Acquisition and tracking of s-band signals of navigation with Indian constellation (NavIC)

Abstract

The IRNSS satellite network covers a large area of the India with 7 satellites, 3 geostationary and 4 that are geosynchronous. IRNSS signals are transmitted in the L5 and S-Bands. The L5 band frequencies range from 1164.45-1188.45 MHz and the S band frequencies range from 2483.5-2500 MHz.NavIC is the IRNSS satellite constellation network that can be employed to a variety of applications. In order to achieve this signal must be acquired and tracked. IRNSS signals have PRN sequences unique for each satellite. These sequences are used to scramble and encrypt the signal, in order for a receiver to acquire the signal, it needs to have the same PRN sequence as that of the sending satellite, this is achieved in acquisition using an efficient search method. Once the PRN sequence is generated at the receiver it has to be tracked continuously to ensure that there is no loss of signal at a later point, which is achieved in the tracking phase. Several factors can lead to noise generation in the satellite signal; this can lead to either a Doppler shift in carrier or shift in PRN both leading to loss of signal, thus a correctional loop is also implemented in the tracking phase to correct the effect of noise.