Abstract: A wireless communication device includes: a plurality of subarrays each including a plurality of antenna elements and an analog circuit configured to perform a given analog process on signals to be transmitted from or received by the antenna elements; and a processor that is connected to the subarrays. The processor executes a process including: estimating direction of arrivals from which signals transmitted from a plurality of terminals come; calculating maps based on trigonometric functions of angles representing the estimated direction of arrivals; generating a plurality of groups to which the terminals belong based on the calculated maps; assigning, to each of the groups, a combination of subarrays to generate directional beams that do not interfere with each other; and determining weighting coefficients to generate directional beams in directions of the terminals which belongs to each group by using the combination of subarrays assigned.

Abstract: The invention relates to a method carried out by a navigation satellite system (NSS) receiver or a processing entity receiving data therefrom, for estimating parameters useful to determine a position. The NSS receiver observes NSS signals from NSS satellites. Two filters, called “robustifier” and “main estimator” respectively, both use state variables and compute the values thereof based on: NSS signals observed by the NSS receiver, and/or information derived therefrom. The robustifier identifies, within the input data, measurements that do not match a stochastic model assigned thereto. For each identified measurement, the robustifier rejects the measurement, adjusts the stochastic model assigned to the measurement, and/or corrects the measurement. The robustifier uses fewer state variables than the main estimator. A corresponding system is also disclosed.

Abstract: The present invention discloses a cubature Kalman filtering method suitable for high-dimensional GNSS/INS deep coupling, including: S1, constructing a high-dimensional GNSS/INS deep coupling filter model; S2, generating an initialization cubature point for the constructed filter model by using standard cubature rules; S3, performing CKF filtering by using novel cubature point update rules. The present invention is suitable for high-dimensional GNSS/INS deep coupling filtering with high precision and high stability.

Abstract: A photoconductive antenna has an array of antenna electrodes on or in a photoconductive substrate. The photoconductive substrate is irradiated with light from a pulsed laser via micro-lenses above respective gaps between antenna electrodes. This makes the photoconductive substrate temporarily conductive, causing pulsed electric antenna currents that can be used for transmission of electromagnetic radiation in the Terahertz range. The bias circuit of the antenna is configured to determine voltages applied to the antenna electrodes by capacitive voltage division over a series of successive capacitors, each capacitor being formed by the antenna electrodes of a respective pair of successive ones of the antenna electrodes in the array as plates of the capacitor adjacent to a respective one of the gaps.

Abstract: Beacon-based Precision Navigation and Timing (PNT) may use a constellation of space vehicles (e.g., small, low cost satellites) coupled to a network of ground stations and a network of beacons. Such a system be provided at a cost that is approximately 100 times lower than GPS both to build and to operate. The resulting system may also provide fast acquisition, improved SNR, improved anti-jam and anti-spoofing capabilities, and six-inch scale location determination, making it applicable to both existing PNT applications and enabling new applications.

Abstract: A method and apparatus is disclosed herein for acquiring and tracking a satellite signal with an antenna. In one embodiment, the method comprises a) perturbing one or more of roll, pitch and yaw angles of an antenna orientation to create variant orientations associated with a first search pattern; b) computing new scan and polarization angles, in response to perturbed roll, pitch and yaw angles, for each of the variant orientations; c) receiving a radio-frequency (RF) signal from a satellite for each of the variant orientations; d) generating one or more receiver metrics representing a received RF signal associated with each of the variant orientations; e) selecting, as a new orientation, one of the variant orientations based on the one or more receiver metrics; and f) repeating a)-e) with the new orientation with a second search pattern narrower than the first search pattern.

Abstract: An apparatus and method of delivering an alert from an aircraft to a search and rescue system. An alert from an aircraft is received via a communications satellite. The alert comprises identification information identifying the aircraft and position information identifying the position of the aircraft. In response to receiving the alert, an emulated distress radio beacon signal is generated. The emulated distress radio beacon signal comprises the identification information and the position information in a standard format of a signal generated by a distress radio beacon. The emulated distress radio beacon signal is broadcast from a location other than the aircraft as an emulated distress radio beacon transmission that is configured to be received and processed by the search and rescue system.

Abstract: Techniques provided herein are directed toward virtually extending an updated set of output positions of a mobile device determined by a VIO by combining a current set of VIO output positions with one or more previous sets of VIO output positions in such a way that ensure all outputs positions among the various combined sets of output positions are consistent. The combined sets can be used for accurate position determination of the mobile device. Moreover, the position determination further may be based on GNSS measurements.

Abstract: A method for each of a plurality of satellites of a secondary Global Navigation Satellite System, GNSS, in a Low Earth Orbit, LEO, comprising receiving GNSS signals, in a first frequency band, from Line-Of-Sight, LOS, satellites of at least one primary GNSS in a Medium Earth Orbit. Candidate sets of orbit and clock corrections for the LOS satellites are received. A Position-Velocity-Time, PVT, calculation is performed based on code and/or carrier pseudo-ranges between a respective satellite of the secondary GNSS and the LOS satellites. The code and/or carrier pseudo-ranges are derived from the GNSS signals and are corrected by a single set of the candidate sets. A short-term prediction model is determined for an orbit and clock of the respective satellite based on the PVT and is included in a navigation message, transmitted in a second frequency band, modulated onto a LEO navigation signal intended for terrestrial user equipment.

Abstract: A multi-band satellite navigation receiver for carrier and code tracking using a fixed point sigma rho filter with improved stability is described. The receiver simplifies and speeds up the data processing in the filter to adaptively accommodate common information from aggregate bands and obtain the accurate position of the receiver in real time. The filter may utilize a standard deviation function and a cross correlation function while determining adaptive scale factors to ensure that the filter is stable and reliable.

