How do trucks interfere with GPS signals? I have seen this written a number of times but I have no idea by what mechanism they can interfere with or jam signals between a satellite and an aircraft.
So you can’t extrapolate from your personal experience to the whole of aviation.
I am grateful as always for you setting me on the right track Timothy… The 2nd total loss was 2014.
How do trucks interfere with GPS signals?
The drivers use GPS jamming devices so they can exceed their max driving hours 
And probably for other purposes e.g. road charges.
..and also so they can visit brothels.
The actual receivers in modern day iPad must be far far better than those in KLN-94 and 430, because they can acquire and maintain a signal while inside the aircraft, on the floor or whatever while the certified versions need a dedicated external antenna. (The 4th generation iPad can even get a fix inside a B-747!). I’ve not had an iPad LOS in recent times, or for that matter a 430 or KLN-94 outage either. Despite that, I carry a dual iPad setup with a fully charged standby, a fully charged spare, and another spare in the baggage. And a phone. And the paper maps and airfield VACs. And DME, 2 VOR’s, etc. And 2 Radios.
My one gripe is that iPad battery life is not long enough for a good days flying (4-5 Hrs with the brightness turned up) and both SD and FF restrict the number of spares to one. I’m often using two together, one with SD and one with FF weather radar over 3/4G. So I also have fag lighter charger and battery pack, which just about keeps up on iPad. Overheating? Seen it on iPad 4th gen., never on iPad 2 which still works fine with SD and FF. The floor mounted vents in PA-28 are a quick remedy and if no pax, then a good place out of the sunlight.
I’m glad the CAA have joined the real world. When I first flew, ‘temporarily uncertain of position’ was a recurring nightmare, as was being shouted at by controllers in the vicinity of their airspace (In those days, they called you before you busted). Today the utlity of VFR flying is utterly transformed and trips that seemed impossibly challenging then have become routine now. I’m sure I’m not the only one taking advantage of this new world of VFR flying.
Aveling wrote:
The actual receivers in modern day iPad must be far far better than those in KLN-94 and 430, because they can acquire and maintain a signal while inside the aircraft, on the floor or whatever while the certified versions need a dedicated external antenna.
It has more to do with the level of integrity required. This isn’t like picking up a weak VOR signal, from a single point, it is a question of how many satellites you can see compared to how many you need for the job in hand.
The iPad will give you some kind of position (sometimes with a big circle of uncertainty around it) with as few satellites as it can. The TSO-129() and -146() specs call for more integrity, and the level of integrity depends on the flight operation (ENR, TERM, LNAV or LPV.)
The shift in CAA thinking on GPS is rather regrading day light and busy days airspace busts, for which GPS integrity is rather optional as long as you keep good margins, this can be sorted to some degrees by an iPhone/iPad GPS and geo-loc map application
The only caveat is that they have less integrity errors as Tim mentioned, they like giving uncertain positions with some fishy/wired corrections (e.g. your position history, phone triangulation and some assumptions on your mode of transports and your surroundings) while a certified GNSS will shutdown the whole thing (which is probably a good thing to get a safest outcome in TERM mode in IMC over terrain)
So for airspace busts on daylight in sunny days, I think this is a really good news irrespective of how many sats you see in orbit
(I view it as: does SatNav help me drive my car? can I use it in Nvidia driverless car software?)
LeSving wrote:
But, they also say to bring along paper maps as backup.
If the GPS receiver fails, most tablet nav software will function perfectly well as a map (and doesn’t need awkward cockpit origami exercises, and you can look up things like frequencies far easier with a long press on the VOR or airfield you want information on).
There is a company Tektronix producing, among others, precise sync pulse generators. The time base of the SPGs is synchronized by using GPS receivers.
Recently some of their units started behaving erraticaly, sometimes, somewhere.
They realized that Japan has launched satellites called Quasi-Zenith Satellite System. Signal of these satellites interferes with the GPS signal and can cause the GPS receiver to unlock. As these satellites are active only in some geographies (South East Asia, Australia, India), the problem was reported only there.
A firmware update of GPS receivers will sort it out.
More here
I wonder how does this interference affect the GPS navigation in the affected areas.
UK CAA says GPS is a Good Thing
At last. Better late than never!
