Publications
On the influence of RF absorbing material on the GNSS position KU Leuven
Reflections of the GNSS signal around the antenna induce an error in the measurement of the satellite–receiver distance and therefore should be avoided as much as possible. One solution often used to mitigate these reflections is to apply radio frequency (RF) absorbing material to the antenna, its support or its site. Such material could however alter the antenna phase delay and, in turn, alter the position as calculated from the GNSS ...
Monitoring of UTC(k)'s using PPP and IGS real-time products KU Leuven
© 2014, Springer-Verlag Berlin Heidelberg. The time transfer technique based on Precise Point Positioning (PPP) has proved to be a very effective technique allowing the comparison of atomic clocks with a precision of a hundred picoseconds, and with latency of 2 days. Using satellite orbit and clock information from the IGS real-time products, it is now possible to compute very precise time transfer solutions based on PPP in near real-time, i.e., ...
Calibration of Galileo Signals for Time Metrology KU Leuven
Using global navigation satellite system (GNSS) signals for accurate timing and time transfer requires the knowledge of all electric delays of the signals inside the receiving system. GNSS stations dedicated to timing or time transfer are classically calibrated only for Global Positioning System (GPS) signals. This paper proposes a procedure to determine the hardware delays of a GNSS receiving station for Galileo signals, once the delays of the ...
Near real-time ionospheric monitoring over Europe at the Royal Observatory of Belgium using GNSS data KU Leuven
© 2014 N. Bergeot et al., Published by EDP Sciences. Various scientific applications and services increasingly demand real-time information on the effects of space weather on Earth's atmosphere. In this frame, the Royal Observatory of Belgium (ROB) takes advantage of the dense EUREF Permanent GNSS Network (EPN) to monitor the ionosphere over Europe from the measured delays in the GNSS signals, and provides publicly several derived products. The ...
Influence of different GPS receiver antenna calibration models on geodetic positioning KU Leuven
© 2013, Springer-Verlag Berlin Heidelberg. To better understand how receiver antenna calibration models contribute to GPS positioning error budget, we compare station positions estimated with different calibration models: igs05.atx, igs08.atx and individual antenna calibrations. First, the impact of switching from the igs05.atx antenna calibration model to the igs08.atx antenna calibration model is investigated using the EUREF Permanent Network ...
Advances in Multi-GNSS Time Transfer KU Leuven
This paper proposes a method to combine GPS and GLONASS measurements for time transfer in All-in-View, using calibration data for both GPS and GLONASS. GLONASS has to date a complete constellation, but its use for time transfer is made difficult by the existence of biases for each satellite-receiver pair. These biases contain both a receiver contribution, due to the different frequencies emitted by the different GLONASS satellites, and a ...
Ongoing Renewal of the ROB PTF KU Leuven
In order to increase the reliability of the PTF at ROB and hence the reliability of UTC(ORB), the time was high for replacement of some major equipment. Obviously this was the ideal opportunity to give the PTF an upgrade and to solve some problems and issues. First the "old" PTF architecture was studied to pinpoint its shortcomings and possible improvements. Then a "new" PTF layout was defined and is gradually being implemented. This new PTF ...
A Practical Attack on KeeLoq KU Leuven
KeeLoq is a lightweight block cipher with a 32-bit block size and a 64-bit key. Despite its short key size, it is used in remote keyless entry systems and other wireless authentication applications. For example, there are indications that authentication protocols based on KeeLoq are used, or were used by various car manufacturers in anti-theft mechanisms. This paper presents a practical key recovery attack against KeeLoq that requires 2 16 known ...