Positioning technology is no longer a background utility – it’s time to position it front and centre. Last year, geospatial technology contributed $39 billion to Australia’s GDP, with annual output projected to reach up to $90 billion in a decade, according to the Geospatial Council of Australia. For those in the business of building, maintaining, or regulating physical assets, the positioning tech you use will directly affect the project, efficiency, and long-term value.
At the same time, public investment is transforming the baseline. The Australian Government has committed $224.9 million to the Positioning Australia program to deliver real-time positioning with accuracy of 10 centimetres nationwide, a step change from the 5 to 10 metre accuracy of unaugmented satellite positioning. With systems like SouthPAN, satellite-based augmentation now improves GPS accuracy across Australia and New Zealand to less than a metre, and in some cases to around 10 centimetres. With that in mind, those in surveying need to determine when to rely solely on GNSS, when to introduce inertial systems, and when to transition to full mobile mapping.
GNSS: The foundation of modern surveying technology
Global Navigation Satellite Systems (GNSS) refer to the comprehensive set of satellite constellations used for positioning, navigation, and timing, including GPS, GLONASS, Galileo, BeiDou, and SouthPAN. Professional guidance, such as the RICS ‘Use of GNSS in land surveying and mapping’, recognises GNSS as a core tool for control surveys, mapping and engineering set out across a wide range of scales.
At a practical level, high-accuracy GNSS receivers now support multi-constellation and multi-frequency tracking, and work with correction services such as RTK, PPK, and PPP. This allows survey and GIS teams to move from metre level to centimetre level positioning for tasks such as:
- Establishing and maintaining control networks
- Cadastral and engineering surveys in open sky environments
- Utility and local government asset inventories
- Environmental and agricultural monitoring over large areas
GNSS hardware paired with modern iOS, Android and Windows Bluetooth-based receivers, such as the Eos-GNSS Arrow can deliver submeter to centimetre accuracy, making it possible to use high-accuracy GNSS with mainstream field apps rather than specialised data loggers.
Known limitations remain, however. Multipath, signal blockage by buildings or canopies, and complete outages in tunnels or under bridges can degrade or interrupt GNSS solutions. These constraints are precisely where inertial systems begin to matter.
What inertial systems add to the positioning stack
An Inertial Navigation System (INS) computes relative position over time using rotation and acceleration data from an Inertial Measurement Unit (IMU). In essence, the INS integrates accelerometer and gyroscope measurements to estimate velocity, position and attitude, including roll, pitch and heading.
Because an INS is self-contained, it does not require external radio or satellite signals. This brings clear advantages for surveying technology:
- Operation in GNSS challenged environments such as tunnels, urban canyons, dense forests and built-up corridors
- Continuous high-rate attitude information, which is essential for mobile LiDAR, imaging and direct georeferencing
- Short-term robustness against outages that would leave GNSS alone without a reliable solution
The main drawback of a standalone INS is drift. Small biases in accelerometers and gyroscopes accumulate over time, making pure inertial navigation unsuitable for long-duration absolute positioning without external updates.
This is why, in practice, most advanced surveying systems do not treat GNSS and inertial systems as alternatives. Instead, they integrate the two.
What are the benefits of IMU in GNSS surveying?
Integrating an IMU with GNSS in surveying improves reliability and accuracy by providing continuous motion and attitude data when satellite signals are degraded or lost. The IMU bridges short GNSS outages, stabilises heading and tilt, supports direct georeferencing for LiDAR and imaging sensors and reduces the need for repeat field visits due to gaps in trajectory data.
GNSS and inertial system integration for mobile mapping
Modern mobile mapping systems for road, rail, utilities and UAV platforms almost always adopt a GNSS-aided INS architecture. The inertial system provides high-rate motion and attitude information, while GNSS delivers absolute position and corrects drift through sensor fusion algorithms.
Integrated navigation is now central to mobile mapping and reality capture:
- GNSS and INS are the most commonly used technologies in mobile mapping, integrated to provide continuous position and orientation for the mapping platform in dynamic conditions.
- GNSS/INS integration is a core component of mobile mapping systems on both terrestrial and airborne platforms, including UAV-based photogrammetric mapping in precision agriculture, mining, construction, and environmental monitoring.
In commercial products, GNSS/INS integration now underpins:
- Direct georeferencing software that processes GNSS and inertial trajectories for aerial, land and marine mapping sensors, enabling centimetre-level accuracy within hours of data capture using services such as Trimble CenterPoint RTX.
- Flight management and mobile mapping systems that combine GNSS-aided inertial solutions with camera and LiDAR payloads for corridor and infrastructure mapping.
From a surveying technology perspective, the value proposition is clear. GNSS-aided inertial systems deliver:
- Continuous position and orientation through short GNSS outages
- Higher fidelity trajectories for LiDAR and imaging sensors, resulting in tighter point clouds and better feature extraction
- Reduced dependence on dense ground control, particularly for UAV mapping and long linear corridors
For peer organisations assessing mobile mapping or upgrading their motion survey capability, the decision is less about whether GNSS/INS integration is beneficial and more about where it should sit in the portfolio.
Laser scanning, GNSS and inertial systems on large projects
The choice between laser scanning and traditional GNSS-based workflows on large projects is often a false one. They are complementary, not mutually exclusive.
