Abstract:
A system and method for determining a set of satellites for which assistance data may be provided to a wireless device. A boundary for an approximate area in which the wireless device is located may be determined and one or more sets of satellites may be determined as a function of the boundary. An optimum set of satellites from the one or more sets of satellites may then be determined using a satellite selection function on the one or more sets of satellites at predetermined points substantially on the boundary.
Abstract:
According to a first aspect, the invention relates to a method for controlling the navigation system of a carrier (P) receiving signals from a plurality of transmitters (T1-T3) and capable of measuring a pseudo-distance to each transmitter, wherein the elevation of each of the transmitters (T1-T3) is controlled relative to the horizontal (H) of the carrier (P), and a navigation solution is developed from the pseudo-distances (Pd-a) for which the elevation of the corresponding transmitter is higher than a minimum elevation (Em), characterised in that it comprises carrying out a discrimination of the multiple routes from the pseudo-distances (formula I) measured for the transmitters (T3) having an elevation lower than the minimum elevation (Em), and further retaining, during the development of the navigation solution, the pseudo-distances (Pd-ad) authorised after said discrimination. The invention also relates to a navigation system capable of implementing the method according to the first aspect of the invention.
Abstract:
An advanced multiple-beam GPS receiving system is achieved that is capable of simultaneously tracking multiple GPS satellites independently, detecting multiple interference signals individually, and suppressing directional gain in the antenna pattern of each beam in the interference directions. The GPS receiving system can be used for both planar and non-planar receiving arrays, including arrays that are conformally applied to the surface of a platform such as an aircraft. The GPS receiver combines spatial filtering and acquisition code correlation for enhanced rejection of interfering sources. Enhanced gain in the direction of GPS satellites and the ability to shape the beam patterns to suppress gain in the direction of interfering sources make the GPS receiving system largely insensitive to interfering and jamming signals that plague conventional GPS receivers.
Abstract:
Method and apparatus for location-based triggering in a mobile receiver is described. In one example, a triggering region is designated. Expected pseudorange data is generated within the mobile receiver and pseudoranges to a plurality of satellites are measured. A delta position is computed with respect to a virtual center of the triggering region using satellite trajectory data, the measured pseudoranges, and the expected pseudoranges. The delta position is compared with the radius restriction value, the results of which may be used to trigger an event. In another example, expected pseudorange data is obtained at the mobile receiver. Pseudoranges from the mobile receiver to a plurality of satellites are measured. The measured pseudoranges and expected pseudoranges are compared using a metric to produce delta values. The delta values are compared with a radius restriction value, the results of which may be used to trigger an event.
Abstract:
Methods and apparatuses for removing the effects of cross-correlation on a satellite positioning system's calculation of position are disclosed. The method includes receiving the SPS signals from in view SPS satellites and determining whether a first measurement, corresponding to a first SPS satellite which has been indicated to be a healthy satellite, is to be removed from a set of measurements to be used to solve for a position of a mobile SPS receiver. Determining includes testing the first measurement is derived from the SPS signals. In one embodiment, the signals from the first SPS satellite may be weaker than the signals from the second SPS satellite, which has been indicated to be an unhealthy satellite.
Abstract:
When two-dimensional determination or three-dimensional determination is not completed within a predetermined time, all satellites being captured are canceled, and the capture processing is resumed with reference to a stored almanac.
Abstract:
A method and an apparatus which acquire satellite positioning system (SPS) signals in an SPS receiver. Information on time of day, approximate receiver location, and satellite positions are used to reduce the time to search and acquire signals from one or more SPS satellites. In an example of a method of the invention, a first pseudorange to a first SPS satellite is determined, and an approximate location of the SPS receiver is determined. An estimated pseudorange for a second pseudorange to a second SPS satellite is determined from the approximate location and a satellite position of the second SPS satellite. The SPS receiver then searches for SPS signals from the second SPS satellite in a range determined by the estimated pseudorange. Typically, this method reduces the search time to initially acquire SPS signals from the second SPS satellite, and the estimated pseudorange is not based on a previously determined pseudorange for said second SPS satellite. In a particular example of the invention, the approximate location is determined from a cell based information source which correlates an identification of each of various wireless cell sites with an approximate location for objects within a cell of a wireless cell based communication system, such as a cellular (or cell based) telephone system. In other examples of the invention, relatively precise time of day information may be used with information indicating satellite positions and information indicating the approximate location to determine an estimated pseudorange for a first SPS satellite to be acquired.
Abstract:
A GPS attitude determining method which is variously applicable to control of the orbit and attitude of satellites, entry of airplanes into the runway, operation of ships, arrangement upon flying, operation of vehicles, etc. When ambiguity integers have been already obtained, there is provided an attitude determination method using a global positioning system (GPS) of determining an attitude using the obtained ambiguity integers and carrier phase measurements. When ambiguity integers are not obtained, there is provided an attitude determination method using the GPS by which the attitude of a navigating body can be easily determined in real time by reducing the amount of calculation required to search for the ambiguity integers using an ambiguity integer search method using a constraint equation. Accordingly, the amount of calculation necessary for searching for the ambiguity integers can be significantly reduced, so that the attitude of a navigating body can be determined in real time. Also, the ambiguity integers are consecutively determined even in the case of insufficient visible satellites and upon blocking of the satellite signal which may occur in real operating circumstances, thus determining the attitude of a navigating body. Furthermore, an accurate attitude of about several mdeg is provided by using the carrier phase measurements.
Abstract:
According to certain embodiments, a method performed by a wireless device comprises receiving Assisted-Global Navigation Satellite System (A-GNSS) information in system information broadcast by a network, receiving signals from a set of GNSS satellites (the set of GNSS satellites comprises at least three GNSS satellites), and determining a location of the wireless device using the A-GNSS information and information received in the signals from the set of GNSS satellites. The method further comprises determining Doppler time and frequency offsets compared to a network satellite. The Doppler time and frequency offsets are determined based on the location of the wireless device. The method further comprises initiating a connection process with the network satellite by transmitting a random access signal with pre-compensated time and frequency, the pre-compensated time and frequency based on the determined Doppler time and frequency offsets.