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 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: A method for calibrating a receiver employing integrated location procedures, wherein signals from two radio net-work sources are employed. A system delay (46) is calculated for a first network, and another system delay (46) is calculated for a second network. The differential system delay (50) is stored (53) and used in future location determination sessions. The differential system delay is updated repeatedly, if reception conditions permit.

Abstract: A system for locating a mobile unit (12) of an unsynchronized cellular network, in which a assigned mobile unit (14) is a provisional reference mobile unit (14). The reference mobile unit (14) constantly tries to achieve self location, records base transceiver stations (16 and 18) location times, and synchronize available base transceiver stations (16 and 18) to its own clock, the base transceiver stations (16 and 18) are also synchronized to a system time reference of a navigation satellite system (10). A mobile unit (12) of a cell records reception times of base transceiver stations (16 and 18) and navigation satellites (10), synchronizing them as referenced by local clock. Mobile unit location (12) is processed at central location server or in the mobile unit (12), by collecting reception times, synchronization data from (14) and location parameters if available.

Abstract: A mobile receiver unit (12) of the GPS navigation satellite system is located in accordance with the present invention relative to a reference unit (14) of the same satellite system having known geographic location parameters. Within the frame work of a cell of a cellular network, a plurality of signals of the respective number of radio sources are received by a MU (mobile unit) and by a reference unit. The differences in time of reception of time related structures of the signals are calculated. The difference between the calculated reception time and the measured reception time of each of the respective signals is used to calculate the distance to the radio sources and to the reference unit. Compensation for radio clock drift is performed when required to radio sources by comparing nominal time related structure transmission rate with measured structure transmission rate as referenced by a satellite signal containing a sequence of time related structures.

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: 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.