Abstract: A communication system, method, and multiple master and slave transceivers having automatic addressing and collision avoidance. A master transceiver is programmed with its address by a user through a host. After being turned on, a slave transceiver acquires its address as the address of the first message it receives from a master transceiver. The master and the slave transceivers then communicate in each direction and ignore other messages by using that address until the slave transceiver is turned off. When the slave transceiver is turned on again, it acquires a new address of the address of the first new message it receives from a master transceiver, not necessarily the same master transceiver. The transceivers communicate with a signal having an on-condition having different lengths for representing different symbols.

Abstract: A range pole and in-line detachable battery module assembly including a range pole (10) with an elongated tubular range pole shell (102) which has a female cap assembly (108) and a male cap assembly (26) at opposite ends. A detachable battery module (12) includes a tubular battery-module shell (24) which has a male cap (26) at one end that is adapted to mate with female cap assembly 108. A detachable tip (14) includes a ribbed aluminum tip body (150) having external ribs (152) formed in the sides thereof and a stainless steel tip (160). The male cap assembly (26) at the other end of the range pole (10) is to be used for connection to other equipment. In the present embodiment, the male cap assembly (26) at the top end of the range pole is coupled to a GPS antenna/receiver (16).

Abstract: A method and apparatus for processing multipath reflection effects in timing systems is disclosed in which a determination is made of whether a received signal is a reflected signal. A detector provides from an input signal a pair of signals representative of whether the input signal contained right-hand circularly polarized and left-hand circularly polarized components. The representative signals are separately processed in synchronized logic circuits to determine relative power levels. The power levels are compared to determine the nature of the dominant polarization of the input signal.

Abstract: The position, velocity, time (PVT) and attitude (ATT) measurement system including a Master GPS antenna and a plurality of Slave GPS antennas is disclosed. The system comprises a hardware PVT channel and a hardware ATT channel. After the Master GPS antenna is selected, the hardware PVT channel stays locked on the Master antenna during the measurement time thus optimizing the accuracy of the PVT data. The PVT channel performs the tracking of the visible GPS satellites and generates the tracking data and the PVT data. The ATT channel performs the attitude measurement using all Slave antennas and the PVT tracking data.

Abstract: A carrier ambiguity detector for resolving a 1/2cycle carrier phase ambiguity in an incoming GPS signal before the arrival of the next preamble by detecting a match or an inverted match between an internally stored expected data message and the incoming data in the remaining subframe before the arrival of the next preamble. The carrier ambiguity detector of the present invention includes a buffer for buffering incoming data, a data memory for storing time-tagged expected data, a data pointer for selecting certain expected data corresponding to a GPS-based time that is synchronized to the incoming data, non-inverting and inverting comparators for comparing the buffered data to the expected data, and a data compare detector coupled to the comparators for indicating a non-inverted or an inverted match for a zero degree or a one-hundred eighty degree resolution, respectively, of carrier phase information.

Abstract: A method and apparatus for providing a vehicle theft alarm using a handheld computing device. A handheld computing device is disclosed that includes an image capture device, a location determination system and a communication device. The handheld computing device can be used for capturing images and transmitting images to other locations via the communication device. The handheld computing device also includes a position determining system for determining position of the vehicle. The handheld computing device can be located within a vehicle and the alarm system activated such that, upon the occurrence of an alarm triggering event, the image capture device captures images of the driver's compartment of the vehicle and the location determination system determines the location of the vehicle. The captured images and the determined location are transmitted through the communication device to a designated remote location.

Abstract: A system and method for automated differential correction processing of field data in a global positioning system (GPS). In one embodiment, the present invention retrieves GPS field data collected by one or more GPS receivers from a storage device, and then automatically selects the most appropriate differential correction scheme to generate a solution without user intervention. More specifically, the present invention executes a code-based correction scheme to generate a code-based solution for the field data. Next, the present invention examines the field data to determine whether a carrier phase correction is applicable. If the field data supports carrier phase correction, the present invention generates a carrier phase solution, compares it with the code-based solution, and returns the more accurate of the two solutions as the final result. If the field data does not support a carrier phase correction, the present invention returns the code-based solution as the final result.

Abstract: A position identification system, that employs satellite navigational or similar positioning technology is provided. In one embodiment, the position identification system includes a receiver for receiving position signals from a positioning system; an orientation device that is configured to rotate about at least one axis; a pointing element coupled to the orientation device to provide indication of a direction to a desired position; and a processor that is coupled to the receiver to receive the position signals. The processor computes a current position of the position identification system based upon the position signals. The processor directs the orientation device, based upon the current position and the desired position, with the pointing device tracking the direction to the desired position as the current position changes. Using the positioning system, a pointing device is used to identify the direction to the desired location to the user of the positioning system.

Abstract: A tilt predictor incorporated into a total station to predict the degree of tilt of the rotational alidade portion of a total station corresponding to the rotational orientation of the rotational alidade portion. In one embodiment, the present invention defines the plane of rotation for the rotational alidade portion with the rotational alidade portion disposed in a first rotational orientation. The rotational alidade portion is then rotated to the desired rotational orientation. This embodiment then predicts the degree of tilt of the rotational alidade portion at the desired rotational orientation.

