Patent ID: 7663536
Filing Date: 2010-02-16
Classification: G01S

Abstract:
1. A ranging apparatus for estimating a distance between a first wireless communication device and second wireless communication device wirelessly communicating with each other, the apparatus comprising: a reference pulse generator generating a reference pulse having a first frequency at a point in time of transmitting a ranging signal from the first wireless communication device to the second wireless communication device; a delay pulse generator generating a delay pulse signal having a second frequency different from the first frequency at a point in time of receiving a response signal transmitted from the second communication device in response to the ranging signal, the first wireless communication device receiving the response signal; an overlap detector detecting a point in time that the reference pulse and the delay pulse overlap each other; a counter counting one of the reference pulse and the delay pulse until the point in time that the reference pulse and the delay pulse overlap each other; and a distance calculator calculating an amount of time from the point in time of transmitting the ranging signal to the point in time of receiving the response signal by applying the first frequency, the second frequency, and a count value of the counter and calculating the distance between the first wireless communication device and the second wireless communication device by using the amount of time.