A system is described for rapidly and accurately determining the topography of land masses as well as individual x,y,z coordinates of discrete targets. The system incorporates a laser altimeter, a laser scanning/steering system with sensor for receiving reflected laser beams, a global positioning system or other non-ground-based reference means, a video camera, computers, and processing software. The system, mounted to an aircraft, selectively scans or steers a pulsed laser altimeter over a swath or point on earth. A Global Positioning System (GPS) or other non-ground-based reference means records the aircraft's position, altitude, and time of position. Concurrently, a computer system records and time tags the laser's range, scanner angles, and airborne platform's roll, pitch, and heading. The processing software correlates all events and measurements using time to determine precise x,y,z coordinates of the ground/targets. Finally, the system post processes the combined data to produce significant terrain, vegetation, and cultural data.
A system and apparatus for acquiring images of electric transmission line tower structures, equipment attached to said tower structures, and transmission lines suspended from said towers. The system uses a fixed wing aircraft and an arrangement of at least one still camera, means for detecting a tower structure, a data storage unit, and a central processing unit containing operational software. The central processing unit is connected to the camera, the means for detecting a tower structure, and the storage unit. The detection means is a laser altimeter or a combination of preset longitude/latitude coordinates for tower locations and a GPS unit which supplies continuous longitude/latitude coordinates for the aircraft location for comparison to those preset coordinates. The aircraft is flown along the transmission line at a predetermined altitude above the tops of said towers (60 100 feet). The still camera points rearwardly relative to the line of flight of the aircraft and take a picture from between two adjacent towers and along an exposure line directed downwardly at an angle to the line of flight, 30 60 degrees and preferably 45 degrees. The detecting means transmits a signal to the central processing indicative of the presence of a tower to be photographed. The central processing unit calculates the time delay necessary for said aircraft to fly past the tower to a predetermined exposure point located between the tower to be photographed and the next tower in said transmission line after the tower to be photographed. The still camera is activated at the exposure point to acquire an image of the tower structure. The data corresponding to the acquired image is transmitted to a data storage unit for later retrieval and examination to identify defects in the tower or the equipment or transmission lines suspended form the tower. The system is reset to continue acquiring images along the transmission lines. The system is also provided with a video capability to film the towers and transmission lines and the line right-of-way.
A ground-based method is disclosed which determines the spatial statistics of fragmented and spatially variably dispersed objects in a transmissive medium, by generating a plurality of pulsed beams of laser energy, the beams having selectively variable width and shape; selectively varying the width and shape of the beams; directing the beams toward the dispersed objects; measuring the time and/or phase and intensity of signals returned by the dispersed objects, and calculating the apparent reflectance of the dispersed objects as a function of the range of the dispersed objects for each beam width and beam shape.
A scanning arrangement has a device (40) for projecting a two-dimensional optical pattern on a surface (35) of a scanned object. A two-dimensional photodetector (34') is mounted within a hand-held scanning device and outputs scan files of 3D coordinate data of overlapping surface portions of the object. The surface portions defined by these scan files are registered by appropriate rotations and translations in a computer, which are determined either from the outputs of a gyroscope (51) and an accelerometer (50) or by mathematical processing of the surface portions, e.g., involving detecting and location of common features.
This invention concerns a method of making airborne geophysical measurements. Such measurements may be made from fixed or moving wing airplanes or dirigibles. The method comprises the following steps: taking first real time measurements from one, or more, geophysical instruments mounted in an aircraft to produce geophysical data related to the ground below that instrument. Taking second real time measurements from navigation and mapping instruments associated with or carried by the aircraft. Computing a background response of each geophysical instrument using the second real time measurements to take account of its time varying altitude, and the time varying topography of the ground below it. Adjusting an operating or data processing condition of each geophysical instrument using the respective background response and the instrument's attitude to enhance the performance of that instrument. And, adjusting the geophysical data output for that instrument having reduced effects resulting from variations in altitude, attitude and topography.
A scanning arrangement has a device (40) for projecting a two-dimensional optical pattern on a surface (35) of a scanned object. A two-dimensional photodetector (34') is mounted within a hand-held scanning device and outputs scan files of 3D coordinate data of overlapping surface portions of the object. The surface portions defined by these scan files are registered by appropriate rotations and translations in a computer, which are determined either from the outputs of a gyroscope (51) and an accelerometer (50) or by mathematical processing of the surface portions, e.g., involving detecting and location of common features.
