Sat-nav devices face big errors as solar activity rises

Date: 1/3/2010

Source: BBC News

The sun is reportedly heading towards another period of high activity. It is expected that during this period GNSS-based navigation devices are likely to have larger errors than under normal solar conditions.

According to NASA, the next maximum in solar activity is predicted for June 2013. During this time GNSS-based navigation will be affected by two separate sources of error.

One will come from solar flares, which will send out a large amount of Electro-Magnetic radiation and charged particles towards the Earth. The majority of GNSS receivers on Earth will not be able to distinguish the relatively weak GNSS signals from satellites amongst the increased background radiation. This is likely to result in short periods, of approximately a few minutes in duration, when GNSS receivers will not be able to receive any signals.

The second source of error will come from the ionosphere. The increased solar activity will affect the number of ionised particles in the ionosphere, which in turn will affect the speed with which GNSS signals travel through it. This will create errors in the position calculations. The magnitude of errors is likely to vary depending on the location and time of day, but in the UK it is likely to be in the region of 10 metres.

All GNSS-based equipment is likely to be affected by errors resulting from the increased solar activity.

Key words: Galileo, Geographic information, In-vehicle systems