Trimble Navigation Limited

Trimble Inc.

Peter V Loomis

John F Schipper

James M Janky

Gregory C Best

John William Peake

Leonid Sheynblat

Chung Y Lau

Nicholas Charles Talbot

Shawn D Weisenburger

Richard W Rudow

Ralph Frederic Eschenbach

Dominic G Farmer

David R Gildea

Robert Wold

Venkateswaran Kasirajan

Peter Leroy Froeberg

Len Sheynblat

Paul E Braisted

Rudolph M Kalafus

Allan M Pelley

Charles Abraham

James Edwin Jones, Jr

Kevin McKenzie Reeds

K Tysen Mueller

Systems and methods for sharing convergence data between GNSS receivers are disclosed. Convergence data received at a GNSS receiver via a communication connection may be utilized to determine a position of the GNSS receiver.

Method and system for sharing convergence data

Dead reckoning combined with GNSS-aided map-matching improves accuracy and reliability of vehicle navigation. A map-match navigation module in a handheld device sends map-match feedback messages to a vehicle state estimator via a port. The module also accepts vehicle speed and inertial navigation data from sensors mounted in the vehicle.

Vehicle navigation by dead reckoning and GNSS-aided map-matching

Methods and apparati for representing and storing a sequence of digital data values so that, once stored in memory, a data value cannot be modified, or cannot be modified without detection. Detection of subsequent data alteration may use error checksums, storage of instrument data in different data fields, data constraint relations, data encryption techniques and/or comparison of instrument identification numbers. Where data are to be stored in non-alterable form, the number of elements used in representing the sequence is reduced or minimized. A data value sequence can be supplemented by one or more additional data values that are received and similarly stored, without changing any of the sequence of data values already stored. The instrument data values can be individual readout values or can be accumulated sums of data values. Some of the methods are exact, allowing reconstruction of any data value with zero error. Other methods are approximate but are less complex to apply. These methods can be applied to numerical readout values from instruments such as odometers and electropotential meters at a selected sequence of sampling times.

Authentication of accumulated instrument data

A method for enhancing the accuracy of location coordinates and/or clock bias computed for a mobile user station that is part of a Satellite Positioning System (SATPS), such as GPS or GLONASS. A data processing station is provided with pseudorange corrections PRC(t;j;ref) for an SATPS reference station for each of M SATPS satellites (j=1, . . . , M; M.gtoreq.3) and with uncorrected location fix coordinates x'(t.sub.f), y'(t.sub.f)', z'(t.sub.f)' and/or b'(t.sub.f) for the mobile station for a selected location fix time t.sub.f. A matrix equation H(t.sub.f ;mob).DELTA.W(t.sub.f ;mob)=PRC(t.sub.f ;ref) relates a matrix .DELTA.W of location fix coordinate corrections for the mobile station to a matrix PRC(t;ref) of the pseudorange correction values, where H(t.sub.f ;mob) is an M.times.N matrix (M.ltoreq.N; N=3 or 4) with known entries computed from mobile station data. An inverse or pseudo-inverse matrix H(t.sub.f ;mob).sup.(-1) is formed satisfying the relation H(t.sub.f ;mob).sup.(-1) H(t.sub.f ;mob)=the identity matrix I, and the matrix .DELTA.W(t.sub.f ;mob)=H(t.sub.f ;mob).sup.(-1) PRC(t.sub.f ;ref) is computed. The entries of the matrix .DELTA.W(t.sub.f) are interpreted as additive corrections for the location fix coordinates x'(t.sub.f), y'(t.sub.f)', z'(t.sub.f)' and/or b'(t.sub.f) for the mobile station. Post-processing can be performed to apply the pseudorange corrections to the mobile station data.

