GPS Jamming
 

The CAA have published a Pink AIC detailing GPS Jamming Trials from Sennybridge.
The link is


http://www.nats-uk.ead-it.com/aip/cu...1_P_027_en.pdf

and they will measure and evaluate the results how exactly??

Are they going to have umpty GPS (from several different manufacturers) equipped aircraft flying round all the VORs in the area reporting on discrepancies or is this just a bunch of clowns playing with toys?:mad:

The CAA have been carrying out these jamming trials for some while now. Does anyone know what the purpose of these trials are? I just wonder if some one doesn't happen to be aware of these trials and an accident/incident is caused by them, who will be to blame?

It's the MoD that are carrying out the jamming, presumably testing some military kit.
The pilot should have read the NOTAM.

Even without any NOTAM, nobody is making promises on availability or accuracy or reliability of GPS.

It is there, it is usually working, when it is working it is great. Just don't count on it.

... and should be able to navigate successfully with reliance on a GPS. If the flight results in an accident because the pilot didn't have access to GPS then his abilitiies are below the PPL issue standard.

As GPS is not transmitted in a part of the frequency spectrum Internationally allocated for radio navigation, the MOD feel that the are free to play with it as they wish. Rather like Radio Caroline, GPS is a Pirate!

MY GPS is capable of PRNAV and BRNAV IFR navigation including approaches if these twerps would leave it alone!

Your GPS seems to be more that what the name promises. Actually it sounds like you have a navigation gizmo that takes information from several sources, including the GPS, and presents navigational info based on whatever it could get from its various sources. Nice - but be aware of the limitations.
Actually, what is it?

I don't think the reason for jamming the GPS signal is to prove it messes up your navigation. GPS is a military installation, we are lucky enough to benefit from.

I'm sure the purpose of jamming the signal is more likely to do with ideas such as if some nasty person figured they could easily guide some nasty device with a slightly hacked GPS to cause mayhem then it might be a good idea to be able to jam the signal to prevent it, no? :rolleyes:

It just proves again, that most people don't plan, and rely totally on GPS for nav. One day it's going to bite. Then again who reads NOTAMs? I was totally shocked at a recent safety day when several people when asked 'what is your current NOTAM solution' they shrugged shoulders and muttered things like, 'they are too complicated so I don't bother' or 'I ask someone else if they are about'. :ugh:

I'm totally shocked too! The AIS site has been so user unfriendly for years it's basically asking for infringements. Let's see how the SkyDemon initiative works out, it might just be the solution....

Don't hold your breath, it was at the NATS stand I overheard the above, though there was interest in the Skydemon solution, trust me the 'offenders' were the ones that were staring at it with glazed eyes and saying 'ooh that looks complicated' :hmm:

I think too it is a good initiative, though it will be the new to flying and younger pilots that will I think benefit the most. I personally simply bought and paid for the same sort of solution years ago, at least now I don't have to keep up my subscriptions.

Johnm... you sound like the sort of pilot I wouldn't like to be closer to than 100nm. Heck, you can't even spell your occupation right on your profile!

:):):):):):):)

HD, you may be retired but you haven't lost the edge.

It is true that there is a substantial UK GA sub-community which never checks notams (in most cases because they do not have internet skills) and I am sure they rarely check the weather too (unless BBC TV counts as a preflight briefing).

There is probably no short term solution to this. The problem is not helped by the 2-yearly flight with an instructor not (normally) being used to check preflight activities.

As regards reliance on GPS, I do wish some people got off their pedestals and accepted that WW1 ended in 1918 and WW2 ended in 1945, and times have moved on. Most people who go places seriously do fully use GPS and are not interested in jacking up