Australia and New Zealand SBAS and PPP Testbed. System on Track

Since, 2017 a second-generation satellite augmentation system has been demonstrated in Australia and New Zealand. This system provides Satellite Based Augmentation (SBAS) and real-time Precise Point Positioning (PPP) capabilities through the SBAS L1 and L5 signals broadcast from the Inmarsat 4F1 geostationary satellite. The Australia and New Zealand SBAS and PPP Testbed is promoted by Geoscience Australia (GA), Land Information New Zealand (LINZ) and FrontierSI. The Testbed system has been developed in collaboration with industry partners, including Lockheed Martin, Inmarsat and GMV. The primary objective of the Testbed is to assess the benefits of satellite navigation technologies, including integrity assurance and high precision techniques, for applications in the transportation and other industrial sectors. The Testbed SBAS transmissions began in May 2017, and the PPP service transmissions started in October 2017. By September 2019, the SBAS/PPP services have accumulated almost two years of broadcasts. At the beginning of the Testbed transmission, the capability to provide an L1/L5 augmentation (as indicated by the DFMC SBAS draft standards) was limited by the lack of sufficient number of GNSS (GPS, Galileo) satellites supporting an L5 signal. For this reason, it was decided to configure the Testbed to provide augmentation for GPS users based on the GPS L1/L2 iono-free combination instead of the nominal DFMC use of L1/L5. Moreover, the limited number of Galileo satellites available at that time (only 13 operational satellites) needs to be taken into account when analysing the range of improvement achievable with a DFMC service. Since 2017 more than ten new GPS and Galileo satellites have become operational. The fact that all the new satellites broadcast the L5 frequency has made feasible the transition to a GPS L1/L5 + GAL E1/E5 mode. This configuration is more aligned with the actual definition of the SBAS DFMC standard. The main goal of this paper is to provide an update on the Testbed service definition, infrastructure status and performances achieved to date from the point of view of the system developers. The paper will be organized in the following main sections. - Description of the Australia and New Zealand SBAS Testbed architecture and discussion of the technologies used in the deployment of the Testbed, as well as provide insights on the challenges faced and the evolutions implemented during the ongoing Testbed operations. - Analysis of the results and performance achieved by the Testbed during almost two years of operations through the review of Testbed service monitoring data. - SBAS and PPP performance results based on augmentation of the new GNSS satellites available between August 2018 and February 2019. An analysis of the addition of the new L5-enable satellites and the comparison of the L1/L5 results versus the initial L1/L2 configuration is provided.