Remote sensing apparatus and a frequency analysis method of the remote sensing apparatus

• US 7,161,733 B2
• Filed: 03/02/2006
• Issued: 01/09/2007
• Est. Priority Date: 09/09/2004
• Status: Active Grant

• Current Assignee: Kabushiki Kaisha Toshiba (Toshiba Corporation)
• Original Assignee: Kabushiki Kaisha Toshiba (Toshiba Corporation)
• Inventors: Fukata, Shimpei, Narumi, Noboru
• Primary Examiner(s): Lee; John D.
• Application Number:
  US11/365,860
• Publication Number:
  US 20060169932A1
• Time in Patent Office: 313 Days
• Field of Search: 250230-233, 250/236, 250/227.18, 250/227.23, 359326-332
• US Class Current: 359/326
• CPC Class Codes: G01D 5/30 the beams of light being detected by photocells
• CPC Class Codes: G01D 5/3473 Circular or rotary encoders
• CPC Class Codes: G01P 3/36 Devices characterised by the use of optical means, e.g. using infrared, visible, or ultraviolet light G01P3/68 takes precedence; gyrometers using the Sagnac effect, i.e. rotation-induced shifts between counter-rotating electromagnetic beams G01C19/64
• CPC Class Codes: G01P 3/44 for measuring angular speed G01P3/56 takes precedence
• CPC Class Codes: G01P 3/486 delivered by photo-electric detectors
• CPC Class Codes: G01S 17/50 Systems of measurement based on relative movement of target

Abstract

A remote sensing apparatus includes an optical system device, a frequency converter, and a frequency analyzer. The device transmits laser light generated from a laser light source toward an optical pattern rotary plate to receive its reflection light by an optical receiver. The plate is a measurement object. The converter converts a reception signal obtained by the receiver into a signal in a frequency domain. The analyzer analyzes a frequency component of the signal obtained by the converter, selects candidate values of sideband wave frequencies from the signal in the frequency region, obtains an approximate value of a rotational frequency by decision of a majority of intervals of the sideband wave frequencies, obtains candidate values of the carrier frequency from the approximate value, and selects the rotational frequency on the basis of the candidate values of the rotational frequency from among the candidate values of the carrier frequency.

Claims

1. A remote sensing apparatus, comprising:

an optical system device which transmits laser light generated from a laser light source toward an optical pattern rotary plate being a measurement object to receive its reflection light by an optical receiver;

a frequency converter which converts a reception signal obtained by the optical receiver into a signal in a frequency domain; and

a frequency analyzer which analyzes a frequency component of the signal in the frequency domain obtained by the frequency converter, wherein

the frequency analyzer selects candidate values of sideband wave frequencies from the signal in the frequency domain, obtains an approximate value of a rotational frequency by decision of a majority of intervals of the sideband wave frequencies, obtains candidate values of a carrier frequency from the approximate value and selects the rotational frequency on the basis of the candidate values of the rotational frequency from among the candidate values of the carrier frequency.

2. A frequency analysis method of a remote sensing apparatus which transmits laser light toward an optical pattern rotary plate being a measurement object, receives its reflection light from an optical receiver and converts its reception signal obtained by the optical receiver into a signal in the frequency domain to perform a frequency analysis, the method comprising:

selecting candidate values of sideband wave frequencies from the signal converted into one in the frequency domain to obtain an approximate value of a rotational frequency by decision of a majority of intervals of the sideband wave frequencies;

obtaining candidate values of a carrier frequency from selection results of the candidate values of the sideband wave frequencies; and

selecting the rotational frequency on the basis of candidate values of the rotational frequency from among the candidate values of the carrier frequency.