Abstract: A method of determining geographic positions of a head of train (HOT) unit and an end of train (EOT) unit of a train includes receiving, by the HOT, first satellite radio position data and position correction data; determining, by the HOT, a first geographic location of the HOT based on the first satellite radio position data and the position correction data received by the HOT; receiving, by the EOT, second satellite radio position data; receiving, by the EOT from the HOT via a communication link, a copy of the position correction data received by the HOT; determining, by the EOT, a second geographic location of the EOT based on the second satellite radio position data and the position correction data received by the EOT; and receiving, by the HOT from the EOT, a copy of second geographic location of the EOT.

Abstract: The invention relates to a method for locating at least two sources emitting electromagnetic pulses in an environment comprising two reflectors. The method comprises receiving, by a detector, for each source to be located, at least one same emitted pulse, received directly from said source and received by reflection on one of the reflectors. The method further comprises: identification of the pulses received directly and the pulses received by reflection, grouping by pairs of pulses received directly with pulses received by reflection, calculating, for each pair, the difference between the date of arrival of the pulse received by reflection relative to the date of arrival of the pulse received directly, and determining the distance of each source from the detector from calculated differences in dates of arrival.

Abstract: A position fix identifying a geographic location of a receiver is received. The position fix was generated using signals received at the receiver from respective high-altitude signal sources (such as satellites). Imagery of a geographic area that includes the geographic location is also received. The imagery is automatically processed to determine whether one or more of the high-altitude signal sources were occluded from the geographic location when the position fix was generated. In response to determining that one or more of the high-altitude signal sources were occluded from the geographic location when the position fix was generated, the position fix is identified as being potentially erroneous.

Abstract: A method and system for broadcasting a beacon identifier identifying the beacon system from the beacon system to a user device, receiving the beacon identifier at a content determination system from the user device, determining contextual content at the content determination system based on the beacon identifier, transmitting the contextual content from the content determination system to the user device, where the user device automatically transmits the contextual content to the first beacon system in response to receiving the contextual content, receiving the contextual content at the beacon system from the user device, and controlling the output display with the beacon system to present the contextual content.

Abstract: A device and method for detecting presence of a wireless communication device having an antenna with intrinsic characteristics includes a transmitter, a receiver, a memory element, and a processing element. The transmitter may send a first signal to the antenna of the wireless communication device. The receiver may receive a second signal from the antenna of the wireless communication device, the second signal being a first portion of the first signal that is reflected by the antenna based on intrinsic characteristics of the antenna. The memory element may store intrinsic characteristic information for the antenna. The processing element may determine presence of the wireless communication device by analyzing the second signal against the intrinsic characteristic information stored in the memory element.

Abstract: Systems and methods described herein are directed towards a radar system and a dual frequency electronically scanned array (ESA) capable of transmitting and receiving radio frequency (RF) signals at least two frequencies. The ESA includes a plurality of antenna elements which form a first effective aperture at a first radio frequency (RF) frequency and operational over a first scan range and which form a second effective aperture at a second radio frequency (RF) frequency and operational over a second scan angle. The first and second scan ranges are complementary so as to provide the radar system having an overall scan range. The plurality of antenna elements are spaced apart from each other by an amount related to at least one of the first and second scan ranges and/or one or more operating frequencies of the radar system.

Abstract: A method for improving positioning accuracy of global navigation satellite systems includes: in a first step, a reference station located at a base station of a mobile communication network receives at least a first satellite signal transmitted from a global navigation satellite system; in a second step, subsequent to the first step, a server of the mobile communication network calculates correction information based on the first satellite signal received by the reference station; in a third step, subsequent to the second step, the correction information is transmitted to a mobile user equipment entity from a base station of the mobile communication network; in a fourth step, the mobile user equipment entity receives a second satellite signal transmitted from the global navigation satellite system; and in a fifth step, subsequent to the third step, the position of the mobile user equipment entity is calculated based on the correction information and the second satellite signal.

Abstract: A method and a system for detecting cross correlation in a satellite navigation receiver (SNR) in real tune are provided. The SNR parallelly receives navigation signals from multiple satellites via multiple input channels. The SNR extracts ephemeris data from sub-frames of navigation data of each of the navigation signals. The SNR compares the ephemeris data of each navigation signal with the ephemeris data of another navigation signal. The SNR detects cross correlation between the navigation signals when the ephemeris data comparison results in a match and discards the navigation signal with low signal strength. The SNR also retrieves a ranging code from the sub-frames of navigation data of each navigation signal. The SNR compares the ranging code with a pre-programmed satellite identity code of a corresponding satellite. The SNR detects cross correlation when the code comparison results in a mismatch and discards the navigation signal with the mismatched ranging code.

Abstract: The invention relates to a method for selecting a satellite which is designed to send a global navigation satellite system-signal, also known as a GNSS-Signal, to a vehicle, consisting of: measuring measurement position data of the vehicle in relation to the satellite based on the GNSS-Signal; determining redundant reference position data of the vehicle in relation to the measurement position data determined according to the GNSS-Signal; and selecting the satellite when a comparison of the measurement position data and the reference position data meets a predetermined condition.

Abstract: A system and method for inspecting a railway track using sensors oriented at an oblique angle relative to a rail vehicle on which the system is traveling. The orientation of the sensors allows for different data to be gathered regarding a particular rail including rail design specifications (gathered based on manufacturer markings detected and analyzed by the system), rail seat abrasion values based on direct measurement of rails from the oblique angle, and other analysis of rail features including joint bars, rail welds, bond wires, rail holes, and broken rails. The use of an air blower, ducts, and one or more air distribution lids over the sensors helps remove debris from blocking the sensors and structured light generators.