Abstract: A device for detecting the relative position of a generally horizontal reference plane of light includes a plurality of photodetector elements, a weighting circuit, and an output circuit. The photodetector elements are positioned on the device in a generally vertically oriented row. The weighting circuit provides a portion of the electrical output of each photodetector element as a first reference signal related to the spacing of the photodetector element from a first end of said row, and a portion of the electrical output of each photodetector element as a second reference signal related to the spacing of the photodetector element from the second end of said row. The output circuit is responsive to the weighting circuit for determining the relative levels of the first and second reference signals and the position of said reference plane of light with respect to the detector device.

Abstract: Field-deployable spatial positioning or measurement systems are provided for improved versatility, reliability and performance. The spatial positioning or measurement systems use rotating laser fans or beams for positioning and measuring and include a system integrated field-deployable length standard that uses a reelable tape with positional indents. The systems further include the use of labyrinth seals at interface volumes between rotating laser heads and transmitter assemblies to prevent ingress of contaminants and allow for elimination of the use of rotary seals. Further, new dynamic leveling techniques are provided to plumb positional laser transmitter systems. Still further, strobe beam configurations are provided for improved near/far performance and a vertical mode sensing scheme that allows switching to measuring tall structures when needed.

Abstract: Methods and apparatus are described and illustrated for producing GPS corrections, comprising: collecting measurements from a plurality of network reference stations; determining network corrections from the measurements; determining residual errors at one or more vernier-cell reference stations; and preparing vernier-cell corrections to compensate the residual errors within a vernier-cell region. Network correction streams are described and illustrated which contain network corrections derived from a plurality of network reference stations and residual error corrections derived from one or more vernier-cell reference stations. Methods and apparatus are described for employing such network correction streams in a virtual reference station to produce corrections and/or virtual measurements for use in a GPS receiver.

Abstract: A method for inferring useful information from position related vehicular events uses allows a vehicle to determine an arrival at a job site, without knowing the job site location in advance. Arrival information can be reported or downloaded later. The method predicts arrival using a series of implied rules. The rules are based on trigger events detected by a sensor and microprocessor installed in the vehicle monitors for the occurrence of a trigger event that indicates that work is about to commence. Such trigger events can also be unique vehicular activities indicative of work commencement.

Abstract: A method for satellite receiver autonomous integrity monitoring (RAIM) real time fault detection and exclusion implementation comprising the following steps: (1) continuously computing a horizontal protection level (HPL) and a vertical 32 protection level (VPL) associated with the effective configuration of real time measurement geometry; (2) if the HPL is less than or equal to the horizontal alert limit (HAL), and/or if the VPL is less than or equal to said vertical alert limit (VAL); declaring the RAIM detection function available; (3) continuously computing a horizontal exclusion level (HEL) and continuously computing a vertical exclusion level (VEL) associated with the effective configuration of real time measurement geometry; and (4) if the HEL is less than or equal to the HAL, and/or if the VEL is less than or equal to the VAL, declaring the RAIM fault exclusion function available.

Abstract: A Land Surveyor System with Reprocessing is carried by a surveyor moving from a first known position at the start of a survey interval to a second known position at the end of the survey interval has an AINS (aided inertial navigation system) that provides a continuing sequence of time-indexed present position values. A Position Computing System uses a program that stores the sequence of time-indexed present position values in a memory. A reprocessing computer and program is activated at the second known position to access and process the continuing sequence of time-indexed present position values with a smoothing program to provide indexed and adjusted present position values for at least some of the time-indexed present position values. The system is packaged for transport and use by a surveyor. A switch permits the surveyor to signal that the unit is stationary as a reset for the AINS.

Abstract: A method for simultaneously determining respective scale factors and alignment angles of a multi-axis accelerometer device for measuring acceleration. To measure the scale factors, the multi-axis accelerometer device to be calibrated is mounted on a turntable. The turntable has a tilt angle with respect to a vertical axis defined by the local gravity vector. The turntable is used to spin the multi-axis accelerometer device around an axis of rotation at an angular velocity such that the multiple sensitive axes of the accelerometer device experience a time varying component of the local gravity vector. The respective outputs of the multiple sensitive axes of the accelerometer device are recorded as the device experiences the time varying component of the local gravity vector. The multi-axis accelerometer device is mounted on the turntable in two more orthogonal orientations, and the rotation and data recording procedure is repeated. The angular velocity can be constant during the logging.

Abstract: A cellular telephone having a global positioning system (GPS) receiver using a blended combination of GPS signals from GPS satellites and GPS pseudolites for determining a location. The cellular transceiver receives wireless downlink cellphone signals having acquisition aiding information including GPS-based time; ephemeris orbital parameters for GPS satellites; and pseudorandom (PRN) codes, locations, and signal characteristics used by GPS pseudolites in the local vicinity. The GPS receiver in the cellular telephone uses the acquisition aiding information for speeding the time to the first location fix.

Abstract: A method for substituting at least one high quality position measurement with a set of upgraded low quality position measurements comprising the steps of: selecting a high quality source of position measurements of an object; obtaining at least one high quality position measurement of the object by using the high quality source; wherein each high quality position measurement of the object satisfies the threshold of acceptability requirement for the object; saving at least one high quality position measurement of the object taken at at least one high quality epoch timing coordinate; selecting a low quality source of position measurements of the object; obtaining at least one low quality position measurement of the object using the low quality source; if at least one high quality position measurement of the object is available and substantially recent, using at least one high quality position measurement of the object for navigation purposes of the object; if each high quality position measurement of the object

Abstract: An integrated position and direction system is disclosed that includes a digital compass, a communication module, and a satellite positioning system having a receiver adapted to receive satellite position determining signals. Signals that are received from satellites are used to determine position of the integrated position and direction system. A method for updating data is disclosed in which the integrated position and direction system communicates with a remote site and sends a determined position to the remote site. A response is generated and is transmitted to the integrated position and direction system that includes data relating to features located near the determined position. The received data is used to generate a display that indicates the position and the orientation of the features relative to the integrated position and direction system.

