Tracker 20 mid-april2024

tracker 20 on Fjalls is still moving progressively in a straight line. It has risen in altitude too. Recent cold weather has stopped solar charging but it is still sending good data. I have deleted fix outliers as it moves less than 5cm but sometimes gets a 1m error.

the tracker had a “glitch” in january – perhaps tilting for a short period or some GPS-related issue – hence the “step” seen in the plots in January.

Fjalls base station is solar charging again

Here we can see the base station battery slowly dropping Bat Voltage during the cold winter – and when the temperatures are below zero it can not charge the battery. After mid feb the temperatures are above zero and the solar charging is working well – bringing the battery back to 100% (around 4V). This means we did the right things to make it work through winters!

IceTracker 20 current status

Looking at tracker 20 on Fjalls we can see it settling into winter – running on battery:

now that average temperatures are below zero the solar charging of the battery is very rare (to save the battery from charging when too cold). It also skipped a few readings in january – which is unusual behaviour – possibly due to its base station misbehaving?

however the Fjalls base stays quite warm (especially in the sun!) so is solar charging OK.

we can see from plotting lat/long that it started to have more outlier readings recently (bottom right). There is usually a very consistent plot of points.

Its altitude jumped upwards in mid december! we can also see the drop due to melting before september and the gradual rise during autumn.

Tracker22 movement and temperatures

Tracker22 has now moved 18m from its original position! – you can see a few outlier spikes due to inprecise GPS fixes but generally the data taken every 3hrs is superb!

Its temperature (not very accurate when it is sunny) has started to dip below zero.

Old dGPS system – ten years ago!

Actually these were installed in 2012 – I just found some more photos showing out first gps ice tracker attempt. All post-processed afterwards (if data recorded!)

our original dGPS recorder on Skalla’ in 2013! Its easy to forget how heavy this was (36kg just the 12AH lead acid batteries!). It ran on its own so it was only possible to check it a couple of times a year. It had three solar panels too!

we painted the tripod red in the hope of finding it – we had to dig it out of the snow one day and it did help.. You can see the tripod bent in the snow..

Early data from the 2023 trackers

on Fjalls – node20 has moved steadily over these six days – showing the sensitivity we have to small movements

on Breida node21 has lost 85cm in altitude in 6 days – (some of that will be the legs melting in). Again the smooth readings show how sensitive the readings are

this early data from the Fjalls base station shows the box gets quite hot in the sun – and the solar panel benefits as the battery is permanently “full”

2023 next generation ice trackers installed

first we installed a new base station closer to the breidamerkurjokull glacier – which had retreated a lot! The new base uses GPRS to send rover data directly to our server.

then installed rover19 at 100m altitude on the glacier

carrying the Fjalls rover20 up to the glacier

new rover20 on Fjalls

We did our first tracker placement using the large UAV (Matrice 300) about 1km away on Breida at an altitude of 130m. We used a camera+release mechanism which gave us a down-looking feed to place it precicely in a safe area (which we can walk to). This tracker 21 has a smaller GPS and radio antenna and a light-weight “quadpod”.

Range testing xbee SX868

Two xbee SX868 modules – with mostly line of sight and a nice 3G antenna at the other end – I obtained a safe 1km range – going up to this 1.5km if a few errors can be tollerated (showing -94 dBm). Over wet an slightly frozen ground I got -95dBm at 1km. I did get a few packets at 2km but it was showing -96 to -100dBm (very weak). This gives us confidence to install GPS units up to 1km away from their base station in Iceland. 1km

update on our next generation ice tracker

Thanks to a lot of work by students over the past year we are on track to producing our new u-blox based trackers for Iceland this summer

Our new choice of microcontroller board running Circuitpython – it is connected to the GPS, its radio The processor is a 120MHz ARM Cortex-M4F. Basicall it has lots of ways to connect to other hardware and is pretty fast – while using very little power.
The dGPS board by Sparkfun allows us to take measurements within about 30-50s, accurate to about 2cm. They use 1/10th of the power of our previous units so our batteries can be smaller.
This is the SWARM sat-coms board by Sparkfun – allowing data communications to the web from anywhere on the planet! We will test this from a base station to shjow that the system can work anywhere and send data back to researchers daily.