Since its launch in 2001, Geoscience Australia's online positioning service (AUSPOS) has continued to be a widely used tool for the online processing of geodetic GPS data for surveying, mapping, geodetic, geophysical, hydrographical, military and other applications. On 20 March 2011, Geoscience Australia released an updated version of the service, AUSPOS2. This update implements recent advances in analysis software and strategies, the reference frame ITRF2008, AusGeoid09 and the latest transformation parameters between ITRF2008 and GDA94. AUSPOS2 now delivers ITRF2008 coordinates with an uncertainty less than 10 millimetres to users within 3-5 minutes while continuing to provide Australian users access to GDA94 coordinates and derived AHD heights to the highest achievable accuracy. This talk will overview the AUSPOS2 system and how users can best exploit this free service.

This GA Record reports findings regarding the absolute vertical rate of movement (i.e. the rate at which the land is moving up or down with respect to the centre of the Earth) of 13 Pacific Island tide gauges over the period 2003 – 2018 based on the analysis of Global Navigation Satellite System (GNSS) data and levelling data.

The gnssanalysis Python package is designed to provide the public with a source of useful python functions and classes that help with processing of GNSS observations. The functionality found within the package includes: - reading of many standard file formats commonly used in the geodetic community including SP3, SNX, RNX, CLK, PSD, etc. into pandas dataframes (Also writing certain file formats) - transformation of data, for example datetime conversions, helmert inversions, rotations, transforming geodata from XYZ to longitude-latitude-altitude, etc. - functions for the download of standard files and upload to other sources (e.g. s3)

An application dated 20 August 2012 for verification of a reference standard of measurement under Regulation 12 of the National Measurement Regulations 1999 was received from the Ultimate Positioning Group Pty Ltd for verification of GDA94 position on their owned or managed station monuments. This report documents the processing and analysis of GPS data observed by the Ultimate Positioning Group Pty Ltd during three 7-day periods from 6 to 12 May 2012 (day of year 127 to 133) for the station STHE, from 13 to 19 May 2012 (day of year 134 to 140) for the station DELO and from 22 to 28 July (day of year 204 to 210) for seven stations BTYP, BURN, CAMP, DEVO, LAUN, RANE and SCOT, to satisfy the position verification requirements.

Geoscience Australia (GA) designed two types of Global Navigation Satellite Systems (GNSS) antenna mount adaptors which allow antenna north reference marks to be easily and reliably aligned to the true north without changing the height of the antenna with respect to the reference mark. The antenna adaptors evaluated are proposed to be installed on GNSS Continuously Operating Reference Station (CORS) across Australia as new sites are built and commissioned or existing sites upgraded. The purpose of the report is to document the antenna adaptor testing experiments undertaken between 15/09/2021 and 18/10/2021, and determine if the mount adaptors have a significant impact on positioning quality when installed with GNSS antennas on typical GA CORS pillars. Specifically, the mount adaptors were evaluated for their effect on site multipath, position difference, and antenna calibration phase centre variations (PCV) models. Two types of mount adaptors were evaluated, a small adaptor with a diameter of 60 mm and a thickness of 26 mm and a large adaptor with a diameter of 100 mm and a thickness of 26 mm. Both adaptors were fabricated using solid stainless steel. After analysis of observations collected on typical GA tall (~1.5 m) and short (< ~0.2 m) pillars, with and without the adaptors installed, the following conclusions and recommendations can be made: a) The impact of the two types of antenna mount adaptors is small, causing less than 0.02 m change in average multipath based on one week data for L1 and L2 frequencies. b) There is around 1.1 mm for the tall pillar and 2.5 mm for the short pillar change in average position difference induced by the two types of adaptors for both horizontal and vertical components based on one week data. c) There is no significant impact (less than 1 mm for both L1 and L2 frequencies) on the PCV models induced by small antenna adaptor. d) The small antenna mount adaptor is recommended for tall pillar installations and the large mount adaptor is recommended for short pillar applications.

This report overviews the status and development of the Asia Pacific Reference Frame (APREF) project, which is a major activity of the Geodetic Reference Framework for Sustainable Development Working Group of the United Nations Global Geospatial Information Management for Asia and the Pacific (UN-GGIM-AP), and the Reference Frame Sub-Commission 1.3e (SC1.3e) of the International Association of Geodesy (IAG). In this work, the APREF Continuously Operating Reference Station (CORS) network is reviewed. This is followed by an overview of the analysis methodology and strategy adopted for processing of data from the network. Coordinate time series, velocities as well as other parameters are generated for 450 CORS sites across the Asia-Pacific region and 200 International GNSS Service (IGS) core stations located around the world. An accuracy assessment of the output and products, including the estimated position and velocity field is presented. The position solutions have an internal accuracy of 1-4 mm and 4-8 mm in horizontal and vertical components, respectively, determined from position repeatability of the weekly solutions. When compared with the published IGS14 velocities for the 173 common sites, the velocity solutions have an external accuracy of 0.02 ± 0.29 mm/yr, 0.01 ± 0.32 mm/yr, and 0.08 ± 0.54 mm/yr for north, east and vertical components, respectively. Products of the APREF Project include the daily and weekly solutions, combined weekly solutions, position time series of long-term solutions, coordinates and velocity field of the CORS network in ITRF2014.

