Directional Wide-Angle Range Finder (DWARF)

The proposed innovation, the Directional Wide-Angle Range Finder (DWARF) is the creation of a laser range-finder with a wide field-of-view (FOV) and a directional measurement component. The technical objective is to create a laser rangefinder with an FOV of approximately 6 degrees and a maximum range of 5 km. The technical objective will be tested by checking the sensor's accuracy and maximum and minimum range measurement capabilities. The Directional Wide-Angle Range Finder (DWARF) is a laser range-finder with a wide field-of-view (FOV) and a directional measurement component. The overall technical objective is to create a laser rangefinder that has an FOV of approximately 6 degrees, a range measurement capability of up to 5 km, and the ability to measure the bearing to the target to within a couple of degrees. The resulting sensor will be tested to determine its range and bearing accuracy as well as maximum and minimum range measurement capabilities. The sensor, if development continues to a flight system, would end up being a maximum of 8 inches long, 4 inches wide, and 4 inches tall (20 x 10 x 10 cm maximum). This approach to directional laser rangefinding is new, but the technical hurdles are small. Each different piece of this work is based on well-known and working technologies. The DWARF approach is innovative because it combines the simplicity of a time-of-flight laser rangefinder with the bearing measurement capability of a quadrant detector and a long-range capability that exceeds most active sensors now available. This effort will result in at least one new technology report. Time-of-flight measurement works by starting a timer when the outgoing pulse is generated and then stopping the timer when the return pulse is detected. Because the speed of light is constant, the measured time directly corresponds to the range to the target. The range resolution depends on the accuracy of the timer – a one nanosecond clock interval corresponds to 15 cm of range resolution. Range = measured-time * speed-of-light/2 The quadrant detector measures the amount of light that hits each quadrant (fourth) of the whole detector. By computing the ratios of the different halves of the quadrant measurements (left / right and top / bottom), the actual bearing to the target can be determined. More »