JP2016080572A - Laser measurement system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a laser measurement system which is small and lightweight, but is capable of measuring geography highly accurately.SOLUTION: The laser measurement system comprises: a laser range finder 7 including a laser source 11 emitting a laser beam 10, and a diffusion module 15 dividing the laser beam 10 into many laser beams 20 and diffusing them in a quadrangular-pyramid-manner; a frame H holding the laser range finder 7; a GNSS sensor 31 detecting three-dimensional positional information of an aircraft; a gyro sensor G detecting attitude information of the frame H; and a CCD sensor 18 photoelectrically detecting the laser beam reflected by the ground surface.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a laser measurement system, and more particularly to a laser measurement system that acquires topographic information using a laser range finder mounted on an aircraft.

  A laser measuring system that combines a GNSS receiver and an IMU (attitude measurement device) with a laser rangefinder, emits a laser from the aircraft toward the ground, and measures the three-dimensional position of the laser irradiation point (measurement point) is known. It has been.

The laser range finder is configured to measure the distance between the aircraft and the ground surface from the time when the laser was fired and the time when the laser reflected back from the ground surface, and the GNSS receiver is a 3D Configured to measure the target position. On the other hand, the IMU is configured to measure the attitude and acceleration of the aircraft and correct the laser beam emission direction from the measured values. By combining these measurement data, the latitude and longitude elevation of the measurement point can be measured with high accuracy. (Non-patent document 1: Standards and rules of public survey work regulations, pages 326,327, published by Japan Surveying Association).

  Recent laser rangefinders have a laser emission capability of several tens of thousands to 100,000 times per second. By scanning this laser light in the left-right direction with respect to the traveling direction of the aircraft, one flight can be performed. Thus, it is possible to survey a wide band area. When the flight altitude is 2000 m and the scan angle is 20 degrees, the width of the measurement area is about 700 m, and the distance between the measurement points is 50 to 60 cm (refer to HP “Aerial Laser Measurement” of the Geospatial Information Authority of Japan).

  In this way, the conventional scanning method can efficiently measure a wide area, but the number of measurement points is enormous and it takes time to process data, and the scanning mechanism such as a laser reflection mirror is expensive. The problem of lack of durability has been pointed out.

  Therefore, in Patent Document 1 (Japanese Patent Laid-Open No. 2012-225706), a plurality of laser rangefinders are mounted on an aircraft, the angles of the laser emission directions of the laser rangefinders are shifted and fixed, and laser irradiation is performed with these laser rangefinders. Position calculation that calculates the three-dimensional position of the laser irradiation point by combining laser distance measurement means for measuring the distance of the point, distance measurement data obtained from the laser distance measurement means, position information by the GNSS receiver, and attitude information by the IMU And a laser measurement system that reads terrain information on a plurality of lines parallel to the flight line of an aircraft and quickly grasps terrain variations at the time of a disaster.

JP 2012-225706 A Specification

Public Surveys Work Rules Standards Explanation and Operation Pages 326,327 Published by Japan Surveying Association

  However, in such a laser measurement system, since it is necessary to mount a plurality of laser rangefinders on the aircraft, it is large and heavy, and by scanning the laser in the left-right direction with respect to the traveling direction of the aircraft, Compared to conventional laser measurement systems that survey a wide band in a single flight, the accuracy of each measurement point is the same, but the amount of measurement points is small and the amount of information on the ground surface is small. was there.

  Therefore, the present invention is small and lightweight, and surveys the terrain with the same accuracy as a laser scanning system laser measuring system that scans a laser in the left-right direction with respect to the aircraft traveling direction and surveys a wide band area. It is possible to provide a laser measurement system capable of doing this.

  An object of the present invention is a laser measurement system mounted on an aircraft, which detects a laser irradiation device that irradiates a laser beam, a gantry that holds the laser irradiation device, and three-dimensional position information of the aircraft. A GNSS sensor, a posture sensor that detects posture information of the gantry, and a photodetector that photoelectrically detects a laser beam reflected by the ground surface, and the laser irradiation device directs the laser beam to the ground, This is achieved by a laser measurement system characterized by continuous irradiation in a cone shape over a specific time.

  In this specification, an aircraft refers to a vehicle that can fly in the air with a person or an object, whether manned or unmanned.

