摘要:
The present invention provides a scanning ophthalmoscope for scanning the retina of an eye and a method of scanning the retina of an eye. The ophthalmoscope (10) comprises a source of collimated light (12), a first scanning element (14), a second scanning element (16) and a scan relay device (18) having two foci (18a, 18b). The source of collimated light (12), the first and second scanning elements (14, 16) and the scan relay device (18) combine to provide a two-dimensional collimated light scan (21) from an apparent point source (19). The scanning ophthalmoscope (10) further comprises a scan transfer device (20), wherein the scan transfer device (20) has two foci (20a, 20b) and at least one vertex (20c) and the apparent point source (19) is provided at a first focus (20a) of the scan transfer device (20) and an eye (22) is accommodated at a second focus (20b) of the scan transfer device (20), and wherein the scan transfer device (20) transfers the two-dimensional collimated light scan (21) from the apparent point source (19) into the eye (22). The two foci (18a, 18b) of the scan relay device (18) and the two foci (20a, 20b) of the scan transfer device (20) define a first plane and the two foci (20a, 20b) and the at least one vertex (20c) of the scan transfer device (20) define a second plane and wherein the first and second planes are substantially parallel.
摘要:
A system and method for determining the location of a wireless device. A boundary for an approximate area in which the wireless device is located is determined and a plurality of satellites may be determined as a function of the boundary. Assistance data is transmitted to the device which includes information from the plurality of satellites, and the location of the wireless device may be determined from the information. In one embodiment, if the number of the plurality of satellites is greater than a predetermined threshold then the number of satellites may be reduced as a function of one or more of the elevation of each satellite above the horizon, a distance between each satellite to one or more other satellites, and an altitude of each satellite.
摘要:
A disclosed method uses the results of location queries to tune the value of measurements of a property to obtain a statistically representative measurement for geo location. As location requests arrive, a current measurement value associated with the serving area or location is used to determine the number of measurements to obtained; the resulting uncertainty is mapped against the number of measurements required to determine that value. If additional measurements are required to achieve the target uncertainty in the result, this is recorded. The process relies on empirical observations and has the additional advantage of being blind to the actual network topology. This approach by its own nature automatically takes into account network changes whether known or unknown.
摘要:
A system and method for determining whether a wireless device has transmitted one or more forged satellite measurements. An estimated location of the wireless device may be determined as a function of information from a cellular network. Acquisition assistance data may be determined for a first set of satellites as a function of the estimated location, the assistance data including an uncertainty window. If measured code phase information in the satellite measurements substantially correlates to the uncertainty window, then the wireless device may be transmitting forged satellite measurements.
摘要:
A system and method for estimating the position of a mobile device using information from a constellation of satellites. A first set of satellites of the constellation may be selected and then a second set of satellites of the constellation may be selected as a function of signals received from the first set of satellites. Data may be transmitted to the mobile device based on signals received from the second set of satellites, and a location of the device estimated based on the data. One embodiment may select the second set as a function of an intersection of coverage areas of ones of the first set of satellites. Another embodiment may select the second set as a function of one or more satellites that are not occluded by the Earth from one or more of the first set of satellites.
摘要:
An extension to the Location Information Service (LIS) architecture uses a centralized, user-selected, Privacy Profile Register (PPR) and Presence Register (PR) element, the User Privacy and Presence Register (UPPR) (also known as the Home Register (HR)). This centralized model provides access to value added services that allow the user to be located anywhere in the world by people and services of his choosing. It also provides network elements using this location information with security that the location being provided has certification.
摘要:
A system and method for estimating the position of a mobile device using information from a constellation of satellites. A first set of satellites of the constellation may be selected and then a second set of satellites of the constellation may be selected as a function of signals received from the first set of satellites. Data may be transmitted to the mobile device based on signals received from the second set of satellites, and a location of the device estimated based on the data. One embodiment may select the second set as a function of an intersection of coverage areas of ones of the first set of satellites. Another embodiment may select the second set as a function of one or more satellites that are not occluded by the Earth from one or more of the first set of satellites.
摘要:
A system and method for determining whether an estimated location of a wireless device includes one or more forged satellite measurements. An estimated location of the wireless device may be determined from signals received from a first set of satellites, and a set of residuals obtained as a function of the estimated location. The obtained set of residuals may then be compared to a reference set of residuals. If the comparison between the obtained set and reference set of residuals is less than a predetermined threshold, then the estimated location may be identified as having one or more forged satellite measurements.
摘要:
A system and method for determining the location of a wireless device. A boundary for an approximate area in which the wireless device is located is determined and a plurality of satellites may be determined as a function of the boundary. Assistance data is transmitted to the device which includes information from the plurality of satellites, and the location of the wireless device may be determined from the information. In one embodiment, if the number of the plurality of satellites is greater than a predetermined threshold then the number of satellites may be reduced as a function of one or more of the elevation of each satellite above the horizon, a distance between each satellite to one or more other satellites, and an altitude of each satellite.
摘要:
An extension to the Location Information Service (LIS) architecture uses a centralized, user-selected, Privacy Profile Register (PPR) and Presence Register (PR) element, the User Privacy and Presence Register (UPPR) (also known as the Home Register (HR)). This centralized model provides access to value added services that allow the user to be located anywhere in the world by people and services of his choosing. It also provides network elements using this location information with security that the location being provided has certification.