Laser scanning, particularly LiDAR, produces dense three-dimensional point clouds that can be exploited for structural assessment, terrain modelling and digital twins. Reviews of laser scanning in infrastructure and geotechnical applications highlight its ability to deliver frequent, detailed assessments in challenging environments when combined with appropriate positioning and processing workflows.
Positioning technology underpins the value of these scans:
- Static terrestrial laser scanning often relies on survey control established by GNSS and a total station
- Mobile LiDAR on vehicles, UAVs or backpacks typically couples a LiDAR sensor with GNSS-aided INS to georeference every point in time and space.
On large linear projects such as roads, rail and pipelines, or in complex environments such as tunnels, the decision pattern generally looks like this:
- GNSS only: suitable for open sections where control, centrelines and simple asset features are sufficient
- GNSS + total station: appropriate when localised high precision control is required around structures
- GNSS aided INS with LiDAR or high resolution imaging: preferred where continuous three-dimensional information is valuable along the entire corridor, particularly in GNSS-challenged areas
The real question is not whether to choose laser scanning over GNSS, but when to introduce laser scanning that is tightly integrated with GNSS and inertial systems so the data can support engineering, asset management and digital twin use cases over time.
A practical framework for choosing positioning technology
For teams evaluating GNSS, inertial systems, and integrated mobile mapping, it is helpful to apply a structured set of questions.
What accuracy and completeness do you actually need?
Different projects have different tolerances:
- Asset inventories may operate comfortably at decimetre to half metre accuracy
- Engineering, deformation monitoring, and close-range structural mapping typically demand centimetre-level consistency.
High-accuracy GNSS systems, utilising RTK, PPK, or PPP corrections, can meet these requirements in suitable environments. In contrast, GNSS-aided INS is often necessary for mobile platforms and complex conditions.
What is the operating environment?
Environment defines risk:
- Open rural landscapes, coastal zones and offshore operations can often rely on high-accuracy GNSS combined with augmentation services like SouthPAN, which improve accuracy from 5 to 10 metres to better than a metre and, in some cases, to around 10 centimetres.
- Urban canyons, tree-lined streets, dense vegetation and tunnels require robust handling of GNSS outages. Here, an inertial system enhances GPS accuracy by propagating position and attitude information during periods without satellite signals and then realigning when signals are restored.
Static, kinematic or high-speed mobile mapping?
Project dynamics shape technology selection:
- Static surveys with limited movement can be served by high-accuracy GNSS backed by careful observation strategies and redundancy.
- Kinematic surveys (for example, on foot or using ATVs) often benefit from tightly coupled GNSS and IMU solutions for smoother trajectories.
- High-speed mobile mapping on road or rail corridors almost always justifies a full GNSS-aided INS with LiDAR or imaging sensors and direct georeferencing software, precisely because the cost of data gaps or misalignments is so high.
How will data flow into your enterprise systems?
Positioning technology only delivers value when it harmonises with GIS, asset management and engineering platforms. High-accuracy GNSS receivers that are device-agnostic and Bluetooth-enabled enable field teams to work directly within corporate GIS apps while still achieving sub-metre or centimetre-level accuracy.
On the mobile mapping side, software that fuses GNSS and inertial data, leverages wide-area correction networks, and includes quality control workflows can reduce acquisition costs, avoid repeat surveys, and support more automated ingestion into enterprise systems.
How does this align with your risk and ROI profile?
The geospatial sector in Australia is projected to deliver a cumulative economic impact of $689 billion by 2034, with current activity supporting around 12,000 full-time jobs across the economy. Positioning technology decisions sit directly within that productivity narrative.
Investing in high-accuracy GNSS systems, inertial integration, and mobile mapping platforms has clear commercial implications:
- Fewer field revisits and reduced rework caused by gaps in coverage or poor trajectories
- Stronger safety outcomes by minimising the exposure of crews on live roads or hazardous sites
- Richer datasets that can be reused for design, asset management and digital twin initiatives
Conclusion
GNSS will remain the foundation of surveying technology for many years, particularly as national programs like Positioning Australia and SouthPAN lift baseline accuracy to the decimetre level across the continent. For straightforward open-sky projects, high-accuracy GNSS is required.
However, as organisations move deeper into mobile mapping, complex infrastructure corridors and GNSS-challenged environments, inertial systems are no longer optional. Integrating IMU, GNSS, and laser scanning within a coherent workflow enables teams to maintain reliable positioning and orientation, support modern direct georeferencing approaches, and unlock the full economic potential of Australia’s geospatial investments.
4D Global can position your tech to put you on the map
If you are planning a new survey, asset capture or mobile mapping program, speak with 4D Global about your positioning requirements, operating environments and existing software stack. The team specialises in GNSS, inertial systems, laser scanning and mobile devices for field-based survey and data collection, and can help map project needs to an appropriate technology mix.
4D Global also provides training, rentals and support so you can validate a solution in the field before making long-term commitments. This combination of high-accuracy GNSS systems, GNSS and inertial integration expertise and practical field experience gives you confidence that your next project will capture the right data the first time.
Contact 4D Global to learn how to better utilise GNSS to position your business front and centre.