Abstract: Approaches for detecting and/or rejecting fraudulent positioning system signals at one or more positioning system receivers. The receivers may establish a time search window that may be maintained beyond a time in which a fraudulent signal is expected to move away from an authentic signal a sufficient amount so as to fall outside the time search window. Various approaches are described for updating the time signal at the receiver to maintain accuracy without acquiescing to the introduced bias of a fraudulent signal. Also, an approach for evaluation of candidate signals for consistency at one or more stationary receivers is described. Also, approaches for collective evaluation of signals provided from networked receivers are described to provide sentry receivers operative to detect and alert the presence of a fraudulent signal.

Abstract: Determination of one or more timing (phase) and/or frequency corrections to be made to a local time base of a receiver device to synchronize the local time base with the time of GPS or other highly accurate time base. Timing packets from one or more grandmaster devices whose time bases are substantially the same as that of GPS or the like and/or positioning system signals (e.g., GPS signals) directly from a positioning system are received and manipulated to determine the timing and/or frequency corrections. The corrected time base may be used to assist in acquiring such positioning signals to allow for higher accuracy correction and/or for downstream communication operation. The present utilities are advantageous such as when a sufficient number of channels (e.g., four) from the receiver device to positioning system satellites are unavailable to synchronize the local time base to the GPS or other accurate time base.

Abstract: There is provided a subject location system, including a master processing unit, a receiver, and at least one Tag associated with the subject. The system includes a Hub with a master processing unit and the Tag includes transponders. Range and phase data are used to calculate the position of the Tag in relation to the Hub, and phase cycle errors are eliminated by, the use of a cyclical search minimizing an innovation inner product.

Abstract: Determination of one or more timing (phase) and/or frequency corrections to be made to a local time base of a receiver device to synchronize the local time base with the time of GPS or other highly accurate time base. Timing packets from one or more grandmaster devices whose time bases are substantially the same as that of GPS or the like and/or positioning system signals (e.g., GPS signals) directly from a positioning system are received and manipulated to determine the timing and/or frequency corrections. The corrected time base may be used to assist in acquiring such positioning signals to allow for higher accuracy correction and/or for downstream communication operation. The present utilities are advantageous such as when a sufficient number of channels (e.g., four) from the receiver device to positioning system satellites are unavailable to synchronize the local time base to the GPS or other accurate time base.

Abstract: Wave based signals such as radio transmissions are susceptible to frequency alterations caused by the relative movement between a transmitter and a receiver. In a satellite context, the radio signals emitted by a satellite based transmitter may take on a frequency higher or lower than the actual frequency at which they are generated depending on whether the satellite is moving toward or away from the receiver, respectively. By calculating the theoretical frequency shift (Doppler shift) that should occur if a signal travels directly from a satellite to a receiver, the actual frequency of the signal as received can be used to determine if the signal's integrity is sufficient or if it has been compromised by some sort of interference or malfunction.

Abstract: Determination of one or more timing (phase) and/or frequency corrections to be made to a local time base of a receiver device to synchronize the local time base with the time of GPS or other highly accurate time base. Timing packets from one or more grandmaster devices whose time bases are substantially the same as that of GPS or the like and/or positioning system signals (e.g., GPS signals) directly from a positioning system are received and manipulated to determine the timing and/or frequency corrections. The corrected time base may be used to assist in acquiring such positioning signals to allow for higher accuracy correction and/or for downstream communication operation. The present utilities are advantageous such as when a sufficient number of channels (e.g., four) from the receiver device to positioning system satellites are unavailable to synchronize the local time base to the GPS or other accurate time base.

Abstract: Approaches for detecting and/or rejecting fraudulent positioning system signals at one or more positioning system receivers. The receivers may establish a time search window that may be maintained beyond a time in which a fraudulent signal is expected to move away from an authentic signal a sufficient amount so as to fall outside the time search window. Various approaches are described for updating the time signal at the receiver to maintain accuracy without acquiescing to the introduced bias of a fraudulent signal. Also, an approach for evaluation of candidate signals for consistency at one or more stationary receivers is described. Also, approaches for collective evaluation of signals provided from networked receivers are described to provide sentry receivers operative to detect and alert the presence of a fraudulent signal.

Abstract: Location of a device within a monitored environment with compromised communication with ranging communication nodes. Specifically, an intermediate device previously located by communication with ranging communication nodes is provided to provide a ranging signal to a device to be located. The device to be located may in turn use a ranging signal received from communication with the previously located device and one or more ranging communication nodes to resolve a location.

Abstract: Positioning, navigation, and timing (“PNT”) signals, such as those used in GNSS or LORAN systems, may be vulnerable to spoofing attacks. To generate trustworthy time and location data at a receiver, one must at least reduce the likelihood of or be capable of detecting spoofing attacks. Embodiments of the present invention, as presented herein, provide solutions for detecting spoofing of PNT signals. Various aspects incorporated into the described embodiments which assist in detecting spoofing attacks may include but are not limited to: monitoring the SNR of received PNT signals of a first modality and switching over to an alternate PNT modality when an anomaly is detected, comparing data associated with signals of multiple PNT modalities to identify a discrepancy indicative of spoofing on one of the multiple PNT modalities, and implementing a security regime to prevent spoofers from being able to produce perceivably authentic, but corrupt, replica signals of a PNT modality.

