Disclosed are a clock offset determination method and apparatus. The clock offset determination method provided in the embodiment of the present application includes: determining, by measuring downlink positioning reference signals (PRS) from a reference base station and a non-reference base station, a first positioning measurement value; determining, on the basis of the first positioning measurement value, a first clock offset between the reference base station and the non-reference base station; and on the basis of the first clock offset, assisting a target terminal to obtain a second clock offset.

A method of analyzing a ground-based augmentation system (GBAS) signal, comprising: transmitting at least one GBAS message burst; receiving the GBAS message burst, and performing a power measurement at symbol times of the GBAS message burst. Further, a test system for testing a ground-based augmentation system is described.

Systems and methods for inertial navigation aided by signals of opportunity (SOOP). One system includes a network operations center (NOC), a reference station, and mobile user equipment. Another system includes a NOC and user equipment without a reference station. In the latter system, the NOC comprises an antenna, a NOC receiver that generates SOOP data derived from SOOP, a computer system that generates SOOP source location/ephemeris data and inter-source clock bias data based on SOOP data generated by the NOC receiver, and a communication device to broadcast the data. The user equipment comprises an antenna, a navigation receiver that generates SOOP data derived from SOOP detected by the antenna of the user equipment, and a navigation computer system that calculates a navigation solution, including a SOOP-derived estimated position of the user equipment, based on SOOP source location/ephemeris data and inter-source clock bias data broadcasted by the NOC and SOOP data generated by the navigation receiver.

Methods and systems for providing voice, video, or data services using optimized ground track satellites and ground tracking antennas are disclosed herein. An example system includes first satellites in a first constellation, the first set of satellites having a first fixed ground track relative to Earth's surface, and an antenna being located at a location on the first fixed ground track, the antenna being configured to steer in a single axis to track the first satellites, wherein each of the first satellites reach the location, after an integer number of days that include a period of two or more sidereal days with an adjustment to account for nodal precession of the first satellites.

Methods of checking the integrity of the estimation of the position of a mobile carrier are provided, the position being established by a satellite-based positioning measurement system, the estimation being obtained by the so-called real time kinematic procedures. The method verifies that the carrier phase measurement is consistent with the code pseudo-distance measurement. The method comprises a step of calculating the velocity of the carrier, at each observation instant, a step of verifying that at each of the observation instants, the short-term evolution of the carrier phase of the signals received on each of the satellite sight axes is consistent with the calculated velocity and a step of verifying that at each of the observation instants, the filtered position obtained on the basis of the long-term filtered measurements of pseudo-distance through the carrier phase is dependable.

A system and a method are disclosed for enabling seamlessly tracking a location of a water vessel by supplementing satellite data with mobile data location based on proximity of a water vessel to shore. The system receives a Global Positioning System (GPS) location of the water vessel, the GPS location of the water vessel based on using the satellite data of the water vessel. The system determines that the GPS location is within a threshold distance of a boundary. Responsive to determining that the GPS location is within the threshold distance of the boundary, the system initiates monitoring for a mobile signal emanating from a trajectory path of the water vessel. The system detects, during the monitoring, the mobile signal, the tracking the location of the water vessel based on mobile data of the mobile signal. The system provides the tracked location to a monitoring device.

A method for using global positioning system (GPS) repeaters to obfuscate a location of a mobile device operating in an area of a communications network, the communication network including a monitoring system, includes receiving an indication that the mobile device enters the communications network; requesting a GPS location from the mobile device; receiving repeated GPS information from the mobile device; calculating a obfuscated location of the mobile device; mapping the obfuscated location of the mobile device to a table of defined locations to produce an actual mobile device location; and reporting the actual location of the mobile device.

Accurate position capability can be quickly provided using a Wireless Local Area Network (WLAN). When associated with a WLAN, a wireless device can quickly determine its relative and/or coordinate position based on information provided by an access point in the WLAN. Before a wireless device disassociates with the access point, the WLAN can periodically provide time, location, and decoded GPS data to the wireless device. In this manner, the wireless device can significantly reduce the time to acquire the necessary GPS satellite data (i.e. on the order if seconds instead of minutes) to determine its coordinate position.

Interaction with a handheld device is modified based upon the speed at which the handheld device is traveling, for example while being held in a passenger vehicle. If the handheld device appears to be moving faster than a pre-established threshold, a lockout flag indicates that interaction with the user must be modified. Then, the lockout flag is cleared only when the handheld device is held off at an angle and the user focuses gaze upon the display for a minimum amount of time. Once the lockout flag is cleared, interaction with the user returns to a normal state.

Aspects of the disclosure include a method of prioritizing generation of predicted ephemeris data. The method includes receiving, by a device through a data network, first ephemeris seed data of a subset of a plurality of satellites, identifying a first satellite and a second satellite of the plurality of satellites, the first satellite being potentially detectable by the device at an estimated position at a given time, and the second satellite being potentially undetectable by the device at the estimated position at the given time, and prioritizing generation of first predicted ephemeris data that represent a first orbit of the first satellite before generation of second predicted ephemeris data that represent a second orbit of the second satellite. The generation of the first predicted ephemeris is based on the first ephemeris seed data.