Figure 2.1 shows the hardware components and board layout of the Cricket v2 units.
Cricket uses time-difference-of-arrival between RF and ultrasound to obtain distance estimates. Its radio runs at a frequency of 433 Mhz, with the default transmit power level and antennas providing a range of about 30 meters indoors when there are no obstacles.2.2The maximum ultrasound range is 10.5 meters when the listener and the beacon are facing each other and there are no obstacles between them. Our measurements show that the distance accuracy of the Cricket hardware is on the order of 1 centimeter at a distance of up to 3.5 meters, and 2 centimeters in the rest of the 10.5-meter range.
