Abstract: An instrument landing system (ILS) is described. The ILS comprises a plurality of antennas and a plurality of antenna radio units (ARUs). Each ARU of the plurality of ARUs operates to generate a modulated RF signal provided to a different one of the plurality of antennas for transmission. The ILS further comprises a central processing unit that operates to control the ARUs to adjust synchronization between the modulated RF signal provided by the ARUs to the plurality of antennas for transmission.

Abstract: An instrument landing system (ILS) is described. The ILS comprises a plurality of antennas and a plurality of antenna radio units (ARUs). Each ARU of the plurality of ARUs operates to generate a modulated RF signal provided to a different one of the plurality of antennas for transmission. The ILS further comprises a central processing unit that operates to control the ARUs to adjust synchronization between the modulated RF signal provided by the ARUs to the plurality of antennas for transmission.

Abstract: A control system in communication with one of an aircraft navigational aid system and an aircraft surveillance system is described. The control system obtains measurement data associated with radio frequency (RF) signals transmitted by the one of the aircraft navigational aid system and the aircraft surveillance system from an unmanned aerial vehicle (UAV) reporting the measurement data. The control system also determines whether the measurement data indicates the RF signals are within a range of values based on a location of the UAV in an airspace proximate to the one of the aircraft navigational aid system and the aircraft surveillance system. The control system further controls the RF signals transmitted by the one of the aircraft navigational aid system and the aircraft surveillance system based on the measurement data and the location of the UAV. Methods performed by the control system are also described.

Abstract: A test metric for satellite sent GNSS code signals is proposed, wherein a signal sent by each satellite i is received at different GNSS receivers, and bias-removed, averaged over the receivers and normalized measurement values are derived out of autocorrelation function values. A correlation matrix Ri,n is built from a matrix Xi,n containing the measurement values in the form of measurement value vectors {right arrow over (X)}i,k from the present time epoch tn and from previous time epochs tk with k=1, . . . , n?1, wherein a principal component analysis is done of matrix Ri,n, wherein a transformed vector {right arrow over (T)}i,n=PCi,nT·{right arrow over (X)}i,nT is calculated, with PCi,n containing at least two eigenvectors having the largest eigenvalues of all eigenpairs.

Abstract: A system for determining the position of an aircraft comprises an emitter arranged at the aircraft for emitting a signal, at least two receivers arranged at different locations for receiving the signal emitted by the emitter, and an evaluation device which is designed to determine an aircraft position based on the known positions of the receivers at the time of the reception of the signal and on a characteristic of the signal emitted by the emitter and received by the receivers. The invention proposes that at least one of the receivers is located above the aircraft, and that the evaluation means is designed to determine a vertical position (ALT) of the aircraft from the signal received by the receivers and the known positions of the receivers.

Abstract: A system for determining the position of an aircraft comprises an emitter arranged at the aircraft for emitting a signal, at least two receivers arranged at different locations for receiving the signal emitted by the emitter, and an evaluation device which is designed to determine an aircraft position based on the known positions of the receivers at the time of the reception of the signal and on a characteristic of the signal emitted by the emitter and received by the receivers. The invention proposes that at least one of the receivers is located above the aircraft, and that the evaluation means is designed to determine a vertical position of the aircraft from the signal received by the receivers and the known positions of the receivers.

Abstract: A test metric for satellite sent GNSS code signals is proposed, wherein a signal sent by each satellite i is received at different GNSS receivers, and bias-removed, averaged over the receivers and normalized measurement values are derived out of autocorrelation function values. A correlation matrix Ri,n is built from a matrix Xi,n containing the measurement values in the form of measurement value vectors {right arrow over (X)}i,k from the present time epoch tn and from previous time epochs tk with k=1, . . . , n?1, wherein a principal component analysis is done of matrix Ri,n, wherein a transformed vector {right arrow over (T)}i,n=PCi,nT·{right arrow over (X)}i,nT is calculated, with PCi,n containing at least two eigenvectors having the largest eigenvalues of all eigenpairs.

Abstract: A Global Navigation Satellite System receiver for position determination receives from a multitude of satellites a respective GNSS code signal, which are correlated with a reference code signal to obtain an autocorrelation function. A multitude of function values of the autocorrelation function at different discrete chip spacings (chosen asymmetrically with respect to a prompt chip spacing) are analyzed and used in obtaining a test metric. Using the test metric, a decision is made whether the received GNSS code signal is suitable or unsuitable (thereafter excluded) for a position determination due to multipath signal components. A bias removal is performed taking into account corresponding function values of an autocorrelation function that would result from a received GNSS code signal of the satellite unaffected by multipath signal components. This provides a simple method for operating a GNSS receiver minimizing errors in position determination caused by multipath signal components.

Abstract: A Global Navigation Satellite System receiver for position determination receives from a multitude of satellites a respective GNSS code signal, which are correlated with a reference code signal to obtain an autocorrelation function. A multitude of function values of the autocorrelation function at different discrete chip spacings (chosen asymmetrically with respect to a prompt chip spacing) are analyzed and used in obtaining a test metric. Using the test metric, a decision is made whether the received GNSS code signal is suitable or unsuitable (thereafter excluded) for a position determination due to multipath signal components. A bias removal is performed taking into account corresponding function values of an autocorrelation function that would result from a received GNSS code signal of the satellite unaffected by multipath signal components. This provides a simple method for operating a GNSS receiver minimizing errors in position determination caused by multipath signal components.