A position-determining apparatus, such as a GPS receiver, determines the position of the mobile device based on the time of flight of a transmitted probe signal using a method in which sections of the received signal is classified into two or more categories and accumulated according to categories before being used to compute the correlations familiar in the context of a matched filter. Using the method of the present invention to compute the correlations, and optionally applying additional time-saving techniques described herein, a position determination is achieved using arithmetic operations that are significantly reduced from that required in prior art methods to compute the correlations. The reduced number of arithmetic operations can reduce significantly the power consumption required of a device carrying out a method of the present invention, and thereby realizing a significant advantage.

According to one aspect of the disclosure, a location node configured to communicate with a wireless device is provided. The location node includes processing circuitry configured to: receive spatial information; determine the wireless device relationship between a first reference station and a second reference station based at least in part on the spatial information; compare a first integer ambiguity level of the first reference station with a second integer ambiguity level of the second reference station, the second reference station corresponding to a current reference station of the wireless device; and transmit an indication of an applicability of the first integer ambiguity level of the first reference station to the second integer ambiguity level of the second reference station for position estimation, the indication being based on the comparison of the first integer ambiguity level with the second integer ambiguity level.

According to one aspect of the disclosure, a location node configured to communicate with a wireless device is provided. The location node includes processing circuitry configured to: receive spatial information; determine the wireless device relationship between a first reference station and a second reference station based at least in part on the spatial information; compare a first integer ambiguity level of the first reference station with a second integer ambiguity level of the second reference station, the second reference station corresponding to a current reference station of the wireless device; and transmit an indication of an applicability of the first integer ambiguity level of the first reference station to the second integer ambiguity level of the second reference station for position estimation, the indication being based on the comparison of the first integer ambiguity level with the second integer ambiguity level.

In accordance with some embodiments, systems, methods, and media for determining a position of an aerial system are provided. In some embodiments, a method comprises: receiving, from a 3D range sensor, position information indicative of a position of one or more objects in a sensor region during a first time period, wherein the position information comprises a plurality of points, each point of the plurality of points being associated with an altitude, and a 2D lateral position; receiving, from the tethered air system, an altitude value; identifying one or more points of the plurality of points with an altitude corresponding to the altitude value; and determining a current position of the tethered air system based on the 2D lateral position associated with the one or more points.

In accordance with some embodiments, systems, methods, and media for determining a position of an aerial system are provided. In some embodiments, a method comprises: receiving, from a 3D range sensor, position information indicative of a position of one or more objects in a sensor region during a first time period, wherein the position information comprises a plurality of points, each point of the plurality of points being associated with an altitude, and a 2D lateral position; receiving, from the tethered air system, an altitude value; identifying one or more points of the plurality of points with an altitude corresponding to the altitude value; and determining a current position of the tethered air system based on the 2D lateral position associated with the one or more points.

Systems and methods for detecting spoofing attempts are disclosed. In one embodiment, a ground station system for detecting a Global Navigation Satellite System (GNSS) spoof signal includes a receiver configured to receive data collected by a detection satellite that (1) is on a first orbit that is lower than a second orbit used by a GNSS satellite and (2) includes: a first antenna positioned to receive signals originating from a planetary surface, and a second antenna positioned to receive signals originating from the GNSS satellite on a higher orbit than the first orbit of the detection satellite. The ground station further includes one or more processors configured to calculate, using the time of arrival of the signal received at the first antenna and the position of the detection satellite determined based on the signal received at the second antenna, a geolocation of a source of the signal originating from a planetary surface.

Systems and methods for detecting spoofing attempts are disclosed. In one embodiment, a ground station system for detecting a Global Navigation Satellite System (GNSS) spoof signal includes a receiver configured to receive data collected by a detection satellite that (1) is on a first orbit that is lower than a second orbit used by a GNSS satellite and (2) includes: a first antenna positioned to receive signals originating from a planetary surface, and a second antenna positioned to receive signals originating from the GNSS satellite on a higher orbit than the first orbit of the detection satellite. The ground station further includes one or more processors configured to calculate, using the time of arrival of the signal received at the first antenna and the position of the detection satellite determined based on the signal received at the second antenna, a geolocation of a source of the signal originating from a planetary surface.

A position detection method to be executed by a computer, the position detection method includes transmitting, by a sensor terminal, a signal obtained by performing capture processing on a satellite signal from a satellite of a search target according to an order of the satellites of the search targets; calculating, by a calculation device, a position of the sensor terminal based on a signal transmitted by the sensor terminal; and determining a satellite having a highest discovery probability based on a specific estimation method for second and subsequent search targets, using an index which is reflected larger as the discovery probability of other satellites is higher or lower, in a case where the first satellite is captured when a first search target is determined.

A position detection method to be executed by a computer, the position detection method includes transmitting, by a sensor terminal, a signal obtained by performing capture processing on a satellite signal from a satellite of a search target according to an order of the satellites of the search targets; calculating, by a calculation device, a position of the sensor terminal based on a signal transmitted by the sensor terminal; and determining a satellite having a highest discovery probability based on a specific estimation method for second and subsequent search targets, using an index which is reflected larger as the discovery probability of other satellites is higher or lower, in a case where the first satellite is captured when a first search target is determined.

An apparatus for matching probe measurements to a path in a geographic location includes a receiver, a window manager, a location generator, a path calculator, and an output. The receiver is configured to receive a stream of probe measurements. The window manager is configured to fill a window with the measurements, to select an additional measurement from the stream, and to select an oldest measurement in the window. The location generator is configured to generate candidate locations for the measurements in the window and the additional measurement. The path calculator is configured to match the oldest measurement to a candidate location. The output is configured to output a path-matched probe measurement based on the oldest measurement and the candidate location matched to the oldest measurement.