Post-processing of inverse DGPS corrections

Apparatus and method for determining the present location of a mobile user that carries the apparatus inside or outside buildings and structures within a region R. The apparatus includes a radio location determination (LD) signal module that receives radiowaves from at least three radio LD signal sources, such as FM carrier or subcarrier signals, and an outdoor LD signal module that receives outdoor LD signals from at three other satellite-based or ground-based outdoor LD signal sources, such as GPS, GLONASS or Loran-C signal sources. The radio LD signals and outdoor LD signals are used to (1) determine the location of the radio LD module, (2) determine the location of the outdoor LD module and (3) determine an indicium representing signal strength or signal quality for the radio LD signals and for the outdoor LD signals. The radio LD signal indicium and the outdoor LD signal indicium are compared with threshold values for these indicia, and at most one of the radio LD module location and the outdoor LD module location is selected as the present location of the apparatus user. The radio LD module and the outdoor LD module can be combined in a hybrid portable LD system, or the two modules can be separated from and move independently of each other.

Portable hybrid location determination system

A method for fast acquisition, in as little as 6-15 seconds, of signals from a satellite in a Satellite Positioning System (SATPS), such as GPS or GLONASS, that does not require permanent storage of satellite ephemeris information at an SATPS ground station. This SATPS signal acquisition method can be used whenever the 'new' station initially powers up or has lost lock on one or more SATPS signals that must be (re)acquired. A reference SATPS station provides the new SATPS station with an estimated reference station location and ephemeris information for one or more identified SATPS satellites visible from the reference station. The new station receives and uses this information to establish carrier frequency ranges to search for the identified SATPS satellite, by limiting the search to a reduced frequency range based upon estimated Doppler shift of SATPS signals received from this satellite. The actual frequency shift may differ from the estimated Doppler shift, due in part to errors in a frequency source used by the new station. When a first SATPS satellite signal is acquired and locked onto by the new station, the error in the new station frequency source is estimated, and the frequency range for searching for an SATPS signal from another satellite is reduced. Acquisition of additional SATPS satellite signals occurs more quickly. This system also allows the use of less accurate timing sources for the new stations. A new station need not store ephemeris information for the SATPS satellites but may call upon and use the ephemeris information available at the reference station.

Reduction of time to first fix in an SATPS receiver

Method and apparatus for providing GPS pseudorange correction information over a selected geographic region S with a diameter of up to 300 km with an associated inaccuracy no greater than 5 cm. N spaced apart GPS reference stations (N&gt;4), whose location coordinates (u.sub.n,v.sub.n,w.sub.n) are fixed and are known with high accuracy, are provided within or adjacent to the region R. Each reference station n(n=1, 2, . . . , N) receives GPS signals from at least four common-view GPS satellites, numbered m=1, 2, . . . , M (M.gtoreq.4), computes its own GPS-determined location coordinates, compares these coordinates with its known location coordinates, determines the pseudorange corrections PRC(t;t0;m;n) for its GPS-determined location, and transmits these correction signals to a central station located within or adjacent to the region S. The central station retransmits the pseudorange correction signals throughout the region S. A mobile GPS station within or adjacent to the region S has stored within it the coordinates (u',v',w') of the GPS-determined last location of that mobile station and the spatial coordinates (u.sub.n(k),v.sub.n(k),w.sub.n(k)) (k=1, 2 , . . . , K; K&gt;3) of K GPS reference stations within S that are closest to the last-determined location of that mobile station. The mobile station then computes the differential GPS corrections for the GPS-determined present location of that mobile station. Alternatively, the reference stations can transmit to the central station unprocessed GPS signals for determination of the pseudorange correction signals at the central station. This approach can be modified if the region R is two-dimensional, where only two coordinates u and v are needed, or if the region R is one-dimensional, where only one coordinate u is needed. Suitable algorithms for selection of the coefficients a.sub.k' are discussed.

Carrier phase differential GPS corrections network

A GPS-based integrated controller module combines in a single integrated package or module a GPS receiver, a map, and a logic or decision module which provides an output control signal or control code. The map of the integrated module provides various representations. Continuous functions are provided with various types of coordinate systems, which can use interpolation between reference points in a grid system, or Taylor series representations. The integrated module performs discrete output functions such as providing a control code or a user's location either within or out of a particular closed area or polygonal zone, where each location shares a common characteristics with the other locations in the zone.

