Abstract: An apparatus and method for measuring coefficients of retroreflectance of retroreflective surfaces such as road signs involves use of a modified light based range finder. The apparatus includes a power attenuation factor data base which relates pulse width of received pulses to power attenuation of the transmitted pulses. The range finder calculates target range based on time of flight of light pulses. The apparatus automatically calculates the absolute coefficient of retroreflectance for an unknown reflective surface being measured by comparison of the measurement to a reading with the same instrument of a known reflectance standard.

Abstract: A tilt compensation method, circuit and apparatus utilizes a two axis tilt sensor or two single axis tilt sensors for alerting, a user and/or compensating a surveying instrument for off vertical alignment above a reference point when the instrument support is free to move about the reference point, e.g., when mounted on a monopod support. The sensor comprises a cell having a central electrode and four peripheral electrodes spaced 90 degrees apart around the central electrode. Fluid in the cell chamber changes the conductance of the electrodes with reference to the central electrode. The cell is mounted to the support or to the instrument itself. A microprocessor preferably provides a square wave drive signal selectively to alternate pairs of the opposing electrodes through tristate buffers while at the same time the microprocessor provides a channel select signal to the gate of the tristate buffers to float the idle electrodes.

Abstract: A laser rangefinder bow sight adapted for use preferably with a conventional multi-pin bow sight having a frame and a plurality of sighting pins adjustably positioned on said frame. The laser rangefinder has a housing removably fastened to the bow sight frame. The housing supports a laser transmit section, a laser receive section, a precision timing section and a central processing unit (CPU) for measuring distance to a target coupled to an LCD display. The CPU also provides outputs to a plurality of range window indicator lights which are preferably LEDs. The indicator lights may be externally mounted to the bow sight pins or mounted within the rangefinder housing. In the latter case, a plurality of optical fibers are connected to the distance window lights in the housing. Each of the sighting pins is optically coupled to a separate one of the plurality of distance window lights via one of the optical fibers.

Abstract: An apparatus and method for accurately determining a target distance in adverse weather conditions utilizing both LASER and RADAR is disclosed. The radar signals are used to determine an approximate range which is then used as a gating window for the determination of which laser reflection is from the actual target as opposed to a reflection from the atmospheric interference. The method basically comprises the steps of initiating a radar pulse in the direction of a target and receiving a reflection, transmitting a laser signal and receiving a plurality of reflections, determining an approximate range based on the radar signals, and using this approximate range to ascertain which of the laser reflections is from the target. This determination is preferably made by generating a gating signal and gate width from the radar signals and passing the set of laser range signals through the gate to eliminate the false signals and select the signal that survives the gate as the accurate target range.

Abstract: A sensor for determining the position of a movable object along a selected axis. The system includes a target positioned at a location aligned with the selected axis. An optical energy emitter is mounted on the movable object and has a beam dispersion greater than two degrees directed at the target. An optical energy receiver is mounted on the movable object and aligned to receive optical energy reflected by the target. The optical energy detector generates a receive signal indicating reception of the optical energy. A time of flight circuit coupled to the emitter and receiver generates a flight time signal indicating the elapsed time from emission of the optical energy to reception of reflected optical energy. A control circuit monitors the flight time signal and outputs a position signal indicating position of the movable object with respect to the target.

Abstract: A highly precise range measurement instrument is made possible through the use of a novel and efficient precision timing circuit which makes use of the instrument's internal central processing unit crystal oscillator. A multi-point calibration function includes the determination of a "zero" value and a "cal" value through the addition of a known calibrated pulse width thereby providing the origin and scale for determining distance with the constant linear discharge of capacitor.

Abstract: An apparatus and method for measuring coefficients of retroreflectance of retroreflective surfaces such as road signs involves use of a modified light based range finder. The apparatus includes a power attenuation factor data base which relates pulse width of received pulses to power attenuation of the transmitted pulses. The range finder calculates target range based on time of flight of light pulses. The apparatus automatically calculates the absolute coefficient of retroreflectance for an unknown reflective surface being measured by comparison of the measurement to a reading with the same instrument of a known reflectance standard.

Abstract: A circuit and apparatus for generating a light pulse from an inexpensive light-emitting diode (LED) for an accurate distance measurement and ranging instrument comprises an LED and a firing circuit. An optional pre-biasing circuit provides a reverse-bias signal to the LED to ensure the LED does not begin to emit light before a firing circuit can provide a sufficiently high current pulse of short duration as a forward current through the LED. The LED is driven by the firing circuit with a pulse of high peak power and short duration. The resulting light pulse from the LED can be inexpensively used to derive distance and ranging information for use in a distance measurement and ranging device.

Abstract: A modular laser-based surveying system is disclosed which comprises a laser-based distance measuring module and a separable compass module removably coupled to the laser based distance measuring module. Each of these modules may be operated as stand alone units as each has its own power supply and display. The system further may comprise a separate angle encoder module adapted to be coupled to either the laser distance measuring module or the compass module and a data logger or computer for processing data transmitted from any or all of the modules.