  In the present specification, the cone includes a cone such as a cone and an elliptical cone, and a pyramid such as a triangular pyramid, a quadrangular pyramid, and an octagonal pyramid.

  According to the present invention, a laser measurement system continuously irradiates a laser beam in a cone shape for a specific time from an aircraft body to the ground, and a laser beam reflected by the ground surface is detected by a photodetector. Therefore, there is no need to provide a scanning mechanism such as a reflecting mirror that scans the ground surface with a laser beam, and therefore the problem of the prior art that the laser measurement system is expensive and not durable is eliminated. Moreover, unlike the laser measurement system proposed by Japanese Patent Laid-Open No. 2012-225706, there is no need to mount a plurality of laser rangefinders. It is possible to solve the problems of the laser measurement system proposed by the specification.

  In a preferred embodiment of the present invention, the laser irradiation device divides the laser beam emitted from the laser light source into a plurality of laser beams, and divides the laser beams into a plurality of laser beams. It is configured to irradiate the ground surface in a cone shape.

  In this specification, dividing into multiple laser beams means an n × n matrix (n is an integer of 2 or more), for example, a 128 × 128 matrix or a 256 × 256 matrix. This means that one laser beam is divided so that the ground surface is irradiated, and the number of many laser beams is not particularly limited.

  According to this preferred embodiment of the present invention, since a large number of laser beams are irradiated in a cone shape from the aircraft body toward the ground surface, the laser beams are reflected by a wide area on the ground surface. It is not necessary to mount a distance measuring device, and surveying can be performed with high accuracy using a small and inexpensive laser irradiation device.

  Further, according to such a preferred embodiment of the present invention, since a large number of laser beams are irradiated in a cone shape from the aircraft body toward the ground surface, it is possible to continuously generate a planar terrain image. It becomes possible.

  In a further preferred embodiment of the present invention, a two-dimensional imaging device is used as a photodetector, and the laser measurement system further detects measurement image data generated by photoelectric detection by the two-dimensional CCD sensor. The posture sensor stores time, the position information detected by the GNSS sensor and the posture information of the gantry detected by the posture sensor, and the image data photoelectrically detected and generated by the two-dimensional CCD sensor. Display means capable of displaying a topographic image based on the corrected image data corrected by the detected attitude information of the gantry is provided.

  According to such a preferred embodiment of the present invention, it is possible to continue the measurement while observing the corrected topographic image in real time.

  In a further preferred embodiment of the present invention, the two-dimensional imaging device is selected from the group consisting of a two-dimensional CCD sensor and a CMOS sensor.

  According to the present invention, it is small and lightweight, and realizes surveying accuracy equivalent to a laser scanning system laser measuring system that scans a laser in the left-right direction with respect to the aircraft traveling direction and surveys a wide band-like region. It is possible to provide a laser measurement system capable of

  In the laser measurement system of the conventional laser scan method, the data that can be acquired at the same time must be one point, according to the present invention, it is possible to acquire data of a plurality of points at the same time, It is possible to provide a laser measurement system capable of realizing more accurate surveying accuracy of an observation target with a severe variation in the time axis.

FIG. 1 is a view showing a horizontal anti-vibration mount on which a laser machine is mounted in a laser measurement system according to a preferred embodiment of the present invention. FIG. 2 is a schematic diagram showing the configuration of the entire laser measurement system according to a preferred embodiment of the present invention. FIG. 3 is a block diagram of the horizontal vibration isolator shown in FIG. FIG. 4 is a schematic perspective view of a laser beam emitting portion of the laser distance measuring device. FIG. 5 is a schematic perspective view of a laser beam receiving unit of the laser distance measuring device. FIG. 6 is a block diagram of the measuring device of the laser measuring system shown in FIGS. FIG. 7 is a flowchart showing processing executed by the controller in this embodiment. FIG. 8 is a schematic longitudinal cross-sectional view of an accident site where a landslide occurred in the case of obtaining a landslide state using the cross-sectional data.

  FIG. 1 is a view showing a horizontal vibration isolator on which a laser machine is mounted in a laser measurement system according to a preferred embodiment of the present invention, and FIG. 2 is an overall view of the laser measurement system according to a preferred embodiment of the present invention. FIG. 3 is a schematic diagram showing the configuration, and FIG. 3 is a block diagram of the horizontal vibration isolator shown in FIG.

