Abstract: Methods, apparatus, and systems for determining the relevance of points of interest for a user are described. An application server receives information about a user's location, and velocity, as well as other user preferences, and adjusts a search space and filters points of interest identifying those that are relevant to the user. The relevance of the points of interest are based on the user's route, location and velocity.

Abstract: A method for measuring positional changes of an object, including rotation about any or all of three axes, using linear accelerometers. There is disclosed a method of using a linear accelerometer to integrate two other 3D linear accelerometers in order to measure and supply for further use six-dimensional information, that is, translation in three dimensions and rotation about three axes. Two linear accelerometer sensors are used to determine all but one of the variables in the six degrees of freedom. Output from a third accelerometer generates the data need to determine a sixth, rotational, degree of freedom. The need for a gyroscope for detecting changes in heading (i.e., yaw of azimuth) may therefore be avoided.

Abstract: Signal acquisition assistance data is obtained for receiving devices such as wireless position assisted location devices seeking signals from any source, such as satellite vehicles and base stations. The data may be obtained from previously acquired data, based upon evaluation of changes in parameters such as time and location that may jeopardize validity. In some cases the data may be adjusted for the changes in parameters. Refined data may be calculated by a receiver using partial measurements of signal sets, particularly if the acquisition assistance data provided by a remote entity includes more distinct parameters than have typically been provided. New data need not be obtained until the validity of previous data expires due to limitations upon temporal extrapolation using Doppler coefficients, unless mobile station movement that cannot be compensated is detected, and jeopardizes validity of the previous data.

Abstract: Methods, apparatus, and systems for determining the relevance of points of interest for a user are described. An application server receives information about a user's location, and velocity, as well as other user preferences, and adjusts a search space and filters points of interest identifying those that are relevant to the user. The relevance of the points of interest are based on the user's route, location and velocity.

Abstract: The partial decoding algorithm for decoding the partially damaged differential satellite positioning system (SATPS) messages is disclosed. The algorithm is based on the modified parity test. The information included in the decoded messages can be used for the high level differential SATPS testing.

Abstract: Methods for determining integrity of pseudorange and pseudorange rate signals received from a plurality of M Satellite Positioning System satellites (including GPS and GLONASS), numbered j=j1, j2, . . . , jM, at a reference SATPS station (RS), using pseudorange or pseudorange rate signals received from the same satellites at a nearby signal integrity monitoring (SIM) station. Pseudorange correction values or, alternatively, pseudorange rate correction values, for SATPS signals received at an RS station and at the corresponding SIM station are computed, and difference values between the RS and SIM values are computed for each satellite. If the magnitude of each difference is less than a selected threshold difference, pseudorange corrections or pseudorange rate corrections for that reference station can be used by a nearby mobile station to differentially correct the mobile station location fix coordinates or velocity fix coordinates.

Abstract: Method and apparatus for reducing the contributions of ionospheric propagation time delay error, multipath signal error and receiver noise error from signals received in a Satellite Positioning System (SATPS) from one or more SATPS satellites by formation and appropriate filtering of differences of signals DD that are differences of SATPS signals received by the SATPS receiver/processor. A difference signal DD of code-phase-derived, ionosphere-free signals and carrier-phase-derived, ionosphere-free signals is formed, and this difference signal is passed through a first statistical processing filter with an associated time constant .tau.1 in the approximate range 50-500 sec, to produce smoothed or filtered first difference signal with the estimated receiver noise error reduced or removed. The difference signal DD is passed through second and third statistical processing filters having associated time constants .tau.2=5-20 sec and .tau.

Abstract: 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>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.

Abstract: The partial decoding algorithm for decoding the partially damaged differential SATPS messages and the decoding device is disclosed. The algorithm is based on the modified parity test. The information contained in the decoded messages is used for the high level differential SATPS testing.

