Travel distance measurement device

Patent metadata

Field	Value
Publication number	US-9500747-B2
Application number	US-201214342981-A
Country	US
Kind code	B2
Filing date	Dec 3, 2012
Priority date	Jan 10, 2012
Publication date	Nov 22, 2016
Grant date	Nov 22, 2016

Abstract

A travel distance measurement device includes a transmitting antenna that is disposed in a vehicle and emits a transmission signal, as a radio wave, toward a ground surface, a receiving antenna that is disposed in the vicinity of the transmitting antenna, and receives a radio wave reflected from the ground surface and acquires a reflection signal, and a distance calculator (an IQ demodulator and a phase conversion integrator) that calculates the travel distance of the vehicle on the basis of the phase of the acquired reflection signal.

First claim

The invention claimed is:

1. A travel distance measurement device comprising:
a transmitter that is disposed in a vehicle and emits a transmission signal, as a radio wave, toward a ground surface;
a receiver that is disposed in a vicinity of said transmitter, and receives a radio wave emitted from said transmitter and reflected from said ground surface and acquires a reflection signal; and
a distance calculator that calculates a travel distance of said vehicle on a basis of a result of integrating a variation of a phase difference between the reflection signal acquired by said receiver and said transmission signal.

2. The travel distance measurement device according to claim 1 , wherein said distance calculator calculates the travel distance of said vehicle by using an angle which is calculated on a basis of emission patterns, heights, and mounting angles of said transmitter and said receiver and at which the reflection signal reflected from the ground surface has a maximum intensity.

3. The travel distance measurement device according to claim 1 , wherein said distance calculator calculates the phase by carrying out orthogonal detection on said reflection signal using said transmission signal, and calculates the travel distance from an integrated phase which said transmitter acquires by integrating a variation of said phase over an interval of 2π or more.

4. The travel distance measurement device according to claim 1 , wherein said transmitter uses a radio wave having a frequency of 24 GHz or more.

5. The travel distance measurement device according to claim 1 , wherein said travel distance measurement device includes: a direction error detector that calculates an angle which a direction of emitting said radio wave forms with a traveling direction of the vehicle; and a correcting operator that corrects the travel distance calculated by said distance calculator by using the angle calculated by said direction error detector.

6. The travel distance measurement device according to claim 5 , wherein said direction error detector measures an acceleration caused by acceleration and deceleration of the vehicle, and calculates said angle on a basis of said measured acceleration.

Assignees

• Inomata Kenji
• Tsujita Wataru
• Tahara Kazuhiro
• Nagashima Seiya
• Mitsubishi Electric Corp

Inventors

• Inomata Kenji
• Tsujita Wataru
• Tahara Kazuhiro
• Nagashima Seiya

Classifications

• G01C21/166

  Mechanical, construction or arrangement details of inertial navigation systems · CPC title

• G01C22/02 Primary

  by conversion into electric waveforms and subsequent integration, e.g. using tachometer generator {(G01C22/002, G01C22/004, G01C22/006 take precedence)} · CPC title

• G01S13/931

  of land vehicles · CPC title

• G01C21/16

  by integrating acceleration or speed, i.e. inertial navigation · CPC title

• G01S13/91

  for traffic control (G01S13/93 takes precedence) · CPC title