The Arrow Gold® GNSS, with its L-Band support, provides worldwide decimeter positioning to your smartphone, tablet or notebook computer. With numerous reference stations worldwide and L-Band satellites distributing coverage from 75°N to 75°S, all of the earth’s landmass is covered.
When an Arrow Gold is subscribed to an H10 service, SafeRTK® takes over when RTK network becomes unavailable and maintains your accuracy for the rest of the outage period.
With Atlas Correction Service and Arrow GNSS receivers, you can acquire 4-50 cm positioning accuracy anywhere in the world, depending on your subscription:
GNSS (Global Navigation Satellite System) is a general term describing any satellite constellation that provides positioning, navigation and timing services worldwide. GNSS receivers (including many mobile phones) receive radio signals from these satellites and GNSS positioning works by simple triangulation. Because we know the speed of a radio signal (speed of light), your receiver can compare the device time at the point it receives the signal to that of the time-stamped signal to provide the time it has taken to travel to the receiver. Knowing speed and time, the receiver can therefore calculate the distance to each satellite using the Distance = Speed * Time calculation. The receiver then uses the principle of triangulation (using 3 or more satellite distances) to calculate your accurate position on the Earth’s surface.
How accurate depends on a few factors. An uncorrected position, as calculated by your phone, will position you with an accuracy of around 6 meters. This does not sound great however for the purposes of something like satnav this is good enough to position you on the correct road. If, however, you are a surveyor, Asset Capture would need to involve a more accurate position to underpin Asset Location. The asset could be a water valve which has been buried, overgrown or even flooded. If an operative needs to close that valve, then the minimum requirement would be to use accurate Asset Location to find and turn it off.
The reason a mobile phone can currently only provide accuracies of around 6m is that most cannot use all the GNSS constellations, and they cannot recognise and reject inferior quality signals, such as those reflected from other surfaces. These are called multipath signals and, because they are indirect, they will position you incorrectly.
Currently, the most accurate GNSS positioning systems require specialist 3rd party receivers, such as those provided by Eos Positioning Systems and Leica.
These can easily be ‘plugged in’ to existing phones and tablets as they already have the required multipath rejection technology and can track additional satellite constellations for higher accuracy including the SBAS (Satellite Base Augmentation System). This combination can underpin a much more accurate Asset Capture experience by providing sub-meter accuracies.
If your work mandates even higher precision, then you can also plug in RTK (Real Time Kinematic) correction services, such as Leica Smartnet. RTK provides connection to a network of base stations which are surveyed to the millimetre to provide further corrections live in the field. This can add the power of cm-level accuracy to your Asset Capture system and is well within NRSWA 300mm or PAS256 100mm standards.
SmartNet covers UK & Ireland, while Atlas provides global coverage.
L-Band is a frequency band, from 1 – 2 GHz, allocated to satellite navigation and telecommunications. Atlas is a GNSS global corrections service delivered by L-band.
Atlas has approximately 200 reference stations worldwide. They cover all of Earth’s landmass.
Atlas offers worldwide coverage through two methods: via L-Band satellite, and via the Internet. L-Band distribution covers from 75°N to 75°S, and there is no geographical limit to Internet coverage.
This depends what subscription you take.
Once convergence is achieved, the accuracy remains consistent as long as the Arrow antenna has a clear view of the sky.