Even the GPS system can have faults

“At around 5 AM Pacific Time (1 PM GMT) today (March 7th) the GPS satellites started transmitting inconsistent health information causing Swift Navigation receivers to exclude measurements from any satellites supporting the L2C signal. This has resulted in degraded or unavailable position information and decreased ability to achieve an RTK Fixed solution.”

We kept an eye on the data coming in – as it is not easy to go to Iceland and update the firmware..

This plot shows how the gps behaviour changed after the march 7th announcement. Without knowing this we could have assumed it was caused by something like wet snow cover.


Video of Fjallsjokull

We just edited some footage of the fjallsjokull margin

Here you can see the recently exposed foreland and its moraines.

(video taken with 3DR Solo and GoPro5 – without gimbal – hence the slight wobble)

Some movement data

Since fixing the Fjalls system we have a steady stream of data – showing the glacier moving:

This shows a movement of around 1.5m in just ten days.

October 2017 fieldwork

In October Kirk and Phil went for a quick trip to swap out the Rockblock units and reset the base station at Fjalls.

In October we swapped the Rockblocks to v3 and reset the base station’s fixed location.

View from Fjalls base station. The rover can be seen just above and to the left of the antenna.

Breida movement from the first point as detected in October. This shows the system is working well!

We installed a Brinno timelapse camera looking towards the glacier margin.



Fjallsjokull system deployed

Today we set up two dGPS units to measure the speed of some of Fjallsjökull glacier. We chose an area of ice which is clearly moving forward towards the lake.

Here is the dGPS system setup on Fjallsjokull, with Jane Hart and Frey

The photo above shows a “quadpod” supporting the GPS units – which are an adaptation of those made by Matthew Roberts of the Icelandic met-office. The idea is to be strong enough to cope with winter and cast few shadows (which cause ice to grow). The system is currently measuring its position every 3hrs to an accuracy of about 2cm – using signals from the base station to help it.

the dGPS base station installed on a moraine close to the Fjallsjokull glacier. We used speaker stands burried in rocks to support the GPS antenna (top) and hold its 2.4GHz radio antenna (white stick). Shortly after this photo I accidentally kicked sand into the laptop keyboard – so it was not so easy to use after that!

View of Fjallsjokull with our deployement being almost in the middle of this photo.

ublox m8 tests

Local tests – mainly to debug the python code – of the ublox M8P have produced fast fixes today.

this is over about 30mins in my garden – using about 15 sats.

Iceberg Tracker moves on but seems in trouble

Iceberg tracker temperatures from 9/8/16 to 7/10/16

Iceberg tracker temperatures from 9/8/16 to 7/10/16

We have been checking the iceberg tracker temperature as one way of telling if it is in the sea is a flatter daily variation in temperatures. Here you can see it did regularly read sub-zero at midnight then warmer an noon. Recently however it is showing mainly positive temperatures.

iceberg tracker locations up to 7/10/16

iceberg tracker locations up to 7/10/16

After spending weeks among the small islands in the centre of this map – it has moved south until reaching land again. This dramatic movement may be because the iceberg has broken up.