After smartphones, wearables are the second most sold GNSS device, with 70 million shipments in 2019 alone. Given this trend, the European GNSS Agency (GSA) was motivated to test smartwatch devices under various conditions. Three devices were selected that, to a certain extent, characterise the Galileo-enabled device offering on the market in 2020: the Suunto 9, Samsung Galaxy Watch Active 2 and Garmin Fenix 6X PRO. The tests delivered some interesting results.
The tests were carried out by the Airbus Systems Engineering and Technical Assistance (SETA) team under a Galileo System Support contract with the GSA. The main objective was to evaluate the navigation performance of the wearables in different receiver configurations and environments. To evaluate the devices’ performance, the tests assessed positioning accuracy and PVT availability.
All the tests were carried out close to an Airbus site south of Munich, and included an open sky static test, an open sky pedestrian test, and an open sky bike test. In addition, there were three suburban dynamic tests (two pedestrian – one with the watch worn on the wrist and one on a backpack, and one bike test), an urban static test, and two forest dynamic tests (pedestrian and bike), both of which had alternating vegetation of broadleaf trees and conifers.
Each test was executed three times in order to cover all the possible GNSS receiver configurations. Subtests with the corresponding GNSS receiver configurations are presented in the table below.
Figure 1: Data collection of forest dynamic pedestrian test case
|Device||Possible GNSS receiver configurations||Release||Single-/Dual-Frequency|
GPS + Glonass
GPS + Galileo
|Samsung Galaxy Watch Active 2||
There is no option to select constellations.
According to the specification receiver supports the following constellations: GPS, Glonass, Beidou and Galileo
|Garmin Fenix 6X PRO||
GPS + Glonass
GPS + Galileo
Table 1: Wearables under test
In general, the devices achieved the highest accuracy when GPS satellites were used together with an additional GNSS. In half of the scenarios, GPS + Galileo showed the best performance.
Suunto 9 outperformed the other two smart-watches in most of the tests by achieving the best positioning accuracy. The PVT availability (up to 90%) of the Suunto 9 was also higher than that of the Garmin and Samsung smartwatches, the only exception being the static scenarios. The results for Suunto 9 are shown in the tables and charts below, demonstrating the achievable performance with the subset of tested devices.
Antenna placement matters for precise testing results
When looking at the best results in terms of accuracy, there is a big difference between wearing the smartwatch on your wrist and having it attached to a backpack. Accuracy is much better when the watch is on a backpack with the watch face, and therefore the GNSS antenna, pointing directly to the sky. The results obtained with the watch worn on the wrist were the worst, because the antenna is not pointing directly at the sky and body shadowing obstructs the signals. This decrease in accuracy could be partially resolved by using higher quality antennas.
|Suunto 9 – suburban test cases||Horizontal accuracy [m] on a given percentile|
|Configuration / Watch placement||50.0%||63.2%||95.0%|
|GPS + Galileo / Wrist||5.29||6.31||14.74|
|GPS + Galileo / Backpack||2.08||2.35||3.44|
Table 2: Comparison of Suunto 9 performance (horizontal accuracy under GPS + Galileo configuration) on wrist and backpack
Another solution is to install the antenna outside the smartwatch, so that GNSS signals can reach the antenna directly. This would also reduce the level of interference between the antenna and other components. However, wearing the watch attached to a backpack or using external antenna is not a solution for the vast majority of users. In any case, there is still room for improvement, especially in more challenging environments, but better performance may be achieved with dual-frequency chipsets, soon to be available on the European market, or with higher quality antennas.
Galileo added value
The tests show that Galileo provides added value in terms of accuracy and availability, of which receiver manufacturers are becoming increasingly aware. This added value was clearly demonstrated with the Suunto 9 results: in 52% of the computed statistics, the GPS + Galileo configuration showed better performance than GPS only and GPS + Glonass. This means that, thanks to Galileo, the data collected during users’ activities will be more accurate and allow for improved performance.
Currently over a hundred wearables are benefitting from Galileo’s added accuracy and availability. To check out if your wearable is on the list, click here.
Figure 2: Example of results: Open sky dynamic bike test case – Suunto 9 – horizontal accuracy
|Open sky dynamic bike test case: Suunto 9||Horizontal accuracy [m] on a given percentile|
|GPS + Glonass||4.78||5.25||7.82|
|GPS + Galileo||2.77||3.32||5.87|
Table 3: Open sky dynamic bike test case: Suunto 9 – horizontal accuracy on a given percentiles
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