Distance measuring system

• US 7,504,991 B2
• Filed: 03/08/2006
• Issued: 03/17/2009
• Est. Priority Date: 03/11/2005
• Status: Active Grant

• Current Assignee: National Institute of Information and Communications Technology
• Original Assignee: National Institute of Information and Communications Technology
• Inventors: Li, Huan-Bang, Takizawa, Kenichi
• Primary Examiner(s): Tarcza; Thomas H
• Assistant Examiner(s): GALT, CASSI J
• Application Number:
  US11/370,066
• Publication Number:
  US 20060214841A1
• Time in Patent Office: 1,105 Days
• Field of Search: 342/125, 342118-146, 342/42, 342/47, 342/73, 342/85, 342/88, 342/458, 342 70- 72, 342/94, 342 13- 20, 367/47, 367/99, 702/143
• US Class Current: 342/118
• CPC Class Codes: G01S 13/0209 Systems with very large relative bandwidth, i.e. larger than 10 %, e.g. baseband, pulse, carrier-free, ultrawideband
• CPC Class Codes: G01S 13/106 using transmission of pulses having some particular characteristics G01S13/12, G01S13/22, G01S13/24, G01S13/26, G01S13/28 and G01S13/30 take precedence
• CPC Class Codes: G01S 13/76 wherein pulse-type signals are transmitted

Abstract

Disclosed is a distance measuring system comprising a transmitter that sequentially generates pulse sequences each having a plurality of pulse signals of equal amplitudes arranged at equi-time intervals, and transmits the generated pulse sequence as a radio wave; and a receiver that receives the pulse sequence transmitted from the transmitter as a radio wave, and has a distance calculator that acquires propagation times of the pulse signals in the received pulse sequence, and calculates a distance from the transmitter by giving different weightings to the pulse signals for the propagation times acquired for the respective pulse signals. As the amplitudes of the pulse signals in the received pulse sequence become larger, the weightings are made larger.

Claims

1. A distance measuring system:

an Ultra Wide Band (UWB) transmitter including a UWB pulse sequence generator that sequentially generates UWB pulse sequences each having a plurality of UWB pulse signals of equal amplitudes arranged at equi-time intervals, and a transmitting unit that transmits the pulse sequence generated by the pulse sequence generator as a radio wave; and

a UWB receiver including a receiving unit that receives the pulse sequence transmitted from the transmitter as a radio wave, and a distance calculating unit that acquires propagation times of the pulse signals in the pulse sequence received by the receiving unit to reach the receiving unit from the transmitting unit, and calculates a distance from the transmitter based on a propagation time for a selected pulse signal to reach the receiving unit from the transmitting unit,

wherein the distance calculating unit selects said selected pulse signal by acquiring an average value of the amplitudes of the pulse signals in the pulse sequence received by the receiving unit, sequentially calculates an absolute value of the difference between the acquired average value of the amplitudes and the amplitudes of the pulse signals, specifies a pulse signal whose amplitude minimizes the calculated absolute value of differences, and calculates a distance from the transmitter based on a propagation time for the specified pulse signal to reach the receiving unit from the transmitting unit.

2. A distance measuring system comprising:

an Ultra Wide Band (UWB) transmitter including a UWB pulse sequence generator that sequentially generates UWB pulse sequences each having a plurality of UWB pulse signals of equal amplitudes arranged at equi-time intervals, and a transmitting unit that transmits the pulse sequence generated by the pulse sequence generator as a radio wave; and

a UWB receiver including a receiving unit that receives the pulse sequence transmitted from the transmitter as a radio wave, and a distance calculating unit that acquires propagation times of the pulse signals in the pulse sequence received by the receiving unit to reach the receiving unit from the transmitting unit, and calculates a distance from the transmitter by acquiring an average value of absolute values of time differences among the pulse signals in the pulse sequence received by the receiving unit, performing a first estimation to estimate a time of reception of a pulse signal based on the acquired average value and a time of reception of another adjoining pulse signal, and calculating a distance from the transmitter based on the time of reception of the pulse signal estimated in the first estimation and a propagation time for that pulse signal to reach the receiving unit from the transmitting unit.

3. The distance measuring system according to claim 2, wherein the distance calculating unit further acquires an average value of absolute values of time differences among the pulse signals based on the time of reception of the pulse signal estimated in the first estimation, performs a second estimation to estimate a time of reception of a pulse signal based on the acquired average value and an estimated time of reception of another adjoining pulse signal, and calculates a distance from the transmitter based on the time of reception of the pulse signal estimated in the second estimation and a propagation time for that pulse signal to reach the receiving unit from the transmitting unit.

4. The distance measuring system according to claim 2, wherein the distance calculating unit iteratively executes estimation of the time of reception of each pulse signal in said pulse sequence in order to acquire said average value of absolute values of time differences among the pulse signals in the pulse sequence.