The latest Co-ordinates magazine feed that came across my inbox had an article in it that made me think a bit outside of the square. It’s about the “Dangers of Global Positioning Systems (GPS) and Global Navitation Satellite System (GNSS)” and you can access it directly here: http://mycoordinates.org/feb09/dangers.php
I liked the way the article provided a “what can go wrong” view on GNSS, and some of the things I saw in there made me go “why would someone do that?” (e.g. jamming). But at the end of the day it is an interesting experience to think about what’s going wrong with some of the satellite navigation signals elsewhere – even if we don’t yet experience them here. It made me have a think into what can happen for our clients:
- What is the consequence of someone losing GPS signal through things like canopy, or jamming?
- What impact are the new Global Navigation Satellite Systems (e.g. GLONASS, Galileo, Compass, IRNSS) going to have for our clients?
- What would happen is the US military altered the GPS network (e.g. turned selective availability back on?)?
The article finishes (a bit weakly, I think) with “if it’s not mission critical, don’t worry about GNSS failing”. Is what our clients do “critical”? Well, what do these clients do? They do things like:
- Record sampling sites
- Track animals
- Document plants
- Sample water
- Close and retrieve traps
All of these things use locational information, so a GPS signal failure is a problem. When you’ve mobilized a large team of people to do a field survey, and all of a sudden you can’t find your traps because of a GPS failure, then I’d call this a critical failure.
However, what’s more likely is that you’re going to run out of power, or you will have a software or hardware failure (here I’m talking about GPS equipped PDA units, like the Nomads and Junos we play with here). Power’s easy; take a spare (and charged) battery and a car adapter to top up the charge from your vehicle. Software failures: painful, but recoverable with a reset usually. Hardware failures: bad, but if you’re backing up regularly and using a couple of memory cards and a base laptop, you should minimize the consequences.
I think the really valuable part of this article is the fact that it makes you think about the worst case scenario. There are heaps of thing you can do to help minimize the effects of one of these happening; Pelican cases, multiple memory cards, screen protectors, car chargers, etc. But once we get multiple GNSS up in the sky, that’ll be one more level of protection that I didn’t consider that we needed, but now can’t wait for.
Don’t get me started about mobile phone/internet signals! I think that there’s going to be some pretty big shifts in technology in the future – imagine the benefits of a guaranteed mobile phone signal anywhere on the planet – that will have further changes as to how we collect data. Hopefully these types of technologies will also be environmentally friendly… one thing I don’t think rocket launches of satellites particularly are…
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