Abstract: Location of a device within a monitored environment with compromised communication with ranging communication nodes. Specifically, an intermediate device previously located by communication with ranging communication nodes is provided to provide a ranging signal to a device to be located. The device to be located may in turn use a ranging signal received from communication with the previously located device and one or more ranging communication nodes to resolve a location.

Abstract: Determination of a signal loss profile relative to a receiver based on measured signal power of a sounding signal from a sounding transmitter having a known signal power in free space relative to the receiver. The signal loss profile may include a plurality of signal loss values corresponding to a plurality of received sounding signals at the receiver. In an embodiment, the sounding signal may comprise a GNSS navigational signal (e.g., a GPS signal). The signal loss profile may be used to extrapolate signal loss for a transmitter collocated with the receiver. In turn, the signal loss profile may be used in conjunction with a shared spectrum system to model a signal propagation from the collocated transmitter when determining allocation of a shared spectrum resource of the shared spectrum system.

Abstract: The present disclosure is directed to utilities (methods, systems, apparatuses) associated with improving the signal-to-noise ratio of a wireless signal at a receiver. It is known in the art to correlate a received signal with a replica signal generated at the receiver to improve reception. However, the inventors have determined that correlation using a replica signal which is not completely accurate may be detrimental. An improved method of correlation disclosed herein includes identifying data bits which are predictable and performing correlation with respect to those data bits while ignoring data bits which are identified as unpredictable. This method may have particular advantages in the case of receivers having attenuated reception (e.g., indoors) after losing a data connection used for receipt of assistance data.

Abstract: Wave based signals such as radio transmissions are susceptible to frequency alterations caused by the relative movement between a transmitter and a receiver. In a satellite context, the radio signals emitted by a satellite based transmitter may take on a frequency higher or lower than the actual frequency at which they are generated depending on whether the satellite is moving toward or away from the receiver, respectively. By calculating the theoretical frequency shift (Doppler shift) that should occur if a signal travels directly from a satellite to a receiver, the actual frequency of the signal as received can be used to determine if the signal's integrity is sufficient or if it has been compromised by some sort of interference or malfunction.

Abstract: Data bandwidth reduction in positioning system signals. Specifically, a first, relatively easily acquired signal may be analyzed to determine if and/or to what extent to decimate a second signal. The second signal may comprise a higher encoded data rate (e.g., a chip rate). In turn, decimation of the second signal based on characteristics of the first signal may allow for more efficient processing of the second signal.

Abstract: Positioning, navigation, and timing (“PNT”) signals, such as those used in GNSS or LORAN systems, may be vulnerable to spoofing attacks. To generate trustworthy time and location data at a receiver, one must at least reduce the likelihood of or be capable of detecting spoofing attacks. Embodiments of the present invention, as presented herein, provide solutions for detecting spoofing of PNT signals. Various aspects incorporated into the described embodiments which assist in detecting spoofing attacks may include but are not limited to: monitoring the SNR of received PNT signals of a first modality and switching over to an alternate PNT modality when an anomaly is detected, comparing data associated with signals of multiple PNT modalities to identify a discrepancy indicative of spoofing on one of the multiple PNT modalities, and implementing a security regime to prevent spoofers from being able to produce perceivably authentic, but corrupt, replica signals of a PNT modality.

Abstract: Determination of one or more timing (phase) and/or frequency corrections to be made to a local time base of a receiver device to synchronize the local time base with the time of GPS or other highly accurate time base. Timing packets from one or more grandmaster devices whose time bases are substantially the same as that of GPS or the like and/or positioning system signals (e.g., GPS signals) directly from a positioning system are received and manipulated to determine the timing and/or frequency corrections. The corrected time base may be used to assist in acquiring such positioning signals to allow for higher accuracy correction and/or for downstream communication operation. The present utilities are advantageous such as when a sufficient number of channels (e.g., four) from the receiver device to positioning system satellites are unavailable to synchronize the local time base to the GPS or other accurate time base.

Abstract: The present disclosure is directed to utilities (methods, systems, apparatuses) associated with improving the signal-to-noise ratio of a wireless signal at a receiver. It is known in the art to correlate a received signal with a replica signal generated at the receiver to improve reception. However, the inventors have determined that correlation using a replica signal which is not completely accurate may be detrimental. An improved method of correlation disclosed herein includes identifying data bits which are predictable and performing correlation with respect to those data bits while ignoring data bits which are identified as unpredictable. This method may have particular advantages in the case of receivers having attenuated reception (e.g., indoors) after losing a data connection used for receipt of assistance data.

Abstract: Location of a device within a monitored environment with compromised communication with ranging communication nodes. Specifically, an intermediate device previously located by communication with ranging communication nodes is provided to provide a ranging signal to a device to be located. The device to be located may in turn use a ranging signal received from communication with the previously located device and one or more ranging communication nodes to resolve a location.

Abstract: Data bandwidth reduction in positioning system signals. Specifically, a first, relatively easily acquired signal may be analyzed to determine if and/or to what extent to decimate a second signal. The second signal may comprise a higher encoded data rate (e.g., a chip rate). In turn, decimation of the second signal based on characteristics of the first signal may allow for more efficient processing of the second signal.

Abstract: Location of a device within a monitored environment with compromised communication with ranging communication nodes. Specifically, an intermediate device previously located by communication with ranging communication nodes is provided to provide a ranging signal to a device to be located. The device to be located may in turn use a ranging signal received from communication with the previously located device and one or more ranging communication nodes to resolve a location.