Abstract: A system and method for detecting cyber-attacks. The method includes receiving satellite data from at least one satellite orbiting at a location of a ground-level sensor. The satellite data is received from the ground-level sensor. The method also includes determining whether the received satellite data is valid, and upon determining that the received satellite data is invalid, extracting a list of GNSS devices in a region where the ground-level sensor is deployed, and alerting each GNSS device in the list of GNSS devices on a potential cyber-attack.

Abstract: A method for applying GPS UAV attitude estimation to accelerate computer vision. The UAV has a plurality of GPS receivers mounted at fixed locations on the UAV. The method includes receiving GPS signals from each GPS satellite in view of the UAV, the GPS measurements comprising pseudo-range and carrier phase data representing the distance between each GPS receiver and each GPS satellite. Carrier phase and pseudo-range measurements are determined for each GPS receiver based on the pseudo-range and carrier phase data. The GPS carrier phase and pseudo-range measurements are compared pair-wise for each pair of GPS receiver and satellite. An attitude of the UAV is determined based on the relative distance measurements. A 3D camera pose rotation matrix is determined based on the attitude of the UAV. Computer vision image search computations are performed for analyzing the image data received from the UAV in real time using the 3D camera pose rotation matrix.

Abstract: A method includes outputting a plurality of simulated global navigation satellite system (GNSS) and interference signal pairs comprising a simulated GNSS signal and a simulated interference signal. Each of the simulated GNSS signals, or the simulated interference signals, has an associated reference signal. A calibration GNSS signal that combines the simulated GNSS signals and the associated reference signals, or a calibration interference signal that combines the simulated interference signals and the associated reference signals is received. A phase, time, or a power offset is calculated for the simulated GNSS signals based on the calibration GNSS signal and the associated reference signals, or for the simulated interference signals based on the calibration interference signal and the associated reference signals.

Abstract: An embodiment method comprises receiving a satellite signal in a tracking channel, generating a set of replicas of a pseudo random noise sequence, comprising a punctual replica and a plurality of replicas that are different in time with respect to the punctual replica over a given time spacing, correlating the received signal with each replica to obtain amplitude correlation values, monitoring the tracking channel to detect a spoofed signal by generating a further plurality of replicas of the pseudo random noise sequence having a respective time spacing greater than the given time spacing, correlating the received signal of the tracking channel with each further replica to obtain further amplitude correlation values, calculating a shape anomaly factor based on the further correlation amplitude values, verifying the shape anomaly factor is greater than a given shape anomaly threshold, and signaling detection of a spoofed signal on the tracking channel.

Abstract: A method is provided for acquiring a signal from a satellite in a global navigation satellite system. The signal includes a pseudorandom code. The method includes, for each time period of a plurality of time periods: generating samples of the signal, segments of the samples of the signal are correlated with a local copy of the pseudorandom code, thereby producing correlation values for the time period. A discrete Fourier transform is performed using, as inputs, the correlation values for the respective time period, thereby producing a frequency representation of the correlation values for the time period. The frequency representations of the correlation values for the plurality of time periods are combined according to a data hypothesis. When a magnitude of the combined frequency representations meets predefined criteria, a frequency corresponding to the magnitude is selected as a tracking frequency for the satellite.

Abstract: A method for reduced-outlier satellite positioning includes receiving a set of satellite positioning observations at a receiver; generating a first receiver position estimate; generating a set of posterior observation residual values from the set of satellite positioning observations and the first receiver position estimate; based on the set of posterior observation residual values, identifying a subset of the satellite positioning observations as statistical outliers; and after mitigating an effect of the statistical outliers, generating a second receiver position estimate having higher accuracy than the first receiver position estimate.

