An exemplary radio-frequency (RF)-based navigation reference system uses one or more non-collocated and time-synchronized direction-finding transmitters to enable a client receiver to estimate its own 3-D position, velocity and time (PVT) using direction-finding (DF) waveforms obtained from said reference transmitters. At least one reference transmitter is sufficient for obtaining a 3-D PVT solution provided the client receiver is equipped with an accurate (low-drift) local clock such as a chip-scale atomic clock (CSAC). All other client receivers require at least two reference transmitters to estimate their 3-D PVT.

Methods and apparatus for determining a location and an orientation of a smart device via wireless communication. The location and direction of the smart device may be used to generate a data query and/or submit information into a data storage, referencing a time, place and direction of the smart device.

Devices, methods, systems, and computer-readable media for calculating a distance and direction from a location tracker to a location of a node are described herein. One or more embodiments include a transmit element to transmit a search command for a first node to one or more nodes, a receive element to receive wireless transmissions from the one or more nodes including range data between the location tracker and each of the one or more nodes, and a time of flight (ToF) ranging calculator to convert the range data to a distance measurement from the location tracker to the first node.

Geolocating an emitter of a low probability of detection (LPD) signal being transmitted from the emitter in an environment with a noise floor, where the LPD signal is below the noise floor. At a sensor node, a version of the LPD signal is received from the emitter. For the version of the LPD signal, cyclostationary feature detection or energy detection of the version of the LPD signal is performed. A low probability of detection descriptor word, including at least one of a frequency feature of the version of the LPD signal or an energy feature of the version of the LPD signal is created. The low probability of detection descriptor word is provided to a data processor, where the data processor is configured to use a plurality of low probability of detection descriptor words from different sensor nodes for different versions of the LPD signal to geolocate the emitter.

Geolocating an emitter of a low probability of detection (LPD) signal being transmitted from the emitter in an environment with a noise floor, where the LPD signal is below the noise floor. At a sensor node, a version of the LPD signal is received from the emitter. For the version of the LPD signal, cyclostationary feature detection or energy detection of the version of the LPD signal is performed. A low probability of detection descriptor word, including at least one of a frequency feature of the version of the LPD signal or an energy feature of the version of the LPD signal is created. The low probability of detection descriptor word is provided to a data processor, where the data processor is configured to use a plurality of low probability of detection descriptor words from different sensor nodes for different versions of the LPD signal to geolocate the emitter.

Innovative new methods in connection with lighter-than-air (LTA) free floating platforms, of facilitating legal transmitter operation, platform flight termination when appropriate, environmentally acceptable landing, and recovery of these devices are provided. The new systems and methods relate to rise rate control, geo-location from a LTA platform including landed payload and ground-based vehicle locations, and steerable recovery systems.

Innovative new methods in connection with lighter-than-air (LTA) free floating platforms, of facilitating legal transmitter operation, platform flight termination when appropriate, environmentally acceptable landing, and recovery of these devices are provided. The new systems and methods relate to rise rate control, geo-location from a LTA platform including landed payload and ground-based vehicle locations, and steerable recovery systems.

In one implementation, a method includes receiving a number of instances of a message that includes a self-reported position of a transmitter of the message from a corresponding number of satellite-based receivers that each received an RF transmission of an instance of the message. The method also includes determining the number of satellite-based receivers that received an instance of the message and selecting a validation technique based on the number of satellite-based receivers that received an instance of the message. If the number of satellite-based receivers that received an instance of the message is one, a propagation-based validation technique is selected. The method further includes determining a measure of the likelihood that the self-reported position of the transmitter is valid using the selected validation technique, and transmitting an indication of the measure of the likelihood that the self-reported position is valid.

In one embodiment, a method is performed. A device may receive an antenna state configuration and a sequence from a wireless access point (AP) device. A plurality of antenna states configured on the device may be selected based on the antenna state configuration and the sequence. An inertial measurement unit (IMU) measurement may be determined. A beacon signal may be transmitted for each selected antenna state. Each transmitted beacon signal may indicate a corresponding selected antenna state.

Provided is a wireless positioning calibration system, including a plurality of transmission base stations, at least one sniffer base station and a positioning server. The at least one sniffer base station receives a plurality of channel state information (CSI) transmitted by the plurality of transmission base stations. The positioning server receives the plurality of CSI transmitted by the at least one sniffer base station. The positioning server calculates a phase error and an antenna spacing error generated by the at least one sniffer base station by means of the plurality of CSI, and compensates the phase error and the antenna spacing error. A wireless positioning calibration method is also provided.