Web connected RTK GNSS
We are measuring ice flow with the help of new dGPS technologies. Earlier research used dGPS recordings with traditional high cost devices. Our research is using the latest generation of lower cost real-time kinematic dGPS so that more sites can be monitored for the same cost. It also means the loss of one unit in a glacier has a reduced financial impact. Our system automatically provides location measurements from synchonised dGPS units, which wait for a static RTK fix and then sleep between sessions. The readings are sent once per day to a web server via the Iridium satellite network, allowing the system to operate anywhere in the world. The fixes are accurate to around 2cm and they take less than two minutes to acquire, with only 50 bytes to transmit (vs hundreds of kBytes with dGPS recordings). This reduces the power requirements by around a 50th and opens up the possibility of year-around live monitoring.
In 2016 we carried out a simple experiment to track an Iceberg with the help of Formula E. This helped us carry out trials in 2017. Thanks to National Geographic we extended the system in 2018 and will monitor into 2020.
in 2017 we installed differential dGPS units on two Glaciers in Iceland. Each site has one fixed base station and one moving unit on a glacier. The two are synchronised to wake up when readings are needed. The location data are sent back to the UK via Iridium Satellite messaging and combined with other data to study the glaciers.
Here is a Schematic of Piksi Multi based node showing how we power up the GPS/Iridium separately when we need them. Also the use of multiple batteries to increase capacity and avoid duplicating power supplies. The Espruino Pico is programmed entirely in MicroPython making it easy to adapt in the field.
This is the second Fjalls base station location – covering a wider area of the glacier.
this is the newer position of the Fjalls rover – higher on the glacier but with a good signal from its base station.
See our Blog posts on data from Breida
Imaging, GPR and other Surveys
We also carried out a quadcopter imaging survey in order to create a 3D model of the Fjallsjokull margin:
This “fly through” was created by moving through the 3D model – it is not a quadcopter video. Models like this can be used to monitor the changes over time as we produce one of the same area each year.
Together with the dGPS units we carried out a GPR survey of the ice being measured at Breida’ and left a timelapse camera observing the ice margin at Fjallsjokull.
We’re very happy with the concepts of our design – and many spot measurements do provide good data for analysis. Due to Covid we didn’t deploy new things recently but concentrated on designing a lower power system with better communications capabilities. We look forward to trying the Ublox F9P based system in 2022.