Novariant, Inc.

Integrinautics Corporation

H Stewart Cobb

Kurt R Zimmerman

David G Lawrence

Paul Y Montgomery

Michael Lee O'Connor

Jamal Izadian

Glen Alan Sapilewski

Lars G Leckie

Frank N Bauregger

Dave Lawrence

Avi Gross

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.

Satellite and local system position determination

To provide sub-meter accuracy in a local positioning system, ranging signals with a high modulation rate of code, such as 30 MHz, or more are transmitted. Code phase measurements may be used to obtain the accuracy without requiring relative motion or real time kinematic processing. The ISM or X-band is used for the carrier of the code to provide sufficient bandwidth within available spectrums. The length of codes used is less than or about a longest length across the region of operation, such as less than 15 kilometers in an open pit mine. The spread spectrum codes from different land-based transmitters are transmitted in time slots pursuant to a time division multiple access scheme for an increase in dynamic range. To avoid overlapping of code from different transmitters, each time slot includes or is separated by a blanking period. The blanking period is selected to allow the transmitted signal to traverse a region of operation. Differential measurements of signals received at a base station and a mobile receiver may improve accuracy.

Land-based local ranging signal methods and systems

In a local positioning system, a receiver is adapted for receiving signals from a land-based transmitter. The receiver includes an analog decorrelator for decorrelating the transmitted spread spectrum signals. A down converter connected with an antenna may be spaced away from other portions of the receiver. The down converter down converts received ranging signals and provides them to the remotely spaced receiver portions. A signal line connecting the down converter to the receiver may be operable to transmit any two or more of a reference signal provided to the down converter, the down converted intermediate frequency signals provided to the receiver, and power provided to the down converter. The receiver may be positioned adjacent to or as part of a land-based transmitter. By determining positions of two or more antennas, the location of the associated transmitter is determined.

Analog decorrelation of ranging signals

Methods and receivers determine a range from radio frequency ranging signals at multiple frequencies. The number of dedicated RF sections and correlation processing power is reduced by multiplexing signals from a sub-set of frequencies onto a common path. The common path provides shared processing, such as down-conversion shared by signals at two different frequencies. The correlation processing power for a three frequency receiver may be the same or similar as for a two frequency receiver since signals for two frequencies share processing as a function of time. Correlation is performed intermittently for signals at two of the frequencies.

Signal path system and method for a ranging signal receiver

Multiple frequency antenna structures and methods for receiving navigation or ranging signals

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.

Rebroadcasting method and system for navigation signals

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.

Multiple antenna multi-frequency measurement system

A satellite navigation system using multiple antennas for providing the position of multiple fiduciary points on an object even when fewer than four satellites are visible to some or all the antennas. Satellite signals from the multiple antennas are fed into at least one receiver. The receiver or receivers utilize constraint information, which is independent of the satellite signals. These external constraints are used to augment the signals received from the satellites, to obtain the position solution for each antenna. In a preferred embodiment, a common reference clock is used to provide an external constraint. Examples of other external constraints that can be used in the current invention are distance between the antennas, inertial measurement of attitude, rotational or linear position sensors, etc.

Satellite navigation system using multiple antennas

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.

System and method for land-leveling

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.

Growing community of inventors

Palo Alto, CA, United States of America

H Stewart Cobb