ORIGINAL ARTICLE Vectorized and federated software receivers combining GLONASS and GPS A. Tabatabaei 1 • M. R. Mosavi 1 • H. S. Shahhoseini 1 • K. Borre 2 Received: 26 April 2016 / Accepted: 15 March 2017 Ó Springer-Verlag Berlin Heidelberg 2017 Abstract In traditional federated receiver, all the tracking channels work independently, and there is no interaction among them. However, in vectorized receiver, stronger channels aid others in their tracking. Such architecture makes a receiver to be of interest for positioning in urban canyons and harsh environments. On the other hand, the combination of GPS and GLONASS as the only augmented global constellations is utilized to increase the availability of the receivers which is defined as the percentage of the epochs with enough number of tracked satellites for solv- ing the positioning equation. We report about the software implementation of a GPS-combined-GLONASS Vector- ized Receiver (GGVR) and performance assessment of this architecture in signal attenuation and blocking incidents. We also compare the GGVR performance with a GPS- combined-GLONASS Federated Receiver (GGFR). Experimental tests in different case studies are included. The results show that in the static blocking situation, the GGVR can reacquire the signal immediately after the momentary outage while the GGFR must return to acqui- sition stage. For two dynamic case studies, one in a suburban road and one in an urban canyon, the position results on the road are the same, but in an urban environ- ment, the GGFR has only 88% availability in contrast to 100% availability of the GGVR. Keywords Combination of GPS and GLONASS  Federated receiver  Vectorized receiver  Vector tracking  Urban canyon positioning Introduction Global Navigation Satellite System (GNSS) is a generic term referring to a constellation of multiple satellites for positioning and navigation in a worldwide manner. The US Global Positioning System (GPS) as the high usage system can be combined with other systems such as the European Galileo, the Chinese BeiDou, and the Russian Global Navigation Satellite System (GLONASS) to provide a better precision and robustness. Currently, only GPS and GLONASS are fully operational (Cai and Gao 2009; Gao and Enge 2012; Mattos and Pisoni 2013). Rapid advances in new GNSS technologies require fast prototyping and testing. Software-defined radios (SDRs) serve a flexible platform for researchers and designers. Selecting the receiver parts to be implemented in software depends on the goals of the project. For example, in softGPS as one of the most popular SDRs, the whole data processing from the output of RF front end to position computation is on the software platform. This MATLAB- based software is divided into three main parts. Acquisition as the first part provides rough estimates of carrier fre- quency and code phase of the acquired satellite. Then tracking as the second part refines these values and demodulates the navigation data. Finally, the navigation & M. R. Mosavi M_Mosavi@iust.ac.ir A. Tabatabaei amirtabatabaee@elec.iust.ac.ir H. S. Shahhoseini hshsh@iust.ac.ir K. Borre borre@ssau.ru 1 Department of Electrical Engineering, Iran University of Science and Technology Narmak, Tehran 16846-13114, Iran 2 Samara State Aerospace University, 34, Moskovskoye Shosse, Samara, Russia 443086 123 GPS Solut DOI 10.1007/s10291-017-0615-8