Apparatus and method for estimating distance using time of arrival

• US 7,663,536 B2
• Filed: 09/05/2007
• Issued: 02/16/2010
• Est. Priority Date: 09/18/2006
• Status: Expired due to Fees

• Current Assignee: Samsung Electro-Mechanics Co., Ltd. (Samsung Group)
• Original Assignee: Samsung Electro-Mechanics Co., Ltd. (Samsung Group)
• Inventors: Lee, Sang Yub, Yang, Wan Cheol, Yang, Chang Soo
• Primary Examiner(s): PIHULIC, DANIEL T
• Application Number:
  US11/850,636
• Publication Number:
  US 20080068255A1
• Time in Patent Office: 895 Days
• Field of Search: 342/125, 342/458, 342/134
• US Class Current: 342/125
• CPC Class Codes: G01S 13/76 wherein pulse-type signals are transmitted

Abstract

A ranging apparatus includes a reference pulse generator generating a reference pulse having a first frequency at a first point in time of transmitting a ranging signal from a first device; a delay pulse generator generating a delay pulse signal having a second frequency at a second point in time of receiving the a response signal transmitted from the second device in response to the ranging signal; an overlap detector detecting a third point in time that the reference and delay pulses overlap each other; a counter counting one of the reference and delay pulses until the third point; and a distance calculator calculating an amount of time from the first point to the second point by applying the first and second frequencies, and a count value of the counter and calculating the distance between the first device and the second device by using the amount of time.

Claims

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.

2. The apparatus of claim 1, wherein the distance calculator calculates the amount of time from the point in time of transmitting the ranging signal to the point in time of receiving the response signal by using Equation 2

$\begin{array}{c}T\end{array}$

⁢

x = N ·



1 f ⁢

⁢

0 - 1 f ⁢

⁢

1 

+ δ

Equation ⁢

⁢

2

where Tx indicates the amount of time from the point in time of transmitting the ranging signal to the point in time of receiving the response signal, N indicates one of a count value of the reference pulse and a count value of the delay pulse, f0 indicates a frequency of the reference pulse, f1 indicates a frequency of the delay pulse, and δ

indicates an offset value.

3. A ranging method of estimating a distance between a first wireless communication device and a second wireless communication device wireless communicating with each other, the method comprising:

generating a reference pulse having a first frequency simultaneously with transmitting a ranging signal from the first wireless communication device to the second wireless communication device;

generating a delay pulse having a second frequency different from the first frequency simultaneously with receiving a response signal transmitted from the second wireless communication device in response to the ranging signal, the first wireless communication device receiving the response signal;

detecting a point in time that the reference pulse and the delay pulse overlap each other;

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

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.

4. The apparatus of claim 3, wherein the calculating the distance comprises calculating the amount of time from the point in time of transmitting the ranging signal to the point in time of receiving the response signal by using Equation 2

$\begin{array}{c}T\end{array}$

⁢

x = N ·



1 f ⁢

⁢

0 - 1 f ⁢

⁢

1 

+ δ

Equation ⁢

⁢

2

where Tx indicates the amount of time from the point in time of transmitting the ranging signal to the point in time of receiving the response signal, N indicates one of a count value of the reference pulse and a count value of the delay pulse, f0 indicates a frequency of the reference pulse, f1 indicates a frequency of the delay pulse, and δ

indicates an offset value.