forward, veers to the side, and pauses. Neverheless, the power centroid provides us with a robust measurement of activity, direction, and proximity. By activity we mean the distance moved by the animal in a given time, perhaps centimeters per minute. By direction we mean the direction in which the animal moves. By proximity we mean the average separation of animals in the cage. By means of activity, direction, and proximity, we can tell when an animal is asleep, when it is active, whether it is rotating clockwise or anti-clockwise, and whether or not it socializes with the other animals. If we have video tracking of several identical-looking animals in a cage, we can use the ALT's direction measurement to determine which animal contains which transmitter, thus allowing us to identify each animal in view.