National Positioning Infrastructure Capability
Positioning Australia offers precise positioning of 3-5 cm accuracy through our network of continuously operating Global Navigation Satellite Systems (GNSS) ground reference stations. This is a valuable service for specialist users who need to position equipment and assets to a very high level of precision. The network spans all of Australia and its external territories and consists of stations that are both owned and operated by Geoscience Australia and stations operated by third parties that have been integrated through data licensing agreements. The precise positioning service is available anywhere there is mobile phone or internet coverage.
The network has been designed to support a variety of precise positioning applications, ranging from monitoring the movement and deformation of the Australian continent to enabling centimetre accurate positioning in real-time within areas of mobile internet coverage.
Positioning Australia is upgrading the network of 130 ground reference stations through our National Positioning Infrastructure Capability (NPIC) program, to ensure the reliability and resilience of the network into the future. The program is also installing around 70 new ground reference stations around the country to expand the range of the network and fill gaps in coverage. This will improve the performance and coverage of precise positioning services across the nation.
About the project
As part of the Positioning Australia program, Geoscience Australia is establishing a national network of continuously operating GNSS reference stations that will enable the delivery of 3-5 cm accurate positioning services via the internet in areas of mobile phone coverage. NPIC’s reliable and robust network of GNSS reference stations will improve access to precise positioning services to users across the country, especially in regional areas.
To achieve this, we are:
- Modernising and expanding Australia’s fundamental geodetic GNSS network. This modernised network will track all the modern GNSS constellations and signals being broadcast over Australia, provide increased levels of resilience and ensure Australia has an accurate and reliable reference frame.
- Densifying the network, through partnerships with other government and industry network operators to ensure positioning services are available in the areas where they are needed.
- Improving the accessibility and reliability of our systems to ensure that the data from the network is accurate and reliable.
When complete, the GNSS network will span all of Australia and its external territories and consist of stations that are both owned and operated the Commonwealth and stations that are operated by third parties. The network has been designed to support a variety of precise positioning applications ranging from the movement and deformation of the Australian continent to enabling centimetre accurate positioning in real-time.
How to get access
Geoscience Australia provides open access to the historic data and data streams observed from all stations that contribute to the National Positioning Infrastructure Capability.
The data can be accessed through the Geoscience Australia GNSS Data Centre.
The GNSS data are also available for access via subscription through a network of Australian based Value-Added Resellers (third-party service providers). These Value-Added Resellers combine the NPIC data streams with their own infrastructure to provide supported positioning services, which are available across most areas of Australia with access to mobile phone coverage.
How it works
GNSS based positioning overcomes errors caused by the complexity of changes in the Earth’s atmosphere and the dynamic nature of operating GNSS satellites. This is typically done by connecting to data streams from fixed reference stations with precisely known positions. These reference stations create data streams which can be used to estimate GNSS errors and send them to the users in a corrected form. There are a number of ways in which these corrections can be estimated. The technique selected will depend on the user requirements, equipment and their proximity to the reference stations. These techniques include:
The most common and most accurate technique is Real-Time Kinematic (RTK) positioning, provided by the NPIC network. RTK is based on the theory that the reference station and user are located close together (closer than 50 km) and therefore subject to the same errors.
An alternate to RTK positioning is Precise Point Positioning (PPP). PPP depends on satellite clock and orbit corrections, generated from a network of fixed reference stations. Once these corrections are generated they can be applied by the user regardless of how close they are to the reference stations. PPP does have some limitations on accuracy and performance.
More recently, a hybrid approach has been developed which combines the accuracy and performance of RTK with the flexibility of PPP. This technique, known as PPP-RTK, requires reference station network with stations about every 150 km which are used to generate corrections for the satellite clocks, orbits and the atmospheric errors.