How do you do key management? Do you envision the CAA to send you a letter with your public/private key pair and then you type it into your transponder?
That was proposed as one way of funding the Galileo project.
They were going to encrypt the signal required for GPS approaches, and sell decryption keys.
They dropped the idea when it was pointed out that if the key expired while you were flying an approach, it might be a problem.
It's also just possible that somebody realised there is another player out there, whose GPS is free... and to really complicate things, all the people who make avionics are based in that place.
What will replace GPS if this continues to be a problem?
http://www.nj.com/news/index.ssf/2013/08/manfined32000forblockingnewarkairporttrackingsystem.html
Fears of GPS jamming are always in the press.
In reality, "vandal-level" jamming is not an issue for airborne aircraft because their GPS antennae are properly on the roof, on a metal ground plane. Handheld GPSs may stop working...
I guess you could easily upset ground tracking of aircraft, from a vehicle.
There are instances of GPS jamming that have caused local GPS outage on instrument approach. One airport has numerous reports for this and the culprit has yet to be found. Don't expect your GPS to work if you are near our President.
Is the GPS instrument approach affected at/below the MDA i.e. below a few hundred feet?
I would think that - assuming a proper GPS installation - would require either a powerful jammer (more than a few watts) or an airborne jammer, or a jammer on top of a nearby hill.
But if somebody is sitting on top of a nearby hill, they are going to be highly visible from a helicopter carrying a thermal imager, which is quite a common thing for police helicopters to have (the one based till recently at my airport had one).
Now here's an interesting item from Wikipedia - look at the last paragraph
United Kingdom eLORAN implementation....
On 31 May 2007, the UK Department for Transport (DfT), via the General Lighthouse Authorities (GLA), awarded a 15-year contract to provide a state-of-the-art enhanced LORAN (eLORAN) service to improve the safety of mariners in the UK and Western Europe. The service contract will operate in two phases, with development work and further focus for European agreement on eLORAN service provision from 2007 through 2010, and full operation of the eLORAN service from 2010 through 2022. The first eLORAN transmitter is situated at Anthorn radio station Cumbria, UK, and operated by Babcock Comms, which is part of the Babcock Group PLC.[25]
eLORAN: The UK government has granted approval for seven differential eLoran ship-positioning technology stations to be built along the south and east coasts of the UK to help counter the threat of jamming of global positioning systems. They are set to reach initial operational capability by summer 2014.ref>Nautilus International Newspaper August 2013
The big question is whether anybody is going to make aviation receivers for eLORAN.
Since GPS caused the bottom to fall out of the navigation market best part of 20 years ago, it seems obvious that almost nobody is going to install yet another box just for eLORAN even if one exists.
If I really wanted something which will give me "RNAV" navigation in the (temporary) absence of GPS, I would spend €30k (2011 quote) on a KVH CNS-5000. I had some emails with them in 2011. It accepts an L1 GPS antenna connection at one end (active or passive antenna?) and outputs NMEA (lat, long, pitch, roll and yaw) at the other end. This is not a "certified aviation" product but it will feed some portable moving map device and that will do nicely for enroute, and flying a nonprecision GPS approach.
I don't know what the current price is but it won't be more than the cost of an aviation certified eLORAN receiver, which would be made in miniscule volumes.
However I heard that Bendix/King did make an eLORAN box some years ago, for the US market... does anybody know anything about it?
What concerns me more is these GPS jamming exercises which are NOTAM'd. I have never experienced the effect of one, but 1) I assume GPS jamming has been tested before so they know it works 2) why do it in the public arena - why not limit it to a small radius around some military testing airfield or something? Maybe I am missing the point with these exercises....
The MOD did a lot of exercises off Caithness last year (or the year before) involving GPS jamming from airborne units...all NOTAMed....about as remote as you can get in the UK!
Why would you be concerned about GPS jamming? When it's NOTAMed, you ought to know about it. When not and you're IFR (in the Eurocontrol sense), it's more an issue for ATC than for you (they have to give you headings or waypoints you can determine using VOR/DME). When VFR, well, it's an abnormal situation and you can ask for help. I would have no problem asking whichever station (ATC, airport, 121.5MHz) for assistance.
GPS is my primary means of navigation, I wouldn't take off without it and if it fails, it's a major failure that justifies a cry for help.
