HIGH-SPEED LASER RANGING SYSTEM INCLUDING A FIBER LASER
First Claim
1. A laser ranging system comprising:
- at least one fiber laser configured to transmit pulses of light to a surface at a rate of at least about 20,000 pulses of light per second, each fiber laser including an optical fiber as an active gain region, wherein the active gain region includes a rare-earth doped element;
laser control circuitry, wherein the laser control circuitry is configured to cause the at least one fiber laser to transmit the pulses of light at the rate of at least about 20,000 pulses of light per second;
an optical receiver configured to receive return signals comprising portions of the transmitted pulses of light reflected from the surface;
elapsed time circuitry configured to measure an elapsed time between transmission of at least one transmitted pulse of light by the fiber laser and reception of at least one corresponding return signal;
a position measurement unit configured to acquire position information corresponding to the position of the laser ranging system;
an inertial measurement unit configured to acquire pitch, roll, and heading information corresponding to movement of the laser ranging system; and
a scanning subassembly configured to direct the pulses of light at various scan angles.
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Accused Products
Abstract
Apparatuses and methods for gathering data describing a surface are disclosed. The apparatuses transmit pulses of light at a high rate using one or more fiber lasers. Examples of such apparatuses include laser ranging systems, such as light detection and ranging (LIDAR) systems, and laser scanners. Data received from the apparatus by a data processing unit can be used to create a data model, such as a point cloud, digital surface model or digital terrain model describing the surface. The surface can be the surface of terrain and/or objects, for example. Use of the fiber laser results in many advantages, such as improved vertical surface discrimination, increased pulse rate, safety benefits, as well as other advantages.
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Citations
39 Claims
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1. A laser ranging system comprising:
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at least one fiber laser configured to transmit pulses of light to a surface at a rate of at least about 20,000 pulses of light per second, each fiber laser including an optical fiber as an active gain region, wherein the active gain region includes a rare-earth doped element; laser control circuitry, wherein the laser control circuitry is configured to cause the at least one fiber laser to transmit the pulses of light at the rate of at least about 20,000 pulses of light per second; an optical receiver configured to receive return signals comprising portions of the transmitted pulses of light reflected from the surface; elapsed time circuitry configured to measure an elapsed time between transmission of at least one transmitted pulse of light by the fiber laser and reception of at least one corresponding return signal; a position measurement unit configured to acquire position information corresponding to the position of the laser ranging system; an inertial measurement unit configured to acquire pitch, roll, and heading information corresponding to movement of the laser ranging system; and a scanning subassembly configured to direct the pulses of light at various scan angles. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21)
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22. A light detection and ranging (LIDAR) system comprising:
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a fiber laser configured to transmit pulses of light to a surface, each pulse of light having a pulse width of about five nanoseconds or less, the fiber laser including an optical fiber as an active gain region; laser control circuitry configured to cause the fiber laser to transmit the pulses of light with a pulse width of five nanoseconds or less; an optical receiver configured to receive return signals reflected from the surface; circuitry configured to distinguish between multiple return signals corresponding to a single transmitted pulse of light; elapsed time circuitry configured to measure an elapsed time between transmission of at least one pulse of light by the fiber laser and reception of at least one respective return signal; circuitry configured to calculate a distance based at least in part on the elapsed time, wherein the distance calculation has a precision of about ten centimeters or less; a position measurement unit configured to acquire information associated with a position of the LIDAR system, wherein the position measurement unit is configured to receive signals from multiple satellites and to calculate positional data from the signals received from the satellites, wherein the positional data includes latitude, longitude, and elevation data; an orientation measurement unit configured to acquire information associated with a pitch, roll, and heading of the LIDAR system, wherein the orientation measurement unit is configured to calculate attitude data of the LIDAR system, the attitude data including heading data, pitch data, and roll data; and a scanning subassembly configured to direct the pulses of light at various scan angles. - View Dependent Claims (23, 24, 25, 26, 27)
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28. A method for acquiring data describing one or more surfaces, the method comprising:
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transmitting pulses of light from at least one fiber laser at a rate of at least 20,000 pulses of light per second, the fiber laser including an optical fiber as an active gain region; for at least one transmitted pulse of light, receiving at least one return signal; for at least one return signal, determining a time of flight of the corresponding pulse of light based at least in part on an elapsed time between the transmission of the pulse of light and reception of the corresponding return signal; calculating distances between a reference and the one or more surfaces; receiving a signal associated with a position of the fiber laser; receiving a signal associated with changes in attitude of the fiber laser; and generating a three-dimensional digital data model using at least the calculated distances between the reference and the one or more surfaces. - View Dependent Claims (29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39)
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Specification