Abstract: A method and apparatus that allows for monitoring the operation and usage of a vehicle. A data logger is installed in a vehicle to be monitored. The data logger couples to the vehicle's electronic system and monitors data relating to usage and condition of the vehicle. In one embodiment, the data logger includes a position determining system for determining whether the vehicle has traveled outside of a predetermined area and accelerometers for determining whether the vehicle has been involved in a collision. The data logger transmits information relating to the condition and usage of a vehicle each time that a vehicle return to a facility. The information relating to the condition and usage of the vehicle is then coupled to a computer. This allows for easily monitoring the usage and condition of vehicles without requiring manual data entry.

Abstract: The apparatus and the method for analyzing the code multipath satellite disturbance are disclosed. The apparatus includes the tracking channel and the analyzing circuit. The tracking channel can include the weighted or modified weighting functions to decrease the level of the multipath reference signal. The analyzing circuit can include a plurality of additional correlator circuits used to build the filter function that is utilized to analyze the incoming code multipath disturbance.

Abstract: Methods for identification of, and compensation for, the effects of presence of a multipath signal in a received composite digital signal that includes a direct, distortion-free signal. A direct signal is additively or multiplicatively combined with a distinguishable indicium signal and the resultant signal is transmitted to a receiver. The indicium signal may be distinguished by use of a different frequency or by use of a bit pattern that cannot be included in a direct signal pattern. The receiver identifies the received indicium signal within the received signal, compares the received indicium signal with a reference signal that is substantially a replica of the transmitted indicium signal, determines what operations will convert the reference signal into the received indicium signal, and applies an inverse of these operations to the portion of the received signal that contains the received direct signal, to obtain an enhanced received direct signal with reduced multipath signal effects.

Abstract: A system for single frequency on-the-fly (OTF) real-time kinematic (RTK) centimeter level position determination using the satellite positioning system (SATPS) is disclosed. The system includes a storage buffer used for storing data. The stored data and the current data are used by an ambiguity search algorithm for the improved integer ambiguity resolution.

Abstract: A personal navigation device and method for providing location information. In one embodiment, the present invention is comprised of a portable hand-held unit. The portable unit contains a communication system adapted to receive data at and transmit data from the portable unit. The portable unit also contains a position determining system which determines the geographic location of the portable unit. The position determining system is connected to the communication system. A graphic display located on the portable unit is also connected to the position determining system. The graphic display displays a representation of the current location of the portable unit with respect to a previously selected location. In one embodiment, the representation of the current location also includes a representation of the speed and the heading of the portable unit with respect to the previously selected location.

Abstract: The present invention comprises a global positioning system (GPS) based augmented reality (AR) aircraft collision avoidance system. The system of the present invention includes a GPS receiver for receiving GPS signals and determining a present position using the GPS signals. The system of the present invention also includes an automatic dependent surveillance (ADS-B) receiver for receiving an ADS-B signal from an aircraft. The system of the present invention further includes an AR visor coupled to both the GPS receiver and the ADS-B receiver. The AR visor receives the present position from the GPS receiver and receives the ADS-B signal from the ADS-B receiver. Using the present position and the ADS-B signal, the AR visor determines a three dimensional bearing to the aircraft. The AR visor is adapted to be worn by a user.

Abstract: The present invention involves a system and method for determining a position of an object. The system comprises at least one ground transmitter configured to generate ground transmitter position signals comprising position information. The at least one ground transmitter has a known position. The system also comprises at least one ground transceiver having a known position and configured to receive the ground transmitter position signals and transmit ground transceiver position signals that are synchronized to the clock of the at least one ground transmitter. The object is configured to receive the ground transmitter position signals, the ground transceiver position signals and calculate the position of the object based on the received signals and the known positions of the at least one ground transmitter and the at least one ground transceiver.

Abstract: A GPS/GSM receiver combination for receiving GSM and GPS signals using an RF GPS integrated circuit for downconverting the GPS signal. The GPS integrated circuit includes a synthesizer for generating LO signals, first and second downconverters for using the LO signals for downconverting the GPS signal, and a sampler for providing in-phase and quadrature phase sampled output signals representative of the GPS signal. The synthesizer includes a multi-mode divider for providing substantially the same first LO frequency at about the midpoint of the L1 and L2 GPS frequencies when either of a standard GSM reference frequency or historically common GPS reference frequency is selected. A standby mode in the integrated circuit is controlled by a power logic circuit using a power supply input as a logic control signal.

Abstract: An audible signal generator incorporated into a total station to audibly indicate to the user the rotational orientation of the total station, and a method for using the audible indication to perform the tilt sensor calibration. In one embodiment, the present invention indicates to the user of the total station when the tilt sensor has been calibrated with the total station in a first rotational orientation. This embodiment then audibly indicates to the user when the rotational alidade portion of the total station has been rotated to a second rotational orientation. This embodiment then audibly indicates to the user when the tilt sensor has been calibrated with the total station in the second rotational orientation.

Abstract: A circuit for storing GPS data gathered in the field is described. The stored data is later used to test the ability of GPS processing circuits to handle GPS data containing multipath interference and dropouts.

Abstract: A GPS receiver including an RF GPS integrated circuit downconverter having a standby mode controlled by a power supply input used as a logic signal. The RF GPS integrated circuit includes a synthesizer for generating LO signals, first and second downconverters for using the LO signals for downconverting the GPS signal, and a sampler for using a clock signal for providing in-phase and quadrature phase sampled output signals representative of the GPS signal. The synthesizer includes a multi-mode divider for providing substantially the same first LO frequency at about the midpoint of the L1 and L2 GPS frequencies when either of an external or internally generated reference frequency is selected. A GPS digital signal processor integrated circuit issues the logic signal and the clock signal from a single pin.