Abstract: A method for compensating for temporary loss of differential GPS correction signals for a satellite, numbered j, during an IODE changeover interval. Differences .DELTA.e.sub.i (t;j;n+1,n)=e.sub.i (t;j;n+1)-e.sub.i (t;j;n) (i=1, . . . , I) are formed for I ephemeris parameters used to describe the ephemeris for the satellite (j) during IODE intervals number n+1 and n. These differences are approximated for a DGPS blank-out time interval, given by t(j;n+1).sub.IODE .DELTA.t.sub.rev,mob .ltoreq.t<t(j;n+1).sub.IODE +.DELTA.t.sub.ch +.DELTA.t.sub.rev,ref, during which a GPS reference station continues to broadcast DGPS correction information based on the old ephemeris data that was valid during the preceding IODE time interval, given by t(j;n).sub.IODE .ltoreq.t<t(j;n+1).sub.IODE. These ephemeris differences are used by a mobile station that receives DGPS correction information from the GPS reference station to produce corrected GPS information for a blank-out time interval.

Abstract: A method for compensating for temporary loss of differential GPS correction signals for a satellite, numbered j, during an IODE changeover interval. Differences .DELTA.e.sub.i (t;j;n+1,n)=e.sub.i (t;j;n+1)-e.sub.i (t;j;n) (i=1, . . . , I) are formed for I ephemeris parameters used to describe the ephemeris for the satellite (j) during IODE intervals number n+1 and n. These differences are approximated for a DGPS blank-out time interval, given by t(j;n+1).sub.IODE .DELTA.t.sub.rev,mob .ltoreq.t<t(j;n+1).sub.IODE +.DELTA.t.sub.ch +.DELTA.t.sub.rev,ref, during which a GPS reference station continues to broadcast DGPS correction information based on the old ephemeris data that was valid during the preceding IODE time interval, given by t(j;n).sub.IODE .ltoreq.t<t(j;n+1).sub.IODE. These ephemeris differences are used by a mobile station that receives DGPS correction information from the GPS reference station to produce corrected GPS information for a blank-out time interval.

Abstract: Method and apparatus for reducing the contributions of receiver noise signal error and multipath signal error from signals received in a Satellite Positioning System (SATPS) from one or more SATPS satellites by formation and appropriate filtering of differences of signals DD that are differences of SATPS signals received by the SATPS receiver/processor. A difference signal DD of code-phase-derived delta range signals and carrier-phase-derived delta range signals is formed, and this difference signal is passed through a first statistical processing filter with an associated time constant .tau.1 in the approximate range 50-[500] 100 sec, to produce smoothed or filtered signal with the estimated receiver noise error reduced or removed. The difference signal DD is passed through second and third statistical processing filters having associated time constants .tau.2=5-20 sec and .tau.

Abstract: Method and apparatus for reducing the contributions of receiver noise signal error and multipath signal error from signals received in a Satellite Positioning System (SATPS) from one or more SATPS satellites by formation and appropriate filtering of differences of signals DD that are differences of SATPS signals received by the SATPS receiver/processor. A difference signal DD of code-phase-derived delta range signals and carder-phase-derived delta range signals is formed, and this difference signal is passed through a first statistical processing filter with an associated time constant .tau.1 in the approximate range 50-500 sec, to produce smoothed or filtered signal with the estimated receiver noise error reduced or removed. The difference signal DD is passed through second and third statistical processing filters having associated time constants .tau.2=5-20 sec and .tau.

Abstract: Methods for determining the integrity of pseudorange and pseudorange rate signals received from a plurality of M Satellite Positioning System satellites (SATPS, including GPS and GLONASS), numbered j=j1, j2, . . . , jM, at a reference SATPS station (RS), using pseudorange and pseudorange rate signals received from the same satellites at a signal integrity monitoring (SIM) station located near the reference station. Pseudorange correction values PRC(t;i;j).sub.RS and PRC(t;i;j).sub.SIM and pseudorange rate correction values PRRC(t;i;j).sub.RS and PRRC(t;i;j).sub.SIM for the signals received at the reference station (RS, number i) and at the SIM station are computed, and difference values DPRE(t;i;j)=PRC(t;i;j).sub.RS -PRC(t;i;j).sub.SIM and DRRE(t;i;j)=PRRC(t;i;j).sub.RS -PRRC(t;i;j).sub.SIM are computed from these correction values. If .vertline.DPRE(t;i;j).vertline..ltoreq.DPRE(i;j).sub.thr and .vertline.DPRRE(i;j).vertline..ltoreq.DPRRE(i;j).sub.thr, where DPRE(i;j).sub.thr and DPRRE(i;j).sub.