An illustrative embodiment disclosed herein is a method including determining, by a location server, a satellite constellation, a location of a target endpoint, and a next available time of the target endpoint. The method further includes determining, by the location server, a plurality of candidate satellites based on the satellite constellation, the location of the target endpoint, and the next available time of the target endpoint. The method further includes instructing, by the location server, a ground station to broadcast a downlink signal to the plurality of candidate satellites.

An illustrative embodiment disclosed herein is a method, by a satellite, including sending a downlink signal to a first endpoint and a second endpoint at a first time and receiving a first uplink signal from the first endpoint at a second time. The second time is based on a first delay value calculated by the first endpoint. The method further includes receiving a second uplink signal from the second endpoint at a third time. The third time is based on a second delay value calculated by the second endpoint. The method further includes calculating the first delay value and the second delay value based on one or more identifiers of the first endpoint and the second endpoint, respectively, and an algorithm and determining a first distance between the satellite and the first endpoint and a second distance between the satellite and the second endpoint.

In an aspect, a UE may transmit one or more reference signals. The UE may obtain one or more self-radio frequency fingerprint (self-RFFP) measurements based on reflections of the one or more reference signals transmitted by the UE. The UE may determine a location of the UE based on applying a machine learning model to the one or more self-RFFP measurements.

Methods, apparatus, systems and articles of manufacture are disclosed to validate data communicated by a vehicle. An example apparatus an anomaly detector to, in response to data communicated by a vehicle, at least one of compare an estimated speed with a reported speed or compare a location of the vehicle with a reported location. The apparatus including the anomaly detector further to generate an indication of the vehicle in response to the comparison. The apparatus further includes a notifier to discard data sent by the vehicle and notify surrounding vehicles of the data communicated by the vehicle.

First information corresponding to a radio signal received at a first sensing device from a candidate location is obtained. Second information corresponding to a radio signal received at a second sensing device from the candidate location is obtained. A first relationship between the first sensing device and the candidate location and a second relationship between the second sensing device and the candidate location are determined. A first inverse and a second inverse of respectively the first and second relationships are obtained. A first estimate of the radio signal at the first sensing device is determined from the first information and the first inverse. A second estimate of the radio signal at the second sensing device is determined from the second information and the second inverse. Energy emitted from the candidate location is measured based on the first estimate and the second estimate.

System and device configurations, and processes are provided for determining position based on low Earth orbit (LEO) satellite signals. Frameworks described herein can include performing Doppler frequency measurement for received quadrature phase shift keying (QPSK) signals. The framework may include channel tracking operations to determine Doppler shift measurements, a navigation filter operation to determine clock drift based on each Doppler shift measurement from each channel tracking loop, and determining position of a device based on LEO satellite signal sources. Frameworks described herein are also provided for carrier phase differential (CD)low Earth orbit (LEO) (CD-LEO) measurements that may utilize a base and a rover without requiring prior knowledge of rover position. Embodiments can also cancel effects of ionospheric and tropospheric delays on the carrier phase and CD-LEO measurements.

An apparatus, method, and computer program product are provided for communication node localization. For example, a digital fingerprint associated with a communication node in a communication environment is received. The digital fingerprint includes at least location data associated with a location estimate of the communication node and timestamp data associated with one or more measurements with respect to the communication node. Based at least in part on the timestamp data associated with the digital fingerprint, a frequency distribution data structure for the communication node is configured. Additionally, the location data is refined to generate refined location data for the communication node based on a comparison of one or more characteristics between the frequency distribution data structure and respective timetable data structures for respective scheduled events associated with an event location deemed to be at least proximate to the location data.

A method of ranging between a first and a second radio signal transceiver comprises calculating a preliminary estimate of a value proportional to a one-way frequency domain channel response, for a frequency of a plurality of frequencies and for each of a first antenna combination and a second antenna combination of a plurality of antenna combinations; calculating a comparison value for the preliminary estimate, for the frequency and for each of the first antenna combination and the second antenna combination; determining, for the frequency and the first antenna combination, a corrected estimate of the value proportional to the one-way frequency domain channel response based on the preliminary estimate and the comparison value, for the first antenna combination and the second antenna combination; and performing a ranging calculation between the first and the second radio signal transceiver based on a plurality of such corrected estimates.

First information is obtained from a sensing device at a first time. The first information corresponds to a radio signal received at the device from a candidate location. The device is at a first location at the first time. Second information is obtained from the device at a second time. The second information corresponds to a radio signal received at the device from the candidate location. The device is at a second location at the second time. A system determines that a pattern is in each of the first and second information and determines relationships between the candidate location and the device at each first and second location. The system obtains inverses of the relationships and determines estimates of the received radio signals based on the information and inverses. The system measures or estimates energy emitted from the candidate location based on the estimates.

According to an aspect of the invention, there is provided a control system for controlling a projectile, the control system comprising: a plurality of transmitters, wherein each transmitter of the plurality of transmitters is arranged to transmit an electromagnetic wave from a transmission position; a receiver associated with the projectile, the receiver being arranged to receive a plurality of electromagnetic waves transmitted from the plurality of transmitters; a controller associated with the projectile, the controller being arranged to: determine at least one of a position, a velocity or an acceleration of the projectile from transmission positions of the plurality of transmitters and Doppler measurements derived from the received plurality of electromagnetic waves; and generate a control signal for performing an action with the projectile depending on the determined at least one of position, velocity or acceleration of the projectile.