Abstract: A method of receiving two chip-by-chip multiplexed CSK signals (e.g., GNSS signals) and searching for a non-CSK signal with optimal performance at a given digit capacity of a sampling memory resided in parallel correlators. For CSK signals Prompt, Early and Late results for each of possible code shift are calculated as different sums of four punctured convolutions. Depending on configuration, the method allows to receive both multiplexed CSK signals with lesser quality or one of the CSK signals with better quality. The method can be implemented as an apparatus with four punctured correlators, a set of multipliers by 1 or 2N, another set of multipliers by 1 or 0, summers of four input to one result, a RAM, searchers of maximum, and conditional commutators.

Abstract: Global navigation satellite system (GNSS) radio frequency signals broadcast from geo-stationary satellites 20,000 km above the earth when received by GNSS receivers are fundamentally weak. Accordingly, these GNSS receivers are vulnerable to accidental and deliberate interference from a range of synthetic sources as well as natural sources. Existing anti jamming technologies such as controlled reception pattern antennas, adaptive antennas, null-steering antennas, and beamforming antennas etc. are expensive and incompatible with many lower cost and footprint limited applications. However, in many applications the GNSS antenna is mounted upon a fixed or mobile element such that accidental and intentional jammers tend to be in the plane of the antenna or below it. Accordingly, there are presented designs and techniques to improve the anti-jamming or interference performance of GNSS receivers by further reducing the responsivity of the GNSS receiver to signals in-plane or below the plane of the antenna.

Abstract: A duplicate peak detector acquires and tracks a first correlation peak for a data sequence associated with a navigation satellite in a satellite navigation signal. During tracking of the first correlation peak, a second correlation peak is acquired and tracked for the same data sequence. Respective values of at least one tracking variable of the two correlation peaks are analyzed, and based on the analysis it is determined whether the first and second correlation peaks are associated with the same navigation signal or different navigation signals. If the first correlation peak and the second correlation peak are associated with the same navigation signal, tracking of one of the correlation peaks is discontinued.

Abstract: Disclosed is a beacon-based positioning system. A beacon position in which a beacon is installable is defined in a target space, and a path loss model of radio frequency (RF) signals between all beacon positions and all observation positions of a scanner is determined. Among all possible installation plans for the beacon positions, an installation plan in which different beacon signals, whose RSSIs calculated using the path loss model have significant values, are received in a number greater than or equal to a minimum reference number and a total number of the beacons installed is minimum is determined as an optimal installation plan. The optimization problem of determining the optimal installation plan may be expressed by binary linear programming.

Abstract: A first positioning portion, a calculator, and a second positioning portion are provided in an electronic device targeted for positioning. The first positioning portion obtains, by Doppler positioning, a candidate position which is a candidate for an initial position of the electronic device in code phase positioning from radio waves received from each of GPS satellites. The calculator calculates an index value indicating the magnitude of variation in code phase from a difference between a code phase obtained from the radio waves received from each of the GPS satellites and a code phase obtained based on a candidate position and a position of each GPS satellite. The second positioning portion performs the code phase positioning using ZCount or a candidate position according to the index value.

Abstract: There is provided mechanisms for estimating angle of arrival of a radio signal in a radio communications network. A method is performed by a receiving radio transceiver device. The method comprises obtaining measurements of the radio signal as received in two receive beams covering a given angular sector. The two receive beams are created by analog beamforming in an antenna array. The receive beams have different complex beam patterns and at any angle within the given angular sector at most one of the complex beam patterns has gain below a threshold. The method comprises estimating the angle of arrival of the radio signal by comparing a complex amplitude of the measurements in the two receive beams to a discriminator function.

Abstract: A method for multibeam coverage of a region of the surface of the Earth includes the generation, by a telecommunications payload embedded on a satellite, of a plurality of radiofrequency beams, called elementary beams; the formation of a plurality of radiofrequency beams, called composite beams, exhibiting footprints on the ground of different sizes, each the composite beam being obtained by the grouping of one or more elementary beams; and the transmission or the reception of data through the composite beams, identical data being transmitted or received through all the elementary beams forming one and the same composite beam.

