Pulse shaping investigation for the applicability of future GNSS signals in indoor environments

It has been commonly recognized that the use of Global Navigation Satellite System (GNSS) signals for indoor positioning is extremely challenging due to the significantly attenuated signal power and the presence of strong multipath components. However, with the advent of new GNSS signals the position accuracy is expected to be improved in outdoor environments and their applicability indoors shall be re-examined. In indoor environments, it is likely that the pure GNSS solution will not be sufficient; assisted-GNSS or any solutions where combined communication and navigation receivers are employed are very promising candidates to solve this problem. One issue in this case is the bandwidth limitation, introduced via the pulse shaping at the transmitter side and/or the bandwidth limiting filters at the receiver side. This is the problem addressed here. More precisely, in this paper we investigate the impact of different pulse shape filters on the tracking accuracy of the future Global Positioning System (GPS) and Galileo signals. The simulation results indicate that Chebyshev and Butterowrth filters are good candidates compared to the infinite bandwidth rectangular pulses and in terms of error variance degradation.