New GNSS Signals Demodulation Performance in Urban Environments

Abstract : Global Navigation Satellite Systems (GNSS) are increasingly present in our everyday life. The interest of new users with further operational needs implies a constant evolution of the current GNSS systems. A significant part of the new applications are found in environments with difficult reception conditions such as urban or indoor areas. In these obstructed environments, the received signal is severely impacted by obstacles which generate fast variations of the received signal's phase and amplitude that are detrimental to both the ranging and demodulation capability of the receiver. One option to deal with these constraints is to consider enhancements to the current GNSS systems, where the design of an innovative signal more robust than the existing ones to distortions due to urban environments is one of the main aspects to be pursued. A research axis to make a signal more robust, which was already explored, is the design of new modulations adapted to GNSS needs that allows better ranging capabilities even in difficult environments. However, other interesting axes remain to be fully explored such as the channel coding of the transmitted useful information: users could access the message content even when the signal reception is difficult. This is the context of this paper.