Tilt-compensated laser rangefinder

A tilt compensated laser ranging device for firing a series of laser pulses at a selected target and measuring target reflections of said laser pulses, said device comprising:

• a laser pulse return detector for detecting reflected laser pulses and providing an electronic signal output corresponding to each detected reflected laser pulse, said laser pulse return detector further having an automatic gain control system that adjusts the gain of the laser pulse return detector, said adjustment based on the amplitude of the previously received laser pulse return detector signal, such that a majority of said laser pulse return detector signals have amplitudes within a predetermined range;
• a vertical tilt sensor for determining the vertical angle to the target and having a vertical angle signal circuitry adapted to produce a vertical angle data signal corresponding to said vertical angle;
• a temperature sensor adapted to produce a temperature data signal corresponding to ambient environmental temperature;
• and
• a microprocessor configured to:
• store vertical tilt sensor system calibration look-up tables;
• store temperature sensor system calibration data look-up tables;
• calculate a time-of-flight range;
• calculate a vertical angle from data comprising vertical angle data, vertical tilt sensor system calibration look-up tables, temperature data and temperature sensor system calibration data;
• and
• calculate a horizontal range from the time-of-flight range and the vertical angle;
• wherein measurement of vertical angle data signals are taken at each of a series of discrete predetermined vertical angles and each measurement value of said vertical angle data signals and each corresponding predetermined vertical angle are stored in lookup tables;
• and
• wherein determination of the vertical angle to the target sequentially making multiple measurements of the data signal corresponding to the vertical angle.

A tilt compensated laser ranging device comprising:

• a vertical tilt sensor system for determining a vertical angle between a reflected laser pulse and a reference horizontal plane, said vertical tilt sensor system comprising:
• a vertical tilt sensor;
• and
• vertical angle signal circuitry adapted to produce a vertical angle data signal corresponding to said vertical angle;
• a digital signal processing circuit comprising circuitry configured to:
• calculate a time-of-flight range;
• calculate a vertical angle;
• and
• calculate a horizontal range from the time-of-flight range and the vertical angle;
• and
• an output signal system adapted to produce a horizontal range output data signal corresponding to the horizontal range to the target.