Inside GNSS Media & Research

NOV-DEC 2018

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52 InsideGNSS N O V E M B E R / D E C E M B E R 2 0 1 8 www.insidegnss.com A s stated in Part 1, there is an increasing importance for GNSS open services for our economy, society, e.g., in the field of traffic monitoring and controlling, as well as for timing applications. Because of this it is necessary to enhance the availibility and more importantly the reliability of GNSS ser- vices. In this section of the article, we showcase the results of the performance of the ground system, and a working principle is proven and shown that it is a potential technique in the wide field of signal analyzation and optimiza- tion, be it in the field of multipath, channel coding, authentication or robustness against jamming, spoofing, or other interference for existing GNSS signals as well as for develop- ing potential new GNSS signals. Results Performance of Ground System In a first step, the ground system of the testbed is validated. In this step we verify if the work- ing chain of signal receiving, recording, and post processing works and yields reasonable results. erefore, the Galileo signal in space (SIS) pilot E1C is processed and analyzed and E1B of the SIS is ignored. As in all tests, a sampling rate of 200 MS/s is used and the receiver internal replica signal is a Compos- ite-BOC (CBOC). e tracking results for all three records (from le to right: S-FE, D-FE1, and D-FE2) are plotted in Figure 7. From top to bottom, the C/N 0 , DLL, PLL, and FLL dis- criminators, and the Code Minus Carrier (CMC) values are displayed. e tracking per- formance of the SIS (PRN 3) is satisfying and comes up to expectations. S-FE and D-FE1 are almost identical, because they get their input from the same antenna (Rx1). For the D-FE2 there are slightly different values for C/N 0 , discriminator, and CMC. is is most likely due to the ~40 meter longer coaxial cable and locally different receiver multipath conditions. is degradation is in the normal range and sufficient for the testbed. White Rabbit Time Sync Performance within Ground System In the next step, the FE clock synchronization is evaluated. In the current work, two syn- chronization approaches are tested. First, as a This article — Part 1 was published in the September/October 2018 issue — presents the authors' experience in setting up an airborne pseudolite (UAVlite) with the needed ground-based infrastructure to perform code and phase ranging performance analysis. UAVlites transmit GNSS-like signals free from any local transmitter multipath (in contrast to ground-based transmitters) and can in principle be localized in real-time through a synchronized network of ground stations which may also broadcast the UAVlite positions in real-time. Furthermore, software defined radio allows for the easy broadcast of new navigation signals and testing them in real environments. Here, decimeter code range accuracy and millimeter phase range accuracy has been demonstrated. DANIEL SIMON MAIER THOMAS KRAUS DANIELA ELIZABETH SÁNCHEZ MORALES RONNY BLUM PROF. THOMAS PANY INSTITUTE OF SPACE TECHNOLOGY AND SPACE APPLICATIONS, UNIVERSITÄT DER BUNDESWEHR MÜNCHEN WORKING PAPERS Innovative Test System for GNSS Signal Performance Analysis in Real Environments | Part 2

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