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A characterization of the signal anomaly of SVN49 is presented. A mathematical model is developed to relate the observed multipath to the internal signal reflection. The analyses provided are based on measurements, which have been collected during a dedicated tracking campaign with a 30-m dish antenna. Data on the L1 and L2 frequency have been collected with four different receivers. In addition, IQ samples have been recorded directly with a spectrum analyzer. The multipath combination of the receiver measurements on L1 and L2 is analyzed to demonstrate the effect of the signal reflections on different correlator spacing. The capability to suppress the signal reflection with receiver multipath mitigation methods is demonstrated. Finally, preliminary estimates of the attenuation, delay, and phase shift over elevation are obtained from an IQ sample analysis.

Modeling of both nominal distortions and signal anomalies (i.e., evil waveforms) is crucial for an accurate user error budget for satellite based augmentation systems (SBAS) and multi‐frequency multi‐constellation ground based augmentation systems (GBAS). Such analysis is of particular interest for the ongoing standardization work of L1‐L5 SBAS services. In this paper we propose a method to jointly estimate analog and digital distortion of a satellite navigation signal based on high gain antenna measurements. Joint estimation of analog and digital distortion is needed in case the estimates of these two satellite signal imperfections are interdependent. This is the case when the time‐bandwidth product of the satellite signal is small. The impact of both satellite imperfections on the ranging performance of a GNSS receiver is assessed by means of analytical formulations which make use of the cross‐power spectral density (CPS) between the distorted and the ideal signal and of the power spectral density (PSD) of the nominal (ideal) signal. Copyright © 2016 Institute of Navigation

All seven operational GPS Block IIR‐M satellites experienced short maintenance periods in February 2017. It was later identified that the satellites' transmit power of different L1 signal components had been changed during this maintenance. The total radiated power of the satellites remains constant, but the powers of the C/A‐code and the P(Y)‐code signals have increased while the powers of the M‐code and the intermodulation product have reduced. Further examination reveals a more efficient use of the total available power on the spacecraft as more power is available for the three navigation signals on L1. Observations from geodetic GNSS receivers were analyzed to demonstrate the effect of the change in L1 signal power distribution on the measured C/N0 of the C/A‐code and P(Y)‐code for different receiver types. High‐gain antenna data collected before and after the maintenance periods are used to analyze improved utilization of the available power through the reduction of the losses caused by the intermodulation product. © 2018 Institute of Navigation

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