STUDIES ON VARIATION OF GNSS SIGNAL STRENGTHS FROM INDIA

Commercial GNSS receivers provide the measure of received satellite signal strength in terms of Signal to Noise ratio (SNR) or Carrier to Noise Ratio (C/N0), through in many cases the terms are used interchangeably. The received signal strength affects the receiver performance is one of the measure of usability of satellites for position solution purpose. GNSS signals passes through the atmosphere and are affected by atmosphere, therefore the values are also used for atmospheric research purposes. This papers presents the results of long-term studies on GPS, GLONASS and GALILEO signal strengths and their variation patterns using data from a commercial multi-GNSS receiver operating from Burdwan in eastern India. It may be observed that generally signal strength values increases with decreasing fluctuations for increasing elevation angle of satellites and saturates above certain elevation angle. The three constellations offer slightly different signal strengths and new generation Galileo and GLONASS satellites provides higher satellite signal strengths. The results would be useful in understanding the GNSS signal strength for various purposes