Abstract: A system for automatically capturing an image of a moving vehicle and recording data parameters, such as date, time, speed operator, location, etc. on the image. A capture window that comprises a predetermined range of distances of the system from the moving vehicle can be set by the operator so that the image of the moving vehicle is automatically captured when it enters the capture window. The capture window distance can be entered manually through a keyboard or automatically using the laser speed gun. Automatic focusing is provided using distance information from the laser speed gun. A database is included to allow the user to search for specified parameters. Data records can be flagged for issuance of citations. A separate office unit is disclosed for retrieving and sorting data records so that field units are not occupied with such tasks. The office unit can be separately connected to licensing databases to retrieve information for issuance of citations.

Abstract: A light-weight, hand-held range finding apparatus of the present invention includes signal emitting circuitry and lens for emitting signals, and signal receiving circuitry and lens for receiving reflected signals, which are positioned within a chamber of a housing. The housing includes an upper section to which a sighting device is attached, a front end through which the emitted signals are emitted and the reflected signals are received, a back panel having a display device attached to said housing for displaying operational selections and range findings. An actuator is mounted adjacent the upper section and is operably connected to the signal emitting circuitry. The actuator is used to select desired operational selections displayed on the display device and actuating the signal emitting circuitry.

Abstract: A laser range finder includes a circular in-sight field of view which incorporates within it a magnified "TV view" of the target area with the TV view roughly approximating the rectangular shape of a standard television picture. Also within the circular field, over and under the TV view, are a target quality indicator, a range distance display, and other indicators. Within the TV view is a targeting reticle which indicates roughly the footprint of ranging laser pulses such that a target can be selected. The target quality indicator is a bar graph which displays the number of identifiable received reflected laser pulses from a series of such pulses emitted by the range finder. By aiming the range finder at various targets via the footprint reticle, repeatedly firing the range finder and monitoring the target quality graph for each firing, a user can move the range finder to find a surface proximate the target with a reflective quality sufficient to yield an accurate target range reading.

Abstract: A circuit and apparatus for generating a light pulse from an inexpensive light-emitting diode (LED) for an accurate distance measurement and ranging instrument comprises an LED and a firing circuit. An optional pre-biasing circuit provides a reverse-bias signal to the LED to ensure the LED does not begin to emit light before a firing circuit can provide a sufficiently high current pulse of short duration as a forward current through the LED. The LED is driven by the firing circuit with a pulse of high peak power and short duration. The resulting light pulse from the LED can be inexpensively used to derive distance and ranging information for use in a distance measurement and ranging device.

Abstract: A highly precise range measurement instrument is made possible through the use of a novel and efficient precision timing circuit which makes use of the instrument's internal central processing unit crystal oscillator. A multi-point calibration function includes the determination of a "zero" value and a "cal" value through the addition of a known calibrated pulse width thereby providing the origin and scale for determining distance with the constant linear discharge of capacitor.

Abstract: A modular laser-based surveying system is disclosed which comprises a laser-based distance measuring module and a separable compass module removably coupled to the laser based distance measuring module. Each of these modules may be operated as stand alone units as each has its own power supply and display. The system further may comprise a separate angle encoder module adapted to be coupled to either the laser distance measuring module or the compass module and a data logger or computer for processing data transmitted from any or all of the modules.

Abstract: A pre-biasing technique for a transistor-based avalanche circuit which improves the initial rate of rise in the current applied through a laser diode or other light emitting device in a laser based distance measurement and ranging instrument and, therefore, the sharpness of the leading edge of the laser pulse produced. Since the timing of the flight time of a laser pulse to a target and back to the ranging instrument is determined with reference to the leading edge of the emitted laser pulse, the inherent precision obtainable is enhanced by the production of a sharper leading edge pulse. Through the use of the pre-biasing technique disclosed, the very rapid rise time pulse which may be achieved also allows for the substitution of a much cheaper light emitting diode in lieu of a conventional laser diode in an alternative implementation of a light pulsed-based distance measuring and ranging instrument.

Abstract: A voltage conversion circuit for transforming an input voltage level at an input voltage node to a relatively higher output voltage level at an output voltage node with respect to a common reference voltage node includes an inductor coupling the input voltage node to the output voltage node and a signal source, such as a linear timer integrated circuit ("IC") supplying an output signal having alternating first and second states thereof. A bipolar switch having first and second current carrying terminals and a control terminal thereof has its first current carrying terminal coupled to the output voltage node and its control terminal coupled to receive the output signal from the signal source.

Abstract: An apparatus and method for accurately determining a target distance in adverse weather conditions utilizing both LASER and RADAR is disclosed. The radar signals are used to determine an approximate range which is then used as a gating window for the determination of which laser reflection is from the actual target as opposed to a reflection from the atmospheric interference. The method basically comprises the steps of initiating a radar pulse in the direction of a target and receiving a reflection, transmitting a laser signal and receiving a plurality of reflections, determining an approximate range based on the radar signals, and using this approximate range to ascertain which of the laser reflections is from the target. This determination is preferably made by generating a gating signal and gate width from the radar signals and passing the set of laser range signals through the gate to eliminate the false signals and select the signal that survives the gate as the accurate target range.

Abstract: A countermeasure-detecting circuit, and associated method, for a laser speed detector. Countermeasures taken at a moving target, such as a vehicle, to interfere with operation of the laser speed detector are detected. When countermeasures taken at the moving target are detected, the sensitivity of the laser speed detector is altered to overcome the effects of the countermeasures.