Galileo E5a/E5b Snapshot Software Receiver for Weak Signal Environments
- Paper number
IAC-09.E2.1.1
- Author
Mr. Sergio Carrasco-Martos, Delft University of Technology, The Netherlands
- Year
2009
- Abstract
Indoor and dense urban positioning has received much attention in the last years, since they constitute the bottleneck in the extension of Location-Based Services (LBS) in mobile networks. Global Navigation Satellite System (GNSS) positioning has turned out to be a very suitable candidate to enable this kind of services. This has motivated in recent years an increasing research activity on signal processing techniques for indoor GNSS receivers. However, the main limitation faced by indoor GNSS receivers is due to the complex propagation of the GNSS signals in indoor sites. These limitations have given rise to so-called high sensitivity GNSS receiver architectures. With the future deployment of Galileo, Global Navigation Satellite System (GNSS) performances will improve, meeting future user needs, thus allowing positioning services in weak signal scenarios (indoor, urban canyons). Hence, Galileo will quite possibly provide the required accuracy to become an enabler of LBS, positioning itself as privileged candidate to enter a massive business market that can increase the demand of GNSS receivers and applications in the future. But Galileo receivers are still in their first phases of matureness, and therefore an extensive research activity needs to follow to enable Galileo receivers to become one day suitable for such applications. To this aim, a Master Thesis was carried out by the author at the European Space Agency (ESA). The result of that work is an innovative acquisition-based Galileo software receiver that does not require a tracking stage (therefore simplifying the design). Research results prove that the applied signal processing techniques allow processing of long periods of signal to perform Range-Doppler estimation in an efficient way by intensive use of the Fast Fourier Transform (FFT). Moreover, by means of long coherent correlations and non-coherent integrations, high sensitivities can be achieved in weak signal scenarios, avoiding the effects of secondary code transitions. The receiver performs as expected as it is able to achieve sensitivities of typical indoor scenarios (between 15 and 20 dBHz). It is also discussed how the E5 pilot signals can be combined (i.e., coherently or non-coherently) to get an increase in performance, this way giving hints on possible future Galileo E5 signal acquisition strategies. Finally, the success of the design also proves that a transition from current hardware-based receivers to software-based receivers, with the consequent advantages in cost, size and complexity, is plausible and therefore should become a trend of the GNSS receiver market.
- Abstract document
- Manuscript document
(absent)