The commercial GPS receivers are using weak satellite signals down to -160 dBm considering normal environment conditions. These combine different sources of radio-frequency noise that limit the GPS performance by decreasing the L1 SNR. During high periods of solar cycles radio bursts may exceed 100,000 SFU causing SNR on the Earth's sunlit side to drop for over few decades below the useful limit. This paper presents an overview of solar noise classification, solar cycle progress and predictions, some analysis reports and examples of observed record breaking event in 2006.
This paper presents a quality analysis and comparison of two height reference surfaces. The first is the actual geoid model from the year 2000, and the second is the test geoid model from the year 2010. Quality analysis is based on the comparison of geoid heights determined from measured ellipsoidal and mean-sea-level heights and geoid heights interpolated from the model. The aim of presented activities in high quality GNSS heighting. Besides the quality of the geoid model, the ionospheric disturbances caused by solar storms have a significant impact there.
Ongoing development of the SIGNAL Positioning Service is presented. The service enables real-time positioning with geodetic accuracy. To be able to maintain such a service in long term, high quality national geodetic infrastructure should be realized. To ensure high quality service, the space weather effects on GNSS signals are another important issue, especially variation in solar activity.