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Open-road groudtruthing

Ground truth reference data in all environments

Maximise the accuracy of groundtruth reference data across your test vehicle fleet.

To analyse whether your ADAS systems have triggered correctly – and if not, why – you’ll want an accurate picture of your vehicle-under-test’s (VUTs) true position, speed, heading, pitch and roll in real-life scenarios.

The most common groundtruth reference system is a GNSS-aided inertial navigation system (GNSS/INS). OxTS GNSS/INS combine cutting edge IMU technology with survey-grade GNSS receivers to deliver cm-level position accuracy alongside precise inertial measurements.

When combined with OxTS’ powerful software features, specifically designed for open-road data collection, users will experience more accurate data, for longer.


The OxTS solution for open-road groundtruth data collection

OxTS GNSS/INS devices for open-road groundtruth data collection

RT3000 v4

For when where matters most

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RT1003 v2

Ready for challenging GNSS environments

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Robust performance in an economical package
(Ethernet and Serial)

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Robust performance in an economical package
(Ethernet and CAN)

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GNSS/INS features for open-road groundtruth data collection

Standard Features

All OxTS GNSS/INS devices come pre-loaded with a number of important features as standard. Whichever device you choose for your data collection project, you will be able to take advantage of the following:


+ ITAR-free hardware – Streamline administration overheads when your hardware needs to be shipped overseas.

+ Dual antenna RTK capability – Achieve high-accuracy position, orientation and dynamics data, even at low speeds.

+ Built-in NTRIP client – Easily access real-time corrections for precise data collection.

+ Free-of-charge support – Every OxTS INS qualifies for complimentary support from our teams in the UK, USA, Germany and China.

+ Sensor fusion as standard – Incorporate data from your other sensors into the OxTS navigation engine with the OxTS Generic Aiding Data (GAD) Interface.

Optional open-road data collection features

To maintain accuracy during an open-road data collection project you will need to overcome an ever-changing set of GNSS and environmental conditions. We suggest the following optional features when collecting data on the open-road:


+ gx/ix tight-couplingSpeeds up RTK reaquisition after transient but complete GNSS outage meaning more accurate navigation data for longer (see example below).

+ OxTS LiDAR Inertial Odometry – Use LiDAR to constrain position drift and improve navigation performance in urban canyons.

+ PTP and gPTP time synchronisation – Master and client functionality makes it easier to integrate your GNSS/INS into an existing payload.

+ External raw data logging – Log all the raw GNSS and IMU data to an external logging device, alongside the data from third-party sensors for simplified accuracy enhancements in post-process.

+ CAN input/output – Gain richer test insights and simplified analysis by logging data to/from your GNSS/INS via CAN.

GNSS vs OxTS gx/ix tight-coupling technology…

Open-Road Groundtruthing Solution Brief

Accurate groundtruth reference data needs a robust localisation solution; a tool that records the position, orientation and dynamics of your vehicle at anytime, anywhere.

This solution brief steps through the aspects that we recommend our customers consider when deciding on their source of localisation for open-road vehicle testing.

Read the solution brief to learn how you can use an OxTS GNSS/INS to validate how your ADAS/AV systems work in the real world.


Open-road groundtruthing

Software Applications

OxTS GNSS/INS are supplemented by a range of software tools to help you collect and understand your data as well as improve your final deliverables. The software applications we recommend you use for open-road groundtruth data collection are mentioned here.



NAVsuite is a complimentary set of software applications that is included with every purchase of an OxTS GNSS/INS. The software allows you to:

+ Configure your OxTS GNSS/INS.

+ Monitor the navigation data from your GNSS/INS in real time.

+ Enhance your real-time test data, in post-process, with an automated command line tool.

+ Plot, analyse and export your test data.


LiDAR Inertial Odometry (LIO)

An optional software feature, OxTS LIO enhances data accuracy in urban canyons using velocity updates from a LiDAR. Compatible with a wide range of 360° field-of-view LiDAR sensors, LIO seamlessley integrates into your existing workflow through a command line tool.

Sensors from the following manufacturers are supported:

+ Velodyne

+ Hesai

+ Ouster

+ RoboSense

+ Riegl

Want to capture accurate ground truth reference data on public roads?

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Public road testing with OxTS

Maximum GNSS coverage with
quad-GNSS support

When testing on public roads, a large proportion of available satellites become obstructed by the physical infrastructure in the environment.

To protect the accuracy of the data, OxTS INS receive signals from four GNSS constellations (GPS, GLONASS, Galileo and BeiDou) which maximises the number of visible satellites at every point along the route.

Read the ‘quad-GNSS vs dual-GNSS’ report to understand the performance improvement gained by using more GNSS constellations during public-road data collection.

Quad-GNSS - more satellites - more RTK

Reduced position drift with
ix/single-satellite aiding

To compute position, GNSS-only and loosely-coupled INS solutions need to track at least four satellites consistently. Any fewer and updates will either stop, or be computed solely by the IMU with increasing error, even if one, two or three satellites are still visible.

With an OxTS solution you are able to make use of every visible satellite – no matter how few are visible at that moment.

When fewer than four satellites are visible, OxTS’ single-satellite aiding technology blends the remaining signals with the output of a high-grade IMU to guard against degrading accuracy in challenging environments.

Fast RTK reacquisition after complete
GNSS outage with gxRTK Inertial Relock

When GNSS signals are temporarily interrupted by bridges and alike, RTK lock is lost and the process of reacquiring it must typically start from scratch. This can mean 10 – 20 seconds is spent outside of RTK after every interruption, no matter how brief.

With an OxTS solution, RTK relock time is reduced to around five seconds as the inertial measurements narrow down the possible solutions.

When you consider how many GNSS interruptions your vehicle encounters on every trip, it’s clear to see the difference this makes to the accuracy of the reference data.

Reduce position drift during GNSS outages with forwards/backwards post-processing

By processing your data twice, first in the same direction it was captured and then in reverse, errors accumulated during GNSS outages can be smoothed out to improve the accuracy of your data.

You can find out more about the real-time performance of OxTS solutions during prolonged GNSS outages here

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