  As shown in FIGS. 1 to 3, a gyro sensor G is connected to a horizontal anti-vibration mount H attached to a helicopter (not shown in FIGS. 1 to 3), and the gyro sensor G detects it. Based on the attitude measurement data, the X-axis, Y-axis, and Z-axis servo motors 1, 2, and 3 are feedback-controlled so that the attitude of the horizontal anti-vibration stand H remains horizontal regardless of the helicopter tilt. The

  Although not shown, the horizontal anti-vibration stand H is attached to the helicopter via a spring in order to make it difficult to receive vibration of the helicopter.

  As shown in FIGS. 2 and 3, the servo motors 1, 2 and 3 allow the horizontal anti-vibration mount H to rotate around the three axes of the roll axis, the pitch axis and the yaw axis by only the o angle, p angle and k angle, respectively. It is configured to be rotated.

  2 and 3, reference numeral 4 indicates a control unit that controls the servo motors 1, 2, and 3 and the gyro sensor G, and is indicated by reference numeral 5 in FIG. 3. Is the power supply section. As shown in FIG. 3, the three servo motors 1, 2, and 3 are configured to be controlled by the control unit 4 based on the attitude measurement data detected by the gyro sensor G.

  As shown in FIGS. 1 to 3, the horizontal vibration isolator H is further mounted with an IMU (attitude measurement device) and a laser distance measuring device 7.

  FIG. 4 is a schematic perspective view of the laser beam emitting portion of the laser distance measuring device 7.

  As shown in FIG. 4, the laser distance measuring device 7 includes a laser light source 11 that emits a laser beam 10 in a pulse shape, a collimator lens 12 that converts the laser beam 10 emitted from the laser light source 11 into a parallel beam, The laser beam 10 converted into a parallel beam by the collimator lens 12 is divided into a number of laser beams 20 and is provided with a diffusion module 15 that diffuses into a quadrangular pyramid shape. The laser beam 10 incident on the diffusion module 15 is irradiated toward the ground in an n × n matrix, for example, a 128 × 128 matrix. As the diffusion module 15, for example, a diffusion member used in “3D Flash Lidar” (registered trademark) manufactured and sold by Advanced Scientific Concepts, Inc. is preferably used.

  FIG. 5 is a schematic perspective view of a laser beam receiving unit of the laser distance measuring device 7.

  As shown in FIG. 5, the laser beam 20 divided by the diffusion module 15 and reflected by the ground surface is collected by the condenser lens 16 and is detected photoelectrically by the two-dimensional CCD sensor 18.

  FIG. 6 is a block diagram of the laser measurement system shown in FIGS.

  As shown in FIG. 6, the laser measurement system according to the present embodiment receives a radio wave of a controller 30 that controls the operation of the entire system and a GNSS satellite, and the three-dimensional position of the helicopter, that is, latitude and longitude. A GNSS sensor 31 that detects altitude, a gyro sensor G that detects the attitude of the horizontal anti-vibration mount H, a laser distance measuring device 7 that includes a two-dimensional CCD sensor 18, and a survey generated by the two-dimensional CCD sensor 18. A memory device 35 that records image data together with the three-dimensional position information of the helicopter detected by the GNSS sensor 31 and the posture information of the laser ranging device detected by the IMU (attitude measurement device), and the survey image can be displayed in real time A display device 36 is provided.

  In this embodiment, the controller 30 calculates the ground coordinates of the measurement point. FIG. 7 is a flowchart showing processing executed by the controller 30 in this embodiment.

  First, the distance data measured by the laser distance measuring device 7 from the memory device 35, the attitude data of the horizontal vibration isolator H detected by the gyro sensor G, and the three-dimensional helicopter detected by the GNSS sensor 31. The position data is read out.

  The attitude information of the laser distance measuring device detected by the IMU (attitude measuring apparatus) is subjected to rotation matrix processing and rotation matrix processing, and projection calculation for correcting the distance data measured by the laser distance measuring device 7 is performed. Done and the projected coordinates are determined.

