Abstract: 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.

Abstract: An apparatus and method for providing map information of varying resolution to a navigation device. In one embodiment, a position determining system is attached to a navigation device. The position determining system generates position information, such as location, of the navigation device. The position information is transmitted to a base station containing map information. Map information related to, for example, the location of the navigation device is then transmitted from the base station to the navigation device. The map information is displayed on a display of the navigation device. Therefore, the base station only transmits map information related to the position information of the navigation device.

Abstract: A system for tracking the location of, and for providing cellular telephone handoff for, a mobile cellphone user as the cellphone user moves from one cellzone to another. A boundary curve B12 between a first cellzone and an adjacent second cellzone is defined in an electronic map by an equation h.sub.B12 (x,y,z)-K12=0 for points with spatial location coordinates (x,y,z) lying on the curve B12, where K12 is a selected constant. First and second quasi-boundary curves QB1 and QB2, lying within the first and second cellzones, respectively, are defined, where each point on the curve QBi (i=1,2) lies at a selected distance di from the boundary curve B12. A region CR12 of points lying between the quasi-boundary curves QB1 and QB2 and including the boundary curve B12 is defined. The present location of the cellphone user is determined using a Satellite Positioning System (SATPS) such as GPS or GLONASS.

Abstract: Method and apparatus for using a plurality of correlators to improve an estimate of direct signal arrival time by identifying features of a correlation function at and adjacent to the correlation peak. In a first embodiment, the errors in location of the center point of a correlation function R(.tau.), formed by the incoming composite signal and a stored copy of the expected signal, are assumed to be strongly correlated for narrow sample spacing and wide sample spacing of the correlation function. In a second embodiment, multipath signal strengths and phases are estimated, using multiple sampling of the correlation function R(.tau.). This approach assumes that path delays of the direct signal and of the multipath signals can be determined separately.

Abstract: Apparatus and method for providing timing control signals for operation of an engine and other devices on a vehicle and/or operation of telecommunications equipment and/or computer equipment on the vehicle. A Satellite Positioning System (SATPS) antenna and receiver/processor receive and process signals from three or more SATPS satellites and determine and issue SATPS-determined timing pulses and time signals that indicate the time associated with each timing pulse. The pulse-to-pulse time separation .DELTA.t.sub.pp of these timing pulses is adjusted to provide a separation approximately equal to a selected pulse separation .DELTA.t.sub.incr. Alternatively, a supplementary timing device provides a sequence of timing pulses with pulse-to-pulse spacing that is adjustable by varying an environmental parameter .theta., such as temperature or electrical field, for this timing device.

Abstract: A system for selecting an optimal transformation T(G2;G1) between a first ellipsoid E1 (e.g., WGS 84) in a first global coordinate system G1, relative to which the survey measurements are made, and a second ellipsoid E2 in a second global coordinate system G2. A set of location coordinates (x'.sub.m,2, y'.sub.m,2,z'.sub.m,2) for M previously-surveyed locations, numbered m=1, . . . , M, and a set of location coordinates (x'.sub.n,1, y'.sub.n,1,z'.sub.n,1) for N presently-surveyed locations, numbered n=1, . . . , N (M.ltoreq.N) are provided, where the first M presently-surveyed locations coincide with the M previously-surveyed locations. The transformation is chosen so that the images of the location coordinates (x'.sub.n,1,y'.sub.n,1, z'.sub.n,1) for n=1, . . . , M under T(G2;G1) are as close as possible to the corresponding location coordinates (x'.sub.m,2,y'.sub.m,2, z'.sub.m,2) for m=1, . . . , M. Given an ellipsoid and a selected survey plane .tau.

Abstract: Methods for determining the present location coordinates of a user moving in a two-dimensional or three-dimensional space, with reference to an old map that may be inaccurate. Location coordinates (xi',yi') of two or three non-collinear landmarks in two dimensions), or coordinates (xi',yi',zi') of three or four non-coplanar landmarks (in three-dimensions), are indicated on the old map. Corresponding location coordinates (xi,yi) or (xi,yi,zi) are also determined or made available using a location determination system (LDS), such as GPS, GLONASS, Loran, Tacan, Decca, Omega, VOR, DME, JTIDS, PLRS or an FM subcarder system. Location coordinates (xi,yi) (or (xi,yi,zi)) for two or more physical landmarks can be combined into coordinates for a landmark representative. The user's location coordinates (xu,yu) (or (xu,yu,zu)) are also determined or provided using the LDS.

Abstract: Methods for secure communication of location and other information by two spaced apart receivers in a location determination (LD) system, such as GPS, GLONASS and LORAN-C, that use pseudorange corrections to enhance the accuracy of the computed present location of an LD receiver. A pseudorange correction signal PRC(t;i;j), presenting a correction of a pseudorange measurement made at time t at an LD receiver number i from an LD signal issued by an LD signal source number j, is transmitted at a consecutive sequence of times t=t.sub.0, t.sub.1, t.sub.2, . . . , t.sub.n. The pseudorange correction signal PRC(t.sub.n ;i;j), or a message sent in a time interval t.sub.n-1 <t.ltoreq.t.sub.n, is encrypted, using an encryption key that is a function of and depends non-trivially upon one or more of the preceding pseudorange correction values PRC(t.sub.k ;i;j) (k.ltoreq.n-1). This encryption key varies from one time interval t.sub.n-1 <t.ltoreq.t.sub.

Abstract: Apparatus and method for accurately determining the location of an target or other designated object by an observer that is spaced apart from the object. The observer views the target through a viewer and rangefinder and determines the distance of the target from the observer. The observer determines its own location coordinates, and the angular orientation of the rangefinder relative to a selected line or plane, using Satellite Positioning System (SATPS) signals (such as GPS or GLONASS signals) received by three SATPS antennas and processed by a common SATPS receiver/processor. The SATPS receiver/processor then determines the displacement or offset coordinates of the target relative to the observer and displays the target coordinates on the target image seen in the viewer. The target location coordinates and/or the visual image of the target seen in the viewfinder are transmitted to a control station for subsequent use.

Abstract: Method and apparatus for monitoring present location of a site arrestee confined to a permitted site of arbitrary size. Present location of the arrestee can be checked at selected time intervals of several hundred milliseconds to thousands of seconds, as desired. The arrestee wears a location-determining ("LD") unit that receives electromagnetic signals that contain information allowing determination of the present location of the LD unit and arrestee, from three or more non-collinear signal sources. These sources may be radiowave subcarrier transmitters, or may be a combination of radiowave subcarrier transmitters and (1) transmitters for a Loran, Omega, Decca, Tacan, JTIDS Relnav or PLRS or similar ground-based system, or (2) transmitters for a satellite-based positioning system, such as GPS or GLONASS. Present location or change in present location of the LD unit is determined and compared with the permitted site boundary at selected times to determine if the arrestee is present at the site.

Abstract: Method and apparatus for monitoring the present location of an emergency or general serviceperson, such as a firefighter or a hazardous materials spill clean-up specialist, assigned to perform emergency services at a designated site. The site diameter can be as small as a few meters or as large as several kilometers. The serviceperson's present location can be checked at selected time intervals with time periods ranging from a few hundred milliseconds to thousands of seconds, as desired. The serviceperson wears or carries a location-determining ("LD") unit that receives electromagnetic signals that contain information allowing determination of the present location of the LD unit, and thus of the serviceperson, from three or more signal sources.

Abstract: A method for transmitting and verifying the accuracy of a software program, expressed as a stream of J bits.. A first forward error correction error coding, detection and correction (ECDC) procedure is applied to the program, where the first ECDC procedure is expressible as a stream of K1 error coding bits plus L1 additional bits representing the procedure for determining the values of the K1 bits and for detecting the presence of and correcting an error in the original stream of J bits plus the K1 error coding bits, as received by a recipient. A second ECDC procedure is then applied to the K1+L1 bits used in the first ECDC program, where the second ECDC procedure is expressible as a stream of K2 error coding bits plus L2 additional bits representing the procedure for determining the values of the K2 bits and for detecting the presence of and correcting an error in the (K1+L1}bits that represent the first ECDC procedure.

Abstract: Method and apparatus for calibration of sensors and transducers that (a) takes account of the fact that the output variable value may behave differently as a function of the input variable value in different regions of the input variable value and (b) takes account of variation of the output variable value with changes in a plurality of supplemental variables, for a fixed value of the input variable. A discrete set of reference values of each supplemental variable is chosen, and the representation of output variable value as a function of input variable value is determined for each of the set of reference values of the supplemental variables. The representation is then extended to arbitrary values of the supplemental variables by linear or quadratic interpolation.

Abstract: Two methods for determination of thickness of a film of known material that is mounted on one face of a solid substrate of known material are disclosed, using: (1) inversion of an optical beam reflectivity equation; or (2) determination of the film thickness that minimizes the variance of the optical beam reflectivity, computed at each of a predetermined sequence of optical beam wavelengths. Four methods for determination of the (real) refractive index of a film of known thickness mounted on a face of a solid substrate of known material are disclosed, using: (1) minimization of absolute differences of computed and measured optical beam reflectivity, summed over a sequence of known film thicknesses, for assumed values of the refractive index; (2 and 3) two iterative techniques of promote convergence of an estimate of the index to a final value of the refractive index; or (4) solution of a quadratic equation whose coefficients are slowly varying functions of the solution variable.

Abstract: Several methods for evaluating certain changes induced in a film of semiconductor resist material after the coat process and before or at completion of the softbake process, by monitoring thickness of and absorption by a film of resist material.

Abstract: Two methods of determination of the chemical changes induced in a film of material such as photoresist that has been exposed to electromagnetic radiation. Two methods use measurement of polarized light reflected by the film mounted on a substrate to determine a real refractive index or a complex refractive index of the film. Two other methods use measurement of polarized light by the film mounted on a (partly) transparent substrate to determine a real refractive index or a complex refractive index of the film.

Abstract: Method and apparatus for generating two distinct laser frequencies in an optical cavity, using a "T" configuration laser cavity and means for intermittently increasing or decreasing the index of refraction n of an associated transmission medium in one arm of the optical cavity to enhance laser action in one arm or the second arm of the cavity.

Abstract: Apparatus and method for producing a sequence of radiation pulses with a pulse envelope of time variation which is controllable by an external electromagnetic signal applied to an active medium or by a sectored reflector, through which the radiation passes.