Abstract: A precise positioning method and system is disclosed for allowing an array of ground transmitters to self-survey their relative location at centimeter-level accuracy by transmitting, amongst the ground transmitters in the array, bi-directional ranging signals associated with a wideband code modulation with a chipping rate faster than 30 MHz.

Abstract: A “synchrolite” or rebroadcasting device allows GPS or GNSS navigation signals received at one or several locations to be processed at a separate location. The signals received by the synchrolite are added to a pilot tone and then encoded with a superimposed spread-spectrum code before being rebroadcast. The superimposed code allows signals from different synchrolites to be distinguished during the navigation process.

Abstract: A measurement system and an associated method for determining the positions of multiple antennas to centimeter level accuracy. A plurality of first filters, one filter for each antenna of a plurality of antennas, are each operable to obtain information from a respective one of the plurality of antennas at a primary frequency. A second filter connects with at least one of the plurality of antennas. A processor calibrates biases for the information at the primary frequency with a RF path bias calibration algorithm as a function of an output of the second filter.

Abstract: In a local positioning system, augmentation of the land-based system is provided by receiving signals from a GNSS. The signals from the land-based positioning system have a code phase accuracy better than one wavelength of a carrier of the signals from the GNSS. Different decorrelation may be used for signals from a satellite than from a land-based transmitter, such as using a digital decorrelator for signals from the satellite and an analog decorrelator for signals from a land-based transmitter. The receivers may include both a GNSS antenna and a local antenna. The phase centers of the two antennas are within one wavelength of the GNSS signals from each other. The local antenna is sized for operation in the X or ISM-bands of frequencies. The GNSS antenna is a patch antenna where the microwave antenna extends away from the patch antenna in at least one dimension.

Abstract: A measurement system and an associated method for determining the positions of multiple antennas to centimeter level accuracy. The system involves minimal incremental hardware cost per additional antenna to be tracked. The primary frequency RF signals are processed by a primary frequency RF section dedicated to each antenna. The secondary frequency RF signals from all the antennas are multiplexed and input to a secondary frequency RF section corresponding to each secondary RF frequency. A correlator derives code and carrier phase for the processed primary and secondary frequency RF signals. A processor thereafter reconstructs the carrier phase for the secondary frequency RF signals. The processor finally uses these reconstructed phases to resolve carrier cycle ambiguities and to determine the position of the antennas.

Abstract: Apparatus and methods for resolving integer ambiguities in position determination. An embodiment of the invention includes a reference system, augmented with multi-frequency pseudolites using a carrier phase differential GPS implementation, and a mobile system. In one embodiment, the components of the reference system includes one or more multi-frequency pseudolites, one or more multi-frequency reference receivers, a data link standing alone or built into the pseudolites, and the associated antennae for each of these elements. The components of the reference system may be stationary. The mobile system may include a multi-frequency receiver and its associated antennae. Because the mobile systems may passively receive information, an unlimited number of mobile systems may be included in any given embodiment of the invention.

Abstract: Apparatus and methods for resolving integer ambiguities in position determination. An embodiment of the invention includes a reference system, augmented with multi-frequency pseudolites using a carrier phase differential GPS implementation, and a mobile system. In one embodiment, the components of the reference system includes one or more multi-frequency pseudolites, one or more multi-frequency reference receivers, a data link standing alone or built into the pseudolites, and the associated antennae for each of these elements. The components of the reference system may be stationary. The mobile system may include a multi-frequency receiver and its associated antennae. Because the mobile systems may passively receive information, an unlimited number of mobile systems may be included in any given embodiment of the invention.

Abstract: A land-leveling system that uses the Global Positioning System is provided. The system provides for an earth-moving machine mounted with an antenna that receives GPS signals from the satellites of the Global Positioning System. The earth-moving machine comprises a vehicle attached to a work implement, which is also connected to an actuator. A decision unit mounted on the vehicle sends control signals to the actuator, which controls the elevation of the work implement. These control signals are generated using the signals received from the antenna and the desired grade map. This system has an increased coverage area, more accuracy and round-the-clock operability. The system could be used to carry out all the land-leveling operations viz. surveying, leveling and verifying.

Abstract: A measurement system and an associated method for determining the positions of multiple antennas to centimeter level accuracy. The system involves minimal incremental hardware cost per additional antenna to be tracked. The primary frequency RF signals are processed by a primary frequency RF section dedicated to each antenna. The secondary frequency RF signals from all the antennas are multiplexed and input to a secondary frequency RF section corresponding to each secondary RF frequency. A correlator derives code and carrier phase for the processed primary and secondary frequency RF signals. A processor thereafter reconstructs the carrier phase for the secondary frequency RF signals. The processor finally uses these reconstructed phases to resolve carrier cycle ambiguities and to determine the position of the antennas.