Abstract: A method and apparatus for generating signals that can be used for accurately determining position and a method and apparatus for accurately determining position. A radio station modification unit is disclosed that can be incorporated into an existing radio transmission facility. The radio station modification unit generates a correction data signal that can be used by position determining systems for accurately determining position. In one embodiment, the radio station modification unit generates correction data that is encrypted. A position determination system decrypts the correction data upon receiving an activation instruction and uses the correction data to accurately determine position.

Abstract: The present invention is a portable motion-activated position reporting device. In one embodiment, a controller is coupled with a power source, a position determining component, a wireless communications component, and an initiating component. In one embodiment, the initiating component detects motion of the position reporting device and generates a signal to the controller indicating the motion. The controller, in response to the signal, activates the position reporting device.

Abstract: Methods and apparatus are described and illustrated for producing GPS corrections, comprising: collecting measurements from a plurality of network reference stations; determining network corrections from the measurements; determining residual errors at one or more vernier-cell reference stations; and preparing vernier-cell corrections to compensate the residual errors within a vernier-cell region. Network correction streams are described and illustrated which contain network corrections derived from a plurality of network reference stations and residual error corrections derived from one or more vernier-cell reference stations. Methods and apparatus are described for employing such network correction streams in a virtual reference station to produce corrections and/or virtual measurements for use in a GPS receiver.

Abstract: A method for improving a satellite receiver autonomous integrity monitoring (RAIM) availability and fault detection and exclusion (FDE) function by using an adaptive threshold logic. The method comprises the following steps: (A) pre-computing a database of thresholds; (B) selecting in real time from the database a plurality of thresholds corresponding to a set of available measurements; and (C) determining an optimum RAIM/FDE function corresponding to the set of available measurements by using the adaptive threshold logic that utilizes the plurality of thresholds corresponding to the set of available measurements. The set of available measurements is selected from the group consisting of: {a GPS measurement, a GLONASS measurement, a GALILEO measurement, a baro measurement, a clock measurement, and a pseudolite measurement}.

Abstract: A method and apparatus for coupling data between communication devices in which data is transmitted over unoccupied radio channels. Multiple radio channels are monitored by a first communication device and a radio channel or a sequence of radio channels is assigned that is unoccupied. A message is then transmitted by the first communication device that includes the assigned radio channel or assigned sequence of radio channels. The first communication device then changes the radio channel to the assigned radio channel or the next channel in the assigned sequence of radio channels. The second communication device receives the transmission and also moves to the assigned radio channel or the next channel in the assigned sequence of radio channels. The process is repeated such that transmissions are over unoccupied radio channels. This results in both the first communication device and the second communication device “hopping” from channel to channel for communicating messages.

Abstract: A combined satellite positioning and electro-optical total station system includes a reference oscillator that provides local oscillator signals for a satellite navigation receiver and a precision frequency source for use by an electronic distance meter. When the satellite navigation receiver is locked onto and tracking orbiting navigation satellites, the highly precise cesium-rubidium clocks in the navigation satellite system can be used as standards to control the reference oscillator in the combined satellite positioning and electro-optical total station system. Baseline measurements made by the electronic distance meter are therefore not subject to mis-calibrations and drift as long as the satellite navigation receiver is locked onto and tracking the orbiting navigation satellites.

Abstract: A database reporting and data mining system operates in one embodiment on a database of a location aware wireless gateway that processes message, location, event data obtained from an asset sensor or user, and other telemetry data from remote assets such as vehicles of a business enterprise fleet, and presents configurable reports on web pages displayed within the user's web browser in text or chart form. Reports, which may be user-customized, are created in response to user queries regarding, e.g., activity, and trends and summaries of activity for individual vehicles or an entire fleet. Database-stored event data grouped by relationship, e.g., start and end events, enable automatic computation of desired information such as time and distance between events. Report data in XML format are re-formatted in XSL stylesheets.

Abstract: A laser level with a sensorless DC motor controller having a feedback sampling circuit connected in parallel with the coil to sense back EMF. An integrator provides a feedback signal from the sensed back EMF, which the amplified difference from a reference level is used as a pulse width control signal. A pulse width modulation generator uses the control signal to generate variable “on” time pulse widths for each motor drive pulse such that high resolution is provided to the DC motor, permitting accurate rotor position at low rotational speeds. It is emphasized that this abstract is provided to comply with the rules requiring an abstract to allow a searcher or other reader to quickly ascertain the subject matter of the technical disclosure. It is submitted with the understanding that is will not be used to interpret or limit the scope or meaning of the claims.

Abstract: Receiver circuits are provided for detecting a target light source. The circuits include a photocell arranged to detect light impinging thereupon, and a biasing circuit that maintains a constant reverse voltage across, the photocell irrespective of the photocell output. This maintains the capacitance of the photocell at a substantially constant value, and results in faster response times from the photocell. Further, the present invention provides circuits for effectively removing ambient conditions such as daylight from the output. Also, the present invention reduces the amount of signal loss between the photocell output and an amplifier due to loading at the input stage of the amplifier.