GPS-based controller module

A method for determining J location fix coordinates, such as (x,y,z,b) for J=2-4, for a selected location, such as a mobile station location, with increased accuracy, for a satellite-based or ground-based location determination (LD) system such as GPS, GLONASS or LORAN. Pseudorange corrections for the pseudorange values measured at the reference station approximately at an observation time t' are used to correct the pseudorange values measured at the selected location. Location fix coordinates are computed from the pseudorange values at the selected location or at the reference station, using an exact, invertible transformation T(t') between the J location fix coordinates and J pseudorange values. Information including the location fix coordinates is transmitted from one station to another with a reduced or minimal number of information bytes and with small dynamic ranges. Locations fix coordinates, as corrected using the pseudorange corrections, for the selected location are computed at the selected location, at the reference station or at a supplemental data processor, using the transformation T(t') and/or its inverse.

Precise inverse differential corrections for location determination

Methods for authentication or validation of the location of a putative source (ps) of a message, using time varying location determination (LD) signals that are received from J sources (J&gt;1) of LD signals G(t;j;ps) that are spaced apart from the putative source. The putative source forms an augmented data signal that includes the original message, one or more segments g�t.sub.k(m),t.sub.k(m+1) ; j; ps!={G(t.sub.r ;j;ps).vertline.t.sub.k(m) .ltoreq.t.sub.r .ltoreq.t.sub.k(m+1) } of the LD signals for a selected time interval, a putative source asserted location L(t'.sub.k(m) ;ps) for a time t'.sub.k(m) in the selected time interval, and other identifying parameters. The augmented data signal is received by a central station that analyzes the LD signal segments and determines whether the asserted location L(t'.sub.k(m) ;ps) is likely to be the true message source location. Part or all of the augmented data signal can be encrypted for transmission. One application is validation of use of licensed software on a computer whose location may be mobile. Another application is validation of votes cast from a plurality of remote voting sites.

Authentication of a message source

A method for characterization of data measurements made on signals received from a plurality of SATPS satellites that facilitates post-processing of these data to determine pseudoranges, code phases, carrier phases, pseudorange rate corrections, carrier phase corrections, spatial location, velocity and time coordinates and other variables of interest for an SATPS user. The SATS may be any satellite-based location determination system, such as GPS or GLONASS. The approach uses six indices h1, h2, h3, h4, h5 and h6, with the first index h1 including the total solution coordinates (t.sub.n,x.sub.n,y.sub.n,z.sub.n) for the location fix time t=t.sub.n at which measurements are made, and the spatial location and velocity coordinates. The second and third indices h2 and h3 specify the in-view satellite constellation that provided the SATPS signals and the IODC parameter. The fourth index h4 represents the specific parameter set used to model the ephemeris, almanac and clock correction parameters needed for the M satellites for a given coordinate fix. The fifth index h5 represents the parameter set used to model signal propagation delay through the ionosphere and troposphere. The sixth index h6 represents the location solution method and method parameters used to determine the spatial location, location fix time, clock bias and/or velocity coordinates for each coordinate fix. For each time stamp value in the index h1, information specified by the six indices may be used to reconstruct the information needed to determine pseudoranges, pseudorange rates, carrier phase signals, corrections to these variables, and other quantities of interest in an SATPS. The information specified by the six indices may a minimal set in which information specified by one index is not also specified by another index. Another method uses selected portions of the information specified by the collective indices h1, h2, h3, h4, h5 and h6, using a collective index H that may be divided into index segments.

Compaction of SATPS information for subsequent signal processing

Post-processing of inverse differential corrections for SATPS mobile

An apparatus combining a handheld, electronic video game device, a location determination receiver, an electronic map and/or electronic yellow pages, and geocoding. The apparatus provides a user with his location and locations of map features and/or yellow page addresses proximate to his location. The handheld, electronic video game display displays the user's location and a map and/or yellow pages and hosts a memory cartridge that includes software for a user interface, for maps and/or yellow pages database, and for geocoding. The apparatus benefits from the high manufacturing and sales volumes of existing handheld games devices.

Growing community of inventors

Sunnyvale, CA, United States of America

Peter V Loomis