High Rate Performance Assessment of GNSS Raw Data

Kurzfassung

Over the past years the Institute of Communications and Navigation (IKN) has developed the so called ´Experimentation and Verification Network´ (EVN) in cooperation with the German aerospace company Jena-Optronik GmbH. The EVN has to be considered as a new basic infrastructure realising the reception, transmission, and distribution of any kind of GNSS data as well as derived products via Internet in nearly real time. For this purpose a set of sensor stations - each equipped with GNSS-receivers and partly meteorological sensors, with a processing host, and additional components to fulfil the requirements of a complete remote control system - are currently installed on specific world wide locations to support the research and development activities of the IKN in the field of GNSS/Galileo verification and application. The main functionalities of the EVN will be shortly presented by description of its basic architecture and the interaction between all integrated components. Besides the intended purpose to support the research and development activities of the IKN, the added value of the ´Experimentation and Verification Network´ is determined by the implemented processing components realising the GNSS data assessment and the provision of derived data products in the context of the GNSS/Galileo verification and of a Local Element development. A case in point of such processing modules is a high-rate phase processor developed by IKN using one particular feature of the EVN to operate with 50 Hz GNSS data. Its objectives and features cover the independently detection of cycle slips and data gaps per carrier, the estimation of the momentary phase noise, the locating of non-regular phase fluctuations, and last not least the quantification and validation of the performance of GNSS/Galileo phase measurements in real time. The capabilities of the phase processor will be verified considering gathered results at different locations under different propagation conditions. The gain of the advanced high-rate processing technique will be demonstrated by comparison with conventional 1 Hz results, whereby the attention will be focused on the phase behaviour during periods of increased ionospheric conditions (perturbances) and on the achievable continuity of phases, for which a constant ambiguity can be assumed. Furthermore by-products of the phase processor like real measured rates of ionospheric propagation errors will be analysed together with the corresponding signal strength behaviour provided by an amplitude processor of the EVN. The last part of the presentation will give an overview about the utilisation strategies of the EVN and the implemented processing components in areas like Galileo in-orbit verification, establishment of local augmentation services and space weather services for the communication and navigation user community.