Measurement apparatus

Patent metadata

Field	Value
Publication number	US-9753127-B2
Application number	US-201414538205-A
Country	US
Kind code	B2
Filing date	Nov 11, 2014
Priority date	Nov 29, 2013
Publication date	Sep 5, 2017
Grant date	Sep 5, 2017

Abstract

A measurement apparatus measuring a flight time of a search wave corresponding to a time after the search wave is emitted and before a reflected wave is received is provided. The measurement apparatus includes a transceiver, a memory portion, a sampling portion, a measurement portion, and a determination portion. The transceiver emits the search wave and receives the reflected wave. The sampling portion generates a sampling data and causes the memory portion to store the sampling data. The sampling portion includes a first processing unit and a second processing unit. The first processing unit causes the memory portion to store the sampling data as a first signal data. The second processing unit causes the memory portion to store the sampling data as a second signal data. The measurement portion measures the flight time and generates a measurement value of the flight time. The determination portion determines a sampling period.

First claim

What is claimed is:

1. A measurement apparatus measuring a flight time of a search wave corresponding to a time after the search wave is emitted and before a reflected wave of the search wave is received, the measurement apparatus comprising:
a transceiver emitting the search wave, receiving the reflected wave, and outputting a receiving signal;
a memory portion;
a sampling portion generating a sampling data of the receiving signal and causing the memory portion to store the sampling data, wherein the sampling portion includes
a first processing unit causing the memory portion to store the sampling data generated by sampling the receiving signal at a first sampling frequency as a first signal data, and
a second processing unit causing the memory portion to store the sampling data generated by sampling the receiving signal at a second sampling frequency, which is lower than the first sampling frequency, as a second signal data;

a measurement portion measuring the flight time based on the first signal data and the second signal data and generating a measurement value of the flight time; and
a determination portion determining a sampling period of the receiving signal corresponding to the first signal data based on the measurement value of the flight time, wherein
the first processing unit causes the memory portion to selectively store the sampling data of the receiving signal in a specific period with an emission event of the search wave as a reference, as the first signal data, the first processing unit and the second processing unit operating in parallel,
the specific period corresponds to the sampling period determined by the determination portion,
the second processing unit causes the memory portion to store, as the second signal data, the sampling data generated by sampling the receiving signal, the sampling data corresponding to a period longer than the specific period and including the specific period, and
the measurement portion selects, as the measurement value of the flight time, either the flight time calculated based on the first signal data or the flight time calculated based on the second signal data.

2. The measurement apparatus according to claim 1 , wherein
the measurement portion outputs a distance from the measurement apparatus to a front object reflecting the search wave based on the measurement value of the flight time.

3. The measurement apparatus according to claim 1 , wherein
the determination portion determines the sampling period including an estimated time when the transceiver receives the reflected wave, which corresponds to the search wave emitted at a next measurement, based on the measurement value of the flight time.

4. The measurement apparatus according to claim 1 , wherein
the measurement portion selects, as the measurement value of the flight time, the flight time calculated based on the first signal data in response to a determination that the an error between the flight time calculated based on the first signal data and the flight time calculated based on the second signal data is less than a predetermined reference value, and
the measurement portion selects, as the measurement value of the flight time, the flight time calculated based on the second signal data in response to a determination that the error between the flight time calculated based on the first signal data and the flight time calculated based on the second signal data is equal to or greater than a predetermined reference value.

5. The measurement apparatus according to claim 1 , wherein
the measurement portion determines a reliability of the flight time calculated based on the first signal data and determines a reliability of the flight time calculated based on the second signal data, and
the measurement portion selects, as the measurement value of the flight time, one of the flight time calculated based on the first signal data and the flight time calculated based on the second signal data determined to have a greater reliability.

6. A measurement apparatus measuring a flight time of a search wave corresponding to a time after the search wave is emitted and before a reflected wave of the search wave is received, the measurement apparatus comprising:
a transceiver emitting the search wave, receiving the reflected wave, and outputting a receiving signal;
a memory portion;
a sampling portion generating a sampling data of the receiving signal and causing the memory portion to store the sampling data, wherein the sampling portion includes
a first processing unit causing the memory portion to store the sampling data generated by sampling the receiving signal at a first sampling frequency as a first signal data, and
a second processing unit causing the memory portion to store the sampling data generated by sampling the receiving signal at a second sampling frequency, which is lower than the first sampling frequency, as a second signal data;

a measurement portion measuring the flight time based on the first signal data and the second signal data and generating a measurement value of the flight time; and
a determination portion determining a sampling period of the receiving signal corresponding to the first signal data based on the measurement value of the flight time, wherein
the first processing unit causes the memory portion to selectively store the sampling data of the receiving signal in a specific period with an emission event of the search wave as a reference, as the first signal data,
the specific period corresponds to the sampling period determined by the determination portion,
the measurement portion calculates the measurement value of the flight time based on the first signal data and the second signal data, and
the measurement portion selectively refers to the second signal data and calculates the measurement value of the flight time based on the second signal data when a difference between the flight time represented by the first signal data and the flight time represented by the second signal data is equal to or more than a reference value.

7. A measurement apparatus measuring a flight time of a search wave corresponding to a time after the search wave is emitted and before a reflected wave of the search wave is received, the measurement apparatus comprising:
a transceiver emitting the search wave, receiving the reflected wave, and outputting a receiving signal;
a memory portion;
a sampling portion generating a sampling data of the receiving signal and causing the memory portion to store the sampling data, wherein the sampling portion includes
a first processing unit causing the memory portion to store the sampling data generated by sampling the receiving signal at a first sampling frequency as a first signal data, and
a second processing unit causing the memory portion to store the sampling data generated by sampling the receiving signal at a second sampling frequency, which is lower than the first sampling frequency, as a second signal data;

a measurement portion measuring the flight time based on the first signal data and the second signal data and generating a measurement value of the flight time; and
a determination portion determining a sampling period of the receiving signal corresponding to the first signal data based on the measurement value of the flight time, wherein
the first processing unit causes the memory portion to selectively store the sampling data of the receiving signal in a specific period with an emission event of the search wave as a reference, as the first signal data,
the specific period corresponds to the sampling period determined by the determination portion,
the measurement portion calculates a first candidate of the flight time based on the first signal data,
the measurement portion calculate

Assignees

• Denso Corp

Inventors

• Yamamoto Hirofumi
• Taguchi Shinichirou
• Miki Akira

Classifications

• G01S17/10

  using transmission of interrupted, pulse-modulated waves (determination of distance by phase measurements G01S17/32) · CPC title

• G01S17/931

  of land vehicles · CPC title

• G01S17/42

  Simultaneous measurement of distance and other co-ordinates (indirect measurement G01S17/46) · CPC title

• G01S7/4865 Primary

  Time delay measurement, e.g. time-of-flight measurement, time of arrival measurement or determining the exact position of a peak (peak detection in noise, signal conditioning G01S7/487) · CPC title

• G01S17/936

  Physics · mapped topic