AUSPOS - Online GPS Processing Service
Last updated:30 November 2023
AUSPOS is a free online GPS data processing facility provided by Geoscience Australia. It takes advantage of both the IGS Stations Network and the IGS product range. AUSPOS works with data collected anywhere on Earth.
You can submit dual-frequency geodetic quality GPS RINEX data observed in a 'static' mode to the GPS data processing system.
An AUSPOS report will be emailed to you with the Geocentric Datum of Australia 2020 (GDA2020), Geocentric Datum of Australia 1994 (GDA94) and International Terrestrial Reference Frame (ITRF) coordinates.
AUSPOS Submission checklist
Before submitting your GPS RINEX file/s, please ensure:
- AUSPOS provides a network solution (relative positioning) using a double-difference strategy.
AUSPOS does not use the Precise Point Positioning (PPP) computation strategy.
Dual-frequency measurements from GPS L1 and L2 signals are required.
- Ensure all RINEX files submitted in the same job contain an overlapping period of more than one hour. Otherwise, submit files individually as different jobs.
- DO NOT submit measurements for the current UTC day. Please wait until the next UTC day after 0300 (3 am) UTC time. This allows the RINEX files of reference stations to be downloaded for the current UTC day.
- DO NOT submit receiver raw binary files (for example files with extension: M00, T01, T02, DAT, SBF, TPS...).
- ONLY submit RINEX observation "O" files. DO NOT submit RINEX files with extensions: "N", "M", "G", "L", "P", "H".
- RINEX filenames should NOT contain any special characters, symbols or spaces (e.g. " * ", " _ ", " - ").
- The station name will be read from the first 4 letters of the "MARKER NAME" line in the RINEX header.
- Please make sure the interval (INTEGER only) of measurements is equal to or bigger than ONE second. It is better to have all RINEX files with the same interval. AUSPOS will sample all RINEX files to 30 second intervals.
- DO NOT use special characters for "MARKER NAME" and "MARKER NUMBER" in the RINEX header. ONLY use numbers and/or letters from the modern English Alphabet.
- After the "END OF HEADER" line in the RINEX header, only observation data should be present (Epoch time and Measurements). Please check before submission.
- If BOTH C1 and P1 (C2 and P2) code measurements exist in a RINEX v2 file, P1 (P2) is given priority to be processed. Please make sure all GPS satellites contain P1 (P2) measurements.
- If only C1 (C2) code measurements exists in RINEX v2 file, Please make sure all GPS satellites contain C1 (C2) measurements.
- For RINEX v3 files, C2S (code measurement) and L2S (phase measurement) from L2 frequency will NOT be accepted.
- For RINEX v3 files, currently, the accepted measurements from L1 frequency are C1P and L1P; C1W and L1W; C1C and L1C; and C1X and L1X.
- For RINEX v3 files, currently, the accepted measurements from L2 frequency are C2P and L2P; C2W and L2W; C2C and L2C; C2D and L2D; and C2X and L2X.
- If RINEX files are Hatanaka compressed, please use the lower case "d" for the filename extension.
Frequently asked questions
Online GPS Processing
Online GPS Processing Service?
- AUSPOS is a free online GPS data processing service provided by Geoscience Australia
- AUSPOS takes advantage of both The IGS Stations Network and the IGS product range, and works with data collected anywhere on Earth
- Users submit their dual frequency geodetic quality GPS RINEX data observed in a 'static' mode to the AUSPOS GPS data processing system
- An AUSPOS report will be emailed to you (typically in less than ten mins) containing Geocentric Datum of Australia 202 (GDA2020) 1994 (GDA94) and International Terrestrial Reference Frame (ITRF) coordinates
Question 1.2 - Who can benefit from the service?
The service aims to assist a variety of users from the private and public sector who require GDA and ITRF coordinates. This includes people undertaking surveys such as:
- Reference station positioning
- Remote GPS station positioning
- Ultra-long GPS baseline positioning
- GPS connections to IGS and ARGN and APREF stations
- High accuracy vertical GPS positioning
- GPS network quality control
Question 1.3 - What do I need?
All you need to submit your data and receive your report is:
- Geodetic quality dual frequency GPS receiver observation data in RINEX format
- Access to a web browser with an Internet connection
- An email account
All the GPS data processing occurs in the AUSPOS GPS data processing server, so the type and capability of your computer is NOT important.
Question 1.4 - What do I submit?
- GPS RINEX observation data (navigation data is NOT required);
- the GPS antenna type;
- the GPS antenna height; and
- your email address.
Question 1.5 - How do I get the results?
The results are emailed to you when the processing is complete. A link is also provided to our anonymous ftp server where the report is placed. If you are having trouble accessing either of these, please contact us at firstname.lastname@example.org
Question 1.6 - How fast is it?
This depends on how much data you have submitted. A single site with one day of data should be completed within ten minutes. A multiple site solution might take up to and over twenty minutes. The processing times depend upon system load.
Question 1.7 - How much does this service cost?
There is no cost.
Question 1.8 - What happens to my RINEX files?
AUSPOS will NOT retain a copy of your data set or release any submitted data sets to anyone.
Question 1.9 - Does AUSPOS process real time or kinematic data?
The service does NOT process real time, kinematic, or single frequency GPS data.
Question 1.10 - Does AUSPOS process GLONASS or Galileo data?
The service does NOT process non-GPS data, however; if GNSS data is in the RINEX file it will just be ignored.