  Coordinate calculation is performed using the projection coordinates thus obtained and the three-dimensional position data of the helicopter detected by the GNSS sensor 31, and the ground coordinates indicating the three-dimensional position of the measurement point are calculated.

  The controller 30 stores the ground coordinates indicating the three-dimensional position of the measurement point thus calculated in a predetermined memory area of the memory device 35. Here, the laser beam 20 is simultaneously irradiated in an n × n matrix, for example, toward a 128 × 128 matrix measurement point, and is reflected almost simultaneously by a 128 × 128 matrix measurement point. Since the laser beam 20 is detected by the two-dimensional CCD sensor 18 and the ground coordinates indicating the three-dimensional position of the measurement point are calculated by the controller 30, the ground coordinates indicating the three-dimensional position of the measurement point are stored in the memory device 35. At the same time, the survey image of the ground surface can be displayed on the display device 36 in real time.

  Furthermore, the controller 30 can create contour lines connecting measurement points having the same height and display them on the map displayed on the display device 36. In this case, the cross-sectional data can be obtained by comparing with the previously created map data. From the obtained cross-sectional data, for example, as shown in FIG. In the case of accumulation, it is possible to grasp the position of the accident site and the height and width of the accumulated sediment M, and to quickly grasp the scale of the landslide. In FIG. 8, A is a helicopter.

  According to this embodiment, the laser distance measuring device 7 divides the laser beam 10 emitted in a pulse form from the laser light source 11 and converted into parallel light by the collimator lens 12 into a large number of laser beams 20, and squares. Since it has a diffusion module 15 that diffuses in the form of a spindle, it is small and lightweight, but it scans the laser in the left-right direction with respect to the traveling direction of the aircraft, and measures a wide belt-like region to measure a wide band area. It is possible to realize surveying accuracy equivalent to.

  The present invention is not limited to the above-described embodiments, and various modifications are possible within the scope of the invention described in the claims, and these are also included in the scope of the present invention. Needless to say.

  For example, in the above embodiment, the laser beam 20 reflected by the 128 × 128 matrix measurement points is configured to be detected photoelectrically by the two-dimensional CCD sensor 18, but the 128 × 128 It is not always necessary to photoelectrically detect the laser beam 20 reflected by the measurement points in the matrix form by the two-dimensional CCD sensor 18, and a 128 × 128 matrix using another two-dimensional image sensor such as a CMOS sensor. The laser beam 20 reflected by the measurement point can be detected photoelectrically.

1, 2, 3 Servo motor 4 Control unit 5 Power supply unit 7 Laser ranging device 10 Laser beam 11 Laser light source 12 Collimator lens 15 Diffusion module 16 Condensing lens 18 Two-dimensional CCD sensor 20 Laser beam 30 Controller 31 GNSS sensor 35 Memory device 36 Display device A Helicopter G Gyro sensor H Horizontal anti-vibration stand M Earth and sand

Claims (4)

  A laser measurement system mounted on an aircraft, comprising: a laser irradiation device that irradiates a laser beam; a gantry that holds the laser irradiation device; a GNSS sensor that detects three-dimensional position information of the aircraft; and A posture sensor for detecting posture information and a photodetector for photoelectrically detecting a laser beam reflected by the ground surface, and the laser irradiation device directs the laser beam to the ground for a certain period of time. Laser measurement system characterized by continuous irradiation in the shape of a laser beam.   The laser irradiation device divides the laser beam emitted from the laser light source into a plurality of laser beams, and irradiates the laser beam onto the ground surface in a cone shape. The laser measurement system according to claim 1, wherein the laser measurement system is configured as described above.   A two-dimensional imaging device is used as a photodetector, and the laser measurement system further detects measurement image data generated by photoelectric detection by the two-dimensional CCD sensor, detection time, and position information detected by the GNSS sensor. And memory means for recording together with posture information detected by the posture sensor, and image data generated by photoelectric detection by the two-dimensional CCD sensor is corrected by posture information detected by the posture sensor. 3. The laser measurement system according to claim 1, further comprising display means capable of displaying a topographic image based on the corrected image data.   4. The laser measurement system according to claim 1, wherein the two-dimensional image sensor is selected from the group consisting of a two-dimensional CCD sensor and a CMOS sensor. 5.

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