Anatum Field Evaluation of Bluetooth GNSS Receivers

Beaverton, OR – Anatum Field Solutions, a GNSS equipment rental company, has published the results of an extensive evaluation of Bluetooth sub-meter GNSS receivers it conducted in February/March 2016. The evaluation was conducted on a GNSS test course in Tigard, Oregon with 13 Reference Points (RP) established in open sky, light tree canopy, moderate tree canopy, and heavy tree canopy using an optical instrument operated by a land surveyor and referenced to NAD83/2011 datum with ITRF08 coordinates computed as well.

The evaluation was focused on the performance of Bluetooth GNSS receivers rated at or near sub-meter precision by its manufacturer, and focused on performance in difficult conditions, namely light/moderate/heavy tree canopy, even within arms reach of 30” Douglas Fir trees. The results of the evaluation focus on the accuracy of each receiver in various environments and also the receiver's ability to reasonably estimate the precision in those environments.

“For quite some time, our clients have asked us about the performance of sub-meter GNSS receivers under tree canopy. Until now, we've not been able to show them empirical data,” said Matt Alexander, Vice President at AFS. “We think the data presented in this report will surprise GNSS receiver users about the accuracy of the data they think they are collecting versus the accuracy of the data they are actually collecting.”

Data was collected and analyzed from the Bad Elf GNSS Surveyor, Eos Arrow 100, Geneq iSXBlue II GNSS, Trimble R1 (internal and external antenna), and Trimble Leap. Since AFS also have Trimble GeoXH 6000 w/Floodlight in its rental pool, AFS also included it in the evaluation.

For all receivers evaluated, the source of corrections used was WAAS (SBAS), which are a free source of GPS corrections broadcast by the Federal Aviation Administration (FAA) and are, by far, the most popular source of GPS corrections used by sub-meter receivers in North America. All receivers AFS evaluated were GPS and Glonass-enabled.

Each receiver was run through the test course four times. To be consistent, data was collected during the same time window on each day so as to minimize variability of the satellite constellations. Multiple receivers were used during each test run, up to four. Each receiver was tested using a 2 meter rangepole so as to maximize satellite visibility. Before each test run, receivers were allowed to acquire and track satellites for 15 minutes.