GNSS Payload and Signal Characterization using a 3m Dish Antenna

Jose Vicente Perello Gisbert, Nikolaos Batzilis, Gustavo Lopez Risueño, Julia Alegre Rubio

Abstract:	GNSS satellite signal/payload characterization in orbit is normally performed with high diameter dish antennas in order to reduce multipath and increase the received signal to noise ratio levels. Small dish antennas are normally not used, but still they can provide good capabilities to be analyzed. A 3m dish antenna was purchased for GNSS research in ESA-ESTEC European Navigation Laboratory (ENL) located in Noordwijk, the Netherlands. This antenna has a COTS pedestal-engine able to track complete GNSS satellites passes, and it is connected to GNSS receivers and a spectrum analyser/digitizer. This antenna is a laboratory tool and is used for R&D and experimental purposes. This measurement system has been used to get very valuable results about state of the art GNSS satellites. Payload/signal characteristics have been obtained with such a small dish antenna. The studied GNSS satellites are GPS IIF-IIRM-IIR-IIA, GLONASS-M and COMPASS (MEO satellites). First figures of merit results are about the payload signal coherency: code-carrier coherency and differential group delay (differential code-carrier coherency), both in terms of stability versus time and elevation. These measurements are based in dual frequency tracking and iono-delay removal. The second figure of merit is onboard EIRP (Equivalent Isotropic Radiated Power). In the frame of code-carrier coherency (CCC)analysis for GPS, the impact of the receiver early-late correlator spacing is studied on the L1-CA signal. This will assess the impact of the signal distortions in the CCC stability. GPS satellites from the IIRM and IIF families are studied under this point of view. In order to characterize the payload signal coherency, hardware COTS GNSS receivers are connected in parallel to the dish antenna. For the EIRP calculation, an automatized spectrum analyzer/digitizer is utilized. This paper shows the results that a small 3m dish antenna can obtain for payload signal coherency stability characterization at cm level and, EIRP. In addition the used setup and methodology (based in textbook-public methodologies) are described.
Published in:	Proceedings of the 25th International Technical Meeting of the Satellite Division of The Institute of Navigation (ION GNSS 2012) September 17 - 21, 2012 Nashville Convention Center, Nashville, Tennessee Nashville, TN
Pages:	347 - 356
Cite this article:	Gisbert, Jose Vicente Perello, Batzilis, Nikolaos, Risueño, Gustavo Lopez, Rubio, Julia Alegre, "GNSS Payload and Signal Characterization using a 3m Dish Antenna," Proceedings of the 25th International Technical Meeting of the Satellite Division of The Institute of Navigation (ION GNSS 2012), Nashville, TN, September 2012, pp. 347-356.
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