Abstract: A method and a system for L1/L2 phase and magnitude determination in satellite navigation equipment is disclosed herein. The method generates separate W code estimates for the L1 signal and the L2 signal, the estimates being uncorrelated with the error in the inphase and the quadrature components of the corresponding signals. The W code is estimated using both the L1 signal as well as the L2 signal. The L1 and L2 baseband signals are obtained from the corresponding RF signals. The baseband signals are added and then filtered using a non-causal FIR LPF. This filter has the property that the output at a time instant is uncorrelated with the input at that time instant. In the preferred embodiment, a one-W-code-bit I&D filter is used instead of a FIR LPF. In an alternate embodiment, a single W code estimate is obtained for both the L1 and the L2 signal.

Abstract: Apparatus and methods for resolving integer ambiguities in position determination. An embodiment of the invention includes a reference system, augmented with multi-frequency pseudolites using a carrier phase differential GPS implementation, and a mobile system. In one embodiment, the components of the reference system includes one or more multi-frequency pseudolites, one or more multi-frequency reference receivers, a data link standing alone or built into the pseudolites, and the associated antennae for each of these elements. The components of the reference system may be stationary. The mobile system may include a multi-frequency receiver and its associated antennae. Because the mobile systems may passively receive information, an unlimited number of mobile systems may be included in any given embodiment of the invention.

Abstract: Apparatus and methods for resolving integer ambiguities in position determination. An embodiment of the invention includes a reference system, augmented with multi-frequency pseudolites using a carrier phase differential GPS implementation, and a mobile system. In one embodiment, the components of the reference system includes one or more multi-frequency pseudolites, one or more multi-frequency reference receivers, a data link standing alone or built into the pseudolites, and the associated antennae for each of these elements. The components of the reference system may be stationary. The mobile system may include a multi-frequency receiver and its associated antennae. Because the mobile systems may passively receive information, an unlimited number of mobile systems may be included in any given embodiment of the invention.

Abstract: Disclosed herein is a system for rapidly resolving position with centimeter-level accuracy for a mobile or stationary receiver [4]. This is achieved by estimating a set of parameters that are related to the integer cycle ambiguities which arise in tracking the carrier phase of satellite downlinks [5,6]. In the preferred embodiment, the technique involves a navigation receiver [4] simultaneously tracking transmissions [6] from Low Earth Orbit Satellites (LEOS) [2] together with transmissions [5] from GPS navigation satellites [1]. The rapid change in the line-of-sight vectors from the receiver [4] to the LEO signal sources [2], due to the orbital motion of the LEOS, enables the resolution with integrity of the integer cycle ambiguities of the GPS signals [5] as well as parameters related to the integer cycle ambiguity on the LEOS signals [6].

Abstract: A differential carrier phase GPS navigational device comprises an integer estimator ?32! adapted to estimate an integer that resolves an integer cycle ambiguity, a reference phase predictor ?30! adapted to predict a present reference phase value from reference phase information received by a data link receiver ?22!, and a position calculator ?28! for computing a present vehicle position from the estimated integer, the predicted present reference phase value, and GPS signals received at a vehicle GPS receiver ?20!. The reference phase predictor ?30! comprises electronic circuitry adapted to determine a polynomial function which fits the reference phase information, and to evaluate the polynomial function to determine the predicted reference phase value. Because the position calculator uses a reference phase value that is not delayed, the navigational device is able to provide a vehicle position that corresponds to the present time.

Abstract: A GPS system and method for generating precise position determinations. The GPS system includes a ground based GPS reference system which receives with a reference receiver GPS signals and makes phase measurements for the carrier components of the GPS signals. The GPS reference system then generates and broadcasts an initialization signal having a carrier component and a data link signal having a data component. The data component of the data link signal contains data representing the phase measurements made by the reference receiver. The GPS system also includes a GPS mobile system which receives with a mobile position receiver the same GPS signals as were received by the reference system. In addition, the GPS position receiver receives the data link and initialization signals broadcast by the reference system.

Abstract: A GPS system and method for generating precise position determinations. The GPS system includes a ground based GPS reference system which receives with a reference receiver GPS signals and makes phase measurements for the carrier components of the GPS signals. The GPS reference system then generates and broadcasts an initialization signal having a carrier component and a data link signal having a data component. The data component of the data link signal contains data representing the phase measurements made by the reference receiver. The GPS system also includes a GPS mobile system which receives with a mobile position receiver the same GPS signals as were received by the reference system. In addition, the GPS position receiver receives the data link and initialization signals broadcast by the reference system.