Abstract: Methods and apparatus for generating a test signal for a PNT configuration, and for testing a PNT configuration are disclosed. One such method comprises the steps of using one or more GNSS jamming signal detectors (100) to detect at least three different types of threat signal, each being an RF-based man-made GNSS jamming signal, and recording, to a database, information for the threat signals; receiving, from the database, information for at least one of the threat signals; generating a corresponding threat signal from the received information; and combining the corresponding threat signal with a PNT signal via a signal combiner to generate the test signal.

Abstract: A ground-based source of a jamming signal capable of disrupting a GNSS satellite-based navigation system, for example a GPS jammer, is located with a detector carried by a suitable platform, for example an airborne UAV or missile. The detector, when the platform is at a first location, measures a characteristic of the jamming signal. The platform and its detector are then moved to a chosen second location, from which a further measurement of the jamming signal is made. The measurements made by the detector are then used to determine the location of the source of the jamming signal.

Abstract: A method of processing signal data including an unencrypted portion and an encrypted portion, the method including: receiving, at a receiver, the signal data; processing a sample of the signal data to provide a processed signal sample including data relating to the encrypted portion of the signal data and data relating to the unencrypted portion of the signal data, comparing the unencrypted signal data with at least one reference signal to determine information including at least one of (i) the time at which the signal was sent from the source and (ii) the identity of the source; requesting, based on the determined information, and from a source remote to the receiver, a set of encrypted reference signal samples; comparing, on a processing device remote to the receiver, the set of encrypted reference signal samples with the received encrypted signal data to identify any matching signal samples.

Abstract: Methods and apparatus for generating a test signal for a PNT configuration, and for testing a PNT configuration are disclosed. One such method comprises the steps of using one or more GNSS jamming signal detectors (100) to detect at least three different types of threat signal, each being an RF-based man-made GNSS jamming signal, and recording, to a database, information for the threat signals; receiving, from the database, information for at least one of the threat signals; generating a corresponding threat signal from the received information; and combining the corresponding threat signal with a PNT signal via a signal combiner to generate the test signal.

Abstract: A ground-based source of a jamming signal capable of disrupting a GNSS satellite-based navigation system, for example a GPS jammer, is located with a detector carried by a suitable platform, for example an airborne UAV or missile. The detector, when the platform is at a first location, measures a characteristic of the jamming signal. The platform and its detector are then moved to a chosen second location, from which a further measurement of the jamming signal is made. The measurements made by the detector are then used to determine the location of the source of the jamming signal.

Abstract: A method of processing signal data including an unencrypted portion and an encrypted portion, the method including: receiving, at a receiver, the signal data; processing a sample of the signal data to provide a processed signal sample including data relating to the encrypted portion of the signal data and data relating to the unencrypted portion of the signal data, comparing the unencrypted signal data with at least one reference signal to determine information including at least one of (i) the time at which the signal was sent from the source and (ii) the identity of the source; requesting, based on the determined information, and from a source remote to the receiver, a set of encrypted reference signal samples; comparing, on a processing device remote to the receiver, the set of encrypted reference signal samples with the received encrypted signal data to identify any matching signal samples.

Abstract: A receiver is configured to receive signals wirelessly from a plurality of pseudolites, each signal including information defining a pseudolite from which the signal was transmitted. The receiver is configured to determine an estimated location based on which combination of two or more pseudolites the receiver is currently within range of. The receiver may determine the estimated location independently of a time taken for each one of the signals to reach the receiver from the two or more pseudolites. The signals may be formatted according to a global navigation satellite system GNSS specification.