We are pleased to announce the forthcoming release of Ginan version 3, a suite of open-source Global Navigation Satellite System (GNSS) software tools developed and maintained by Geoscience Australia in collaboration with industry and academia under the Positioning Australia program. Ginan serves as a precise point positioning (PPP) engine to produce real-time products that support high-precision positioning. Its versatility is demonstrated through its applicability to various geodetic and positioning activities, including computation of daily coordinate solutions, precise satellite orbit determination, computation of satellite clocks and biases, atmospheric modeling, and data quality assurance and quality control. These products effectively mitigate real-time errors associated with GNSS observations and are openly accessible as a centimeter-accurate correction service. The primary objectives of Ginan are: (1) showcase Australia's unique modelling and analytic systems for multi-GNSS real-time processing, delivering precise positioning products to both the Australian and international Positioning, Navigation, and Timing (PNT) community; (2) offer expert advice on navigation system performance over Australia; and (3) provide state-of-the-art GNSS analysis center software to universities and research organizations, thus fostering Australia's leadership in geospatial technology development. In this presentation, we will provide an overview of Ginan version 3, highlighting its new features, the current development status, and the strategic roadmap for its continued use as an operational service. We will provide examples of Ginan’s usefulness as a platform for research and innovation including its use as the processing engine for research into atmospheric anomalies from the Tonga volcano eruption through monitoring travelling ionospheric disturbances that could be used as early warning and tsunamigenic predictors for disaster risk and reduction; and observations of the Turkyia earthquake. The release of Ginan version 3 marks a significant advancement in GNSS data processing and positioning capabilities, contributing to the broader scientific community's understanding and utilization of geospatial technology. Abstract to be submitted to/presented at the American Geophysical Union (AGU) Fall Meeting 2023 (AGU23) - https://www.agu.org/fall-meeting

Data collected from Geodetic GPS observation campaigns over the last 15 years. This data set is from non-continuous GPS sites. It is a combination of surveys undertaken by Geoscience Australia, State collaborators and international collaborators.

<div>Within the preparation for the release of the International Terrestrial Reference Frame 2020, the International GNSS Service (IGS) analysis centers (ACs) issued the results of the third reprocessing campaign (IGS Repro 3) of all the GNSS network solutions backwards starting from 1994. For the first time, the IGS reprocessing products include not just GPS and GLONASS, but also the Galileo constellation. In this study, we show the methodology and results of the orbit combination provided by the IGS Analysis Center Coordinator (IGS ACC) at Geoscience Australia. The quality of the provided combined orbit products was cross-checked with the individual IGS Repro3 AC contributions. The internal consistency of the individual AC solutions with the combined orbits was assessed based on the root mean square of the 3D orbit differences. In 2020, the mean consistency of the combination is at the level of 9, 23, and 15 mm for GPS, GLONASS, and Galileo, respectively. The external validation was performed using Satellite Laser Ranging (SLR) observations. We proposed a novel approach to handling detector-specific biases in the results of SLR validation, reducing the standard deviation of SLR residuals by up to 15% for Galileo FOC satellites. The method is based on bias referencing to single-photon SLR stations that are not affected by the retroreflector signature effect. The proposed approach increased the internal consistency of the SLR dataset, facilitating the detection of orbit modeling issues. The standard deviation of SLR residuals of the best individual solution versus the combined equals 13/14, 15/16, 17/16, 16/16 mm for Galileo-FOC, -IOV, GLONASS-K1B, -M, respectively. Therefore, the combined solution can be considered equal or slightly better in quality compared to the best individual AC solutions. Searching for patterns in SLR residuals for different satellite-Sun-Earth geometries reveals that some issues in orbit modeling are not fully diminished for individual ACs. Eventually, we proved that the delivered combined orbit product may be considered the best solution overall. The combined solution benefits from the best individual solutions for each satellite type.</div> <b> Citation:</b> Zajdel, R., Masoumi, S., Sośnica, K. et al. Combination and SLR validation of IGS Repro3 orbits for ITRF2020. J Geod 97, 87 (2023). https://doi.org/10.1007/s00190-023-01777-3

Geoscience Australia (GA) manages a network of 150 Continuously Operating Reference Stations (CORS) across Australia, Antarctica and the Pacific. In addition, GA supports data archiving and distribution of a further 450 CORS that contribute to the Asia-Pacific Reference Frame (APREF) project. The primary objectives of this network have been to maintain the National Geodetic Reference System and support scientific endeavours. GA is currently shifting the focus of our GNSS networks from a scientific model to one which supports both science and industry. This requires GA to meet higher standards of data availability and accessibility, latency and metadata accuracy. Further to this GA recognises the need to take advantage of Australia¿s unique geographical location and move towards providing access to multi-GNSS data in modern formats such as RINEX 3 and RTCM 3.2 (MSM). This presentation looks at the current state of the Australian CORS network and highlights our planned transition and expected challenges in moving from a scientific model to an operational model supporting modern data format and streamlined metadata.