Distance measurement apparatus
US6657704B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | May 30, 2002 |
| Grant date | Dec 2, 2003 |
| Priority date | — |
| Expiry date | May 30, 2022 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01S13/288
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
A forward electromagnetic wave is generated in accordance with a succession of pseudo random noise code signals. An echo electromagnetic wave caused by reflection of the forward electromagnetic wave at an object is converted into a received signal. Direct-current and low-frequency components are removed from the received signal to generate a filtering-resultant signal. The filtering-resultant signal is compared with a preset decision reference voltage to generate a binary signal. The binary signal is sampled into received data. Calculation is made as to a correlation between the received data and the pseudo random noise code signal. The distance to the object is computed on the basis of the calculated correlation. The pseudo random noise code signal is repetitively generated to produce a succession of the pseudo random noise code signals during a surplus time covering a stabilization time taken by the received signal to stabilize in direct-current voltage level.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.