Light-backscatter measurement device suitable for use on board a craft
First Claim
1. Light backscatter measurement device, comprising:
- a laser source for emitting short light pulses along a common path;
a channel for receiving a backscattered light flux along said common path, having a detector, andoptical conical scanning means for angularly locating a viewing direction of said device, common to said pulses of light emitted by said laser source and backscattered light returning to said channel, said conical scanning means comprising a mirror, means for rotating said mirror stepwise by successive mutually equal angular intervals about a scanning axis for stopping said mirror in successive angular positions and reflectively diverting said common path to successive diverting paths distributed at said angular intervals and a plurality of stationary reflectors distributed at said angular intervals each on one of said deflected paths, for being successively conjugated with said common optical path by said mirror which has a size much smaller than a size of a beam of said backscattered light flux entering the device from successive viewing directions and reaching said common path and a size of a beam of said light pulses emitted by the laser source and exiting the device.
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Accused Products
Abstract
The device can be used on an aircraft or spacecraft. It comprises a laser for emitting short light pulses, a channel for receiving the backscattered light flux and an optical conical scanner means making it possible to orient a direction common to laser emission and to reception via the channel along successive generatrices of a cone. The scanner has a mirror rotated about a scanning axis for deflecting an optical path common to a receiving detector and to the laser along successive directions distributed at regular angular intervals around the scanning axis and several stationary reflectors distributed at the regular intervals. The reflectors are successively inserted on the common optical path by the rotating mirror. The stationary reflectors correspond to different probing orientations along the cone. The rotating mirror has a size very much less than that of the beam entering and exiting the device.
14 Citations
10 Claims
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1. Light backscatter measurement device, comprising:
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a laser source for emitting short light pulses along a common path; a channel for receiving a backscattered light flux along said common path, having a detector, and optical conical scanning means for angularly locating a viewing direction of said device, common to said pulses of light emitted by said laser source and backscattered light returning to said channel, said conical scanning means comprising a mirror, means for rotating said mirror stepwise by successive mutually equal angular intervals about a scanning axis for stopping said mirror in successive angular positions and reflectively diverting said common path to successive diverting paths distributed at said angular intervals and a plurality of stationary reflectors distributed at said angular intervals each on one of said deflected paths, for being successively conjugated with said common optical path by said mirror which has a size much smaller than a size of a beam of said backscattered light flux entering the device from successive viewing directions and reaching said common path and a size of a beam of said light pulses emitted by the laser source and exiting the device. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9)
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10. A system for use on board a satellite, comprising a plurality of light backscatter measurement devices, each of said device comprising:
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a laser source for emitting short light pulses along a common path; a channel for receiving a backscattered light flux along said common path, having a detector, and optical conical scanning means for angularly locating a viewing direction of said device common to said pulses of light emitted by said laser source and backscattered light returning to said channel, said conical scanning means comprising a mirror, means for rotating said mirror stepwise by successive mutually equal angular intervals about a scanning axis for stopping said mirror in successive angular positions and reflectively diverting said common path to successive diverting paths distributed at said angular intervals and a plurality of stationary reflectors distributed at said angular intervals each on one of said deflected paths, for being successively conjugated with said common optical path by said mirror which has a size much smaller than a size of a beam of said backscattered light flux entering the device from successive viewing directions and reaching said common path and a size of a beam of said light pulses emitted by the laser source and exiting the device, wherein said devices have different orientations so that tracks of their entrance/exit beams on ground exhibit an offset relative arrangement, said devices being used in succession by orienting said common paths of all said devices to switch means operatively associated with said laser source and with said detector via a respective folding mirror and via an additional mirror having the same plurality of angular positions, said additional rotating mirro being driven by a stepper motor.
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Specification