A receiver authenticates a wideband (WB) signal from global navigation satellites (GNSS) using a narrowband (NB) signal that is also transmitted from the satellites. The NB signal includes segments that are transmitted in time and frequency slots of successive transmission frames. The NB signal is less susceptible to a smart WB jammer. Also, the NB signal segments may also be transmitted at a relative power level with respect to the WB signal, where the relative power level may vary in a known pattern so as to distinguish the WB signal of the satellite from a stronger WB signal from a smart jammer.

A receiver authenticates a wideband (WB) signal from global navigation satellites (GNSS) using a narrowband (NB) signal that is also transmitted from the satellites. The NB signal includes segments that are transmitted in time and frequency slots of successive transmission frames. The NB signal is less susceptible to a smart WB jammer. Also, the NB signal segments may also be transmitted at a relative power level with respect to the WB signal, where the relative power level may vary in a known pattern so as to distinguish the WB signal of the satellite from a stronger WB signal from a smart jammer.

The application discloses a positioning method, device, and system, and a storage medium. The method includes: receiving first location information sent from a terminal, the first location information comprising an identity of the terminal; sending a differential data request to a second server, the differential data request comprising the first location information, and the differential data request being used by the second server to determine differential data of the terminal, receiving the differential data sent from the second server; performing calculation on the first location information according to the differential data to obtain second location information; sending the second location information to the terminal, so that a positioning result can be quickly returned to the terminal, and the network delay is greatly reduced when the terminal determines a precise location.

An authentication system that performs authentication of first location information collected from an apparatus includes an acquisition section configured to acquire one or more pieces of authentication information to be used for the authentication, and an authentication section that determines, using the one or more pieces of authentication information acquired by the acquisition section, whether the first location information is counterfeited, by an authentication method corresponding to each of the one or more pieces of authentication information to authenticate the first location information.

The disclosure provides methods, apparatus, and products for evaluating trustworthiness of GNSS-based location estimates. In one aspect, a method comprises obtaining observation information corresponding to one or more access points observed by a computing device during a time period; obtaining a GNSS-based location estimate indicating an estimated location of the computing device during at least a portion of the time period; determining an access points count corresponding to a number of the one or more observed access points that satisfy a distance criteria relative to the GNSS-based location estimate; comparing the determined access point count to a pre-defined threshold access points count; and based on results of the comparison, providing, by the processor, an indication of whether or not the GNSS-based location estimate is trustworthy. The method may be performed by one or more processors in a cloud-based computing system in response to an API call from the computing device.

The present invention provides a low-cost and low-volume mode A/C/S transponder positioning system to detect the position of a target aircraft, or intruder, outside the range of a secondary surveillance radar system. The system uses a signal of the intruder to pinpoint the location of the intruder. The system can be used on both the ground and on an aircraft in a full 360 degree range around the system.

The present invention provides a low-cost and low-volume mode A/C/S transponder positioning system to detect the position of a target aircraft, or intruder, outside the range of a secondary surveillance radar system. The system uses a signal of the intruder to pinpoint the location of the intruder. The system can be used on both the ground and on an aircraft in a full 360 degree range around the system.

One method comprises receiving a hit signal from a device worn by a first player, receiving a position of the device, receiving an orientation of a launch axis of a virtual-projectile launcher, receiving a position of a second player, and outputting a hit assignment on determining, pursuant to receiving the hit signal, that a recognized object and the second player are coincident at an indicated launch of a virtual projectile. Another method comprises receiving an indication of launch of a virtual projectile by a virtual-projectile launcher of a first player, receiving an image aligned to a launch axis of the virtual-projectile launcher, outputting a hit signal to a server on determining, pursuant to receiving the indication of launch, that a recognized object is imaged in a projectile-delivery area of the image, and outputting a position of the device and an orientation of the launch axis to the server.

One method comprises receiving a hit signal from a device worn by a first player, receiving a position of the device, receiving an orientation of a launch axis of a virtual-projectile launcher, receiving a position of a second player, and outputting a hit assignment on determining, pursuant to receiving the hit signal, that a recognized object and the second player are coincident at an indicated launch of a virtual projectile. Another method comprises receiving an indication of launch of a virtual projectile by a virtual-projectile launcher of a first player, receiving an image aligned to a launch axis of the virtual-projectile launcher, outputting a hit signal to a server on determining, pursuant to receiving the indication of launch, that a recognized object is imaged in a projectile-delivery area of the image, and outputting a position of the device and an orientation of the launch axis to the server.

A radio calibration system includes an FPGA that generates a calibration signal by a pseudo noise generator and mixes the calibration signal with a carrier generated by a carrier generator. The FPGA injects the calibration signal into an analog electronic device which couples the calibration signal into a receiver channel. The receiver channel measures calibration signal power, group delay, and phase, and performs calibration based on these measurements. A reference clock synchronizes the pseudo noise generator, the carrier generator and the receiver channel.