Abstract: An electronically steerable parasitic array radiator (ESPAR) antenna system that includes an ESPAR antenna, a GPS receiver, a GPS low-noise amplifier, a power detector module, and a central processing unit. The GPS receiver is connected to the ESPAR antenna as a separate component. The GPS low-noise amplifier strengthens a signal to propagate through the transmission line and operates in the L1 and L2 GPS bands. The power detector module provides additional amplification for noise quantification. The power detector receives an RF power level and converts the RF power level into a DC voltage output. The central processing unit includes memory that is capable of storing the DC voltage output from the power detector.

Abstract: An apparatus and a method for reducing collision risks between an entity and at least an obstacle, wherein the apparatus includes a transmitter adapted to emit a first beacon signal apt to avoid a collision, a receiver adapted to receive at least a second beacon signal that can be emitted by another apparatus which could dangerously approach to the apparatus, a processor configured for detecting at least the second beacon signal received through the receiver, detecting at least a property of at least the second beacon signal, determining, on the basis of the at least one property of the second beacon signal, at least a property of the first beacon signal, and emitting the first beacon signal through the transmitter in order to reduce collision risks.

Abstract: A plurality of reception modules (1a,1b) receive signals from a plurality of antennas (2a,2b) respectively. A synthesizer (3) synthesizes output signals of the plurality of reception modules (1a,1b). Each of the plurality of reception modules (1a, 1b) includes a first sample-and-hold circuit (7a,7b) sampling and holding a received signal, a second sample-and-hold circuit (8a,8b) sampling and holding an output signal of the first sample-and-hold circuit (7a,7b), and a controller (9a,9b) controlling a timing at which the first sample-and-hold circuit (7a,7b) samples and holds the signal. Operation timings of the first sample-and-hold circuits (7a,7b) are set for the respective reception modules (1a,1b). Operation timings of the second sample-and-hold circuits (8a,8b) of the plurality of reception modules (1a,1b) are same.

Abstract: Systems and methods of heading determination with global navigation satellite system (GNSS) signal measurements are provided herein. A pair of antennas may be separated by a known baseline length and mounted on a vehicle. A GNSS receiver may obtain pseudorange and carrier phase measurements for GNSS satellites within view. An LRU may estimate carrier phase ambiguities and a two-dimensional vector, using the known baseline length and a linearized measurement model. The LRU may determine integer ambiguities using the estimated carrier phase ambiguities. The LRU may determine assumed wrong fixes of the integer ambiguities and a probability of almost fixed value. The LRU may store the set of integer ambiguities. The LRU may determine, from accumulated data over measurement epochs, updated integer ambiguities. The LRU may correct the carrier phase measurements using the updated integer ambiguities. The LRU may compute the heading using the corrected carrier phase measurements.

Abstract: A method for multibeam coverage of a region of the surface of the Earth includes the generation, by a telecommunications payload embedded on a satellite, of a plurality of radiofrequency beams, called elementary beams; the formation of a plurality of radiofrequency beams, called composite beams, exhibiting footprints on the ground of different sizes, each the composite beam being obtained by the grouping of one or more elementary beams; and the transmission or the reception of data through the composite beams, identical data being transmitted or received through all the elementary beams forming one and the same composite beam.

Abstract: A method of inferring the GPS location of a device with a GPS receiver is disclosed. The method includes using signals from two GPS satellites to determine two candidate GPS locations. Geographic information can be used to estimate the probability that the device is at each location. If one of the two candidate GPS locations has a substantially higher probability of being the correct location, that location may be selected as the inferred GPS location. The method may also include making use of additional sensed data that could be provided using sensors onboard the device.

Abstract: A system is disclosed for determining a physical metric such as position. The system comprises a local signal generator (8) configured to provide a local signal and a receiver (4) configured to receive a signal having properties corresponding to those in a signal transmitted by a trusted remote source. An inertial measurement unit (12) is configured to provide a measured or assumed movement of the receiver. A correlator (6) is configured to provide a correlation signal by correlating the local signal with the received signal. A motion compensation unit (14) is configured to provide motion compensation of at least one of the local signal, the received signal, and the correlation signal based on the measured or assumed movement.