Lost GPS signals now verified as caused by Northern Lights

William Atkins
Monday, 23 June 2008 19:31

Science - Climate

The signal from the GPS receivers, located on the surface of the Earth (specifically, northern Norway) was reduced dramatically in strength during this activity, and the three receivers had continuing problems keeping a “lock” on the GPS satellites orbiting the Earth overhead.

Their abstract states, “The entire duration of the event was about 10 s and was recorded by all three receivers. Intense, short duration events such as these are not clearly observable in the 1-min scintillation index (S4) because they do not necessarily last for the entire minute. In spite of their short duration they can cause a receiver to lose lock because of their intensity.”

The researchers went on to say, “The geomagnetic conditions were disturbed at this time with the interplanetary magnetic field southward for a period of several hours. Magnetometers from the IMAGE network in Scandinavia showed evidence of a 2000 nT substorm.”

The researchers then compared the GPS measurements with all-sky camera (ASC) data. They concluded that the reduction in signal strength was due to the “GPS ray paths crossing electron density structures associated with the aurora.”

They based their decision on the fact that: “The ASC images reveal moving auroral structures at the same time as the GPS signals show movement of the ionospheric regions causing fading. The results indicate that at high latitudes low-elevation GPS signals can suffer sudden fading due to E-region auroral events.”

Most importantly, they state, “This is the first time that a direct connection has been established between the loss of lock on a GPS receiver and diffractive fading caused by auroral precipitation.”

What is GPS and what is our near-time outlook on auroral activity, in the northern and southern hemispheres, over the next few years? Please read on to find out.