Question 1.11 - Why do we make the service free?
AUSPOS provides the service freely to encourage consistency of all precise coordinates used by the GPS community. By making the service free, the Australian GPS community can better compete for contracts throughout the world. Feedback from Australian private sector survey firms shows positive support for the service. They are competing internationally for contracts using the AUSPOS service as an important selling point. Effectively, every small survey/GPS organisation in Australia now has access to a very sophisticated GPS data processing system.
Question 2.1 - How does AUSPOS work?
All computations are undertaken using the Bernese Software System. Bernese is a high precision orbit and geodetic parameter determination software system. For more information see Bernese GNS Software.
The International GPS Service (IGS) product range is used in the computation process. Precise orbit parameters, Earth orientation parameters and coordinate solution IGS products are used.
NOTE: The IGS final orbit product is not available until approximately two weeks after the observation day. The rapid orbit product is available two days after observation. If both the final and rapid orbit products are unavailable, then the IGS ultra-rapid orbit product will be used.
Once a user has submitted a RINEX file, the nearest 15 IGS and APREF stations are used as the reference stations for the processing. That data is retrieved from Geoscience Australia's GNSS Data Archive. A precise solution using a 'double difference' technique is then computed using these stations. The coordinates of the IGS stations are constrained with uncertainties of 1mm for horizontal and 2mm for the vertical.
Question 2.2 - How are observational errors accounted for?
The effects of observation error sources, such as receiver clocks, troposphere and ionosphere are taken into account, either through modelling, or estimation of related parameters. All the computations are undertaken according to IERS conventions.
A summary of the computation standards are provided as an appendix to all processing reports.
Question 2.3 - What Reference Frame is used?
All coordinates are computed in ITRF2014. For Australian users, Geocentric Datum of Australia 2020 (GDA2020) and 1994 (GDA94) coordinates are also provided in the report. GDA coordinates are determined by an AUSPOS derived ITRF to GDA transformation model. The accuracy of this transformation is sub-centimetre.
Question 2.4 - Does the system work with data collected anywhere on Earth?
Yes, the system was designed to work anywhere on Earth because the IGS network has global coverage. We download all IGS core station data and the APREF station data as soon as they are available in the Geoscience Australia GNSS data archive.
Question 3.1 - How do I read the processing report?
The processing report is provided in Adobe PDF format.
Question 3.2 - What parts of the report should I check carefully?
It is recommended that you read the whole report thoroughly to familiarise yourself with the AUSPOS process. The important quality statistics related to your processing job are located in Sections 3-5 of the AUSPOS Report. This includes information such as the Coordinate Precision and Ambiguity Resolution.
Question 3.3 - What are the 'Derived AHD' and 'Derived Above Geoid' heights?
In the GDA section of the AUSPOS report, the user is supplied with a 'Derived AHD' height. This is a height computed using AUSGeoid2020 model. The offset between the ellipsoid and AHD is computed using Geoscience Australia's AUSGeoid2020 product and subtracted from the ellipsoidal height providing the user with a Derived AHD height. The AUSGeoid2020 model of ellipsoid to AHD separation values only extends 33 km offshore. Between 33 km and 50 km offshore, the AUSGeoid2020 ellipsoid to AHD separation values are linearly blended with Gaussian weighting with the DTU15 Mean Sea Surface model. The closer to shore, the higher the weighting of AUSGeoid2020 values. From 50 km outwards, the model is only the DTU15 Mean Sea Surface model For more information, refer to the AUSGeoid09 page.
In the ITRF section of the AUSPOS report, the user is supplied with a 'Derived Above Geoid' height. This is a height relative to the Earth Geopotential Model 2008 (EGM2008).
Question 3.4 - The report provides GDA and ITRF coordinates, but what about WGS84 coordinates?
ITRF and WGS84 are generally considered to be equivalent (to within 0.1 m).
Question 5.1 - Why do I have to specify the GPS antenna?
To achieve the highest quality processing results, attention needs to be paid to the type of antenna used. Using the incorrect antenna type can introduce significant bias (greater than 10 cm in the vertical component) and noise into the computed coordinates.
The actual observation point on a GPS antenna is called the electrical phase centre. The location of this phase centre is represented by a mean constant offset from the physical point on a GPS antenna, known as the Antenna Reference Point (ARP), and an additional variable offset that is dependant on the transmitting satellite's elevation.
The properties of the electrical phase centre are different for every type of antenna. Importantly, the electrical phase centre can be modelled provided you know the antenna type.
Question 5.2 - What is the antenna height?
The antenna height is the vertical distance from the ground mark to the Antenna Reference Point (ARP). The ARP is the physical point on a GPS antenna that measurements are typically reduced to. The ARP varies between antenna types. As a WARNING, the ARP is rarely the top of the Antenna Ground Plane. The ARP height should NOT be confused with slant and other instrument height measurements commonly used in GPS processing.
Question 5.3 - What type of GPS antenna do I have?
AUSPOS uses the IGS antenna naming convention. The IGS - Naming Convention Document provides more information.
Further information regarding the specifications of antennas can be found on the National Geodetic Survey (NGS) antenna calibration web site.
Question 5.4 - What happens if I choose the DEFAULT(NONE) antenna?
If you choose the DEFAULT(NONE) antenna type; no antenna phase centre model or offset is applied.
If you set the antenna height to 0.0000 m and choose an antenna type, then the position of the ARP is computed.