Abstract: A method of generating an elevation database for selected geographic regions, the method comprising: receiving a location database, a rule database, and an input elevation database, each location in the location database being located within a selected geographic region; constructing, for each location in the location database and using rules from the rule database, a bounding region enclosing a continuous geographic region; applying elevation data from the input elevation database to each bounding region; and compressing the elevation data in each bounding region to provide compressed elevation data; wherein, upon decompressing the compressed elevation data, each point in each bounding region represents a level of elevation at that point in the associated selected geographic region.

Abstract: A GNSS receiver includes a RF front end for receiving GNSS ranging signals, a navigation processor for calculating location from the ranging signals, and a repository of static data. The navigation processor includes the static data in the location calculation. Examples of static data include a digital elevation map, coordinates of tunnel entrances for use when the receiver resumes reception of the signals upon exiting a tunnel, and descriptions of structures in sufficient detail to enable multipath mitigation.

Abstract: The location of a receiver is determined by receiving respective ranging signals from each of a plurality of transmitters at known locations. The ranging signals are cross-correlated with respective model signals to provide respective cross-correlation functions. For cross correlation functions that are determined to include multipath noise, the multipath noise is estimated and removed. Respective delays of the cross-correlation functions are estimated and the location of the receiver is inferred from the delays.

Abstract: The location of a receiver is determined by receiving respective ranging signals from each of a plurality of transmitters at known locations. The ranging signals are cross-correlated with respective model signals to provide respective cross-correlation functions. For cross correlation functions that are determined to include multipath noise, the multipath noise is estimated and removed. Respective delays of the cross-correlation functions are estimated and the location of the receiver is inferred from the delays.

Abstract: A GNSS receiver includes a RF front end for receiving GNSS ranging signals, a navigation processor for calculating location from the ranging signals, and a repository of static data. The navigation processor includes the static data in the location calculation. Examples of static data include a digital elevation map, coordinates of tunnel entrances for use when the receiver resumes reception of the signals upon exiting a tunnel, and descriptions of structures in sufficient detail to enable multipath mitigation.

Abstract: A method of generating an elevation database for selected geographic regions, the method comprising: receiving a location database, a rule database, and an input elevation database, each location in the location database being located within a selected geographic region; constructing, for each location in the location database and using rules from the rule database, a bounding region enclosing a continuous geographic region; applying elevation data from the input elevation database to each bounding region; and compressing the elevation data in each bounding region to provide compressed elevation data; wherein, upon decompressing the compressed elevation data, each point in each bounding region represents a level of elevation at that point in the associated selected geographic region.

Abstract: A method and system for knowing positioning system standard time at a mobile unit with respect to a system, such as the Global Positioning System, when normal, direct measurement may be impracticable owing to low signal-to noise ratio, by calibrating the timing signal of an available communication network, such as a cellular telephone transmission network (610, 615). A time reference is set for the communication network with respect to the positioning system at a time when an adequate signal-to-noise ratio prevails and the offset of a timing event in the communication network control signal measured by means of the mobile unit's internal clock may be determined (620, 625). Subsequent times are measured with respect to this time reference by using the internal clock to measure time intervals therefrom.

Abstract: A method and system for finding the position of a mobile unit with respect to the satellites of a satellite network such as the Global Positioning System and with respect to the base stations of a wireless communications network. Each satellite transmits a signal that consists of a series of frames of a pseudonoise sequence. The frames of a signal received from the satellite network by the mobile unit are arranged as columns of a matrix and are processed coherently to provide estimated pseudoranges and estimated rates of change of pseudoranges for in view satellites. The coherent processing includes performing an orthogonal transform on the rows of the matrix, multiplying the elements of the matrix by Doppler compensation factors, and then, for each satellite in view, convolving the columns of the matrix with the pseudonoise sequence of that satellite. Other pseudoranges are inferred from synchronization burst sequences received by the mobile unit from one or more base stations.

Abstract: A locator using Navstar constellation signals for determining geographical location of a mobile receiver. The locator is integrated with a mobile unit of a cellular network, which derives its reference frequency from a local oscillator (26). A frequency measuring module (28) counts the number of digital numbers derived from the local oscillator passing between two consecutive time-tagged indicators of the cellular network. The estimated frequency is calculated by dividing the number of digital numbers by the nominal time interval (T0) between the indicators.

Abstract: A disclosed algorithm enables fast and efficient location of a mobile unit by obtaining and processing a snapshot of signals from all satellites in view of a constellation such as the Global Positioning System. The method is capable of dealing with weak signals and requires minimal use of processing time and use of communications resources. Each satellite transmits a signal that consists of a series of frames of a pseudo-noise sequence whereupon is superimposed a satellite data message. The total signal received from the satellite network by the mobile unit is arranged as columns of a matrix and is processed coherently to provide estimated pseudo-ranges and estimated rates of change of pseudo-ranges for in-view satellites. The coherent processing includes performing an initial orthogonal transform on the rows of the matrix and, uses prior knowledge to select that portion of the matrix containing a particular satellite signal for further processing.

Abstract: In a cellular receiver, RF signals of a network are received and front-end processed for extracting baseband signal. A telephony processor (216) consequently extracts telephony signals. When no incoming or outgoing telephony signals are detected, a location processor (220) is set for signal receive, and default settings of a frequency synthesizer (224) of the downconverter is changed. In one embodiment, if no location signal is received, a “power down” routine is implemented.

Abstract: A locator using Navstar constellation signals for determining geographical location of a mobile receiver. The locator is integrated with a mobile unit of a cellular network, which derives its reference frequency from a local oscillator (26). A frequency measuring module (28) counts the number of digital numbers derived from the local oscillator passing between two consecutive time-tagged indicators of the cellular network. The estimated frequency is calculated by dividing the number of digital numbers by the nominal time interval (T0) between the indicators.

Abstract: A method and system for finding the position of a mobile unit with respect to the satellites of a satellite network such as the Global Positioning System and with respect to the base stations of a wireless communications network. Each satellite transmits a signal that consists of a series of frames of a pseudonoise sequence. The frames of a signal received from the satellite network by the mobile unit are arranged as columns of a matrix and are processed coherently to provide estimated pseudoranges and estimated rates of change of pseudoranges for in view satellites. The coherent processing includes performing an orthogonal transform on the rows of the matrix, multiplying the elements of the matrix by Doppler compensation factors, and then, for each satellite in view, convolving the columns of the matrix with the pseudonoise sequence of that satellite. Other pseudoranges are inferred from synchronization burst sequences received by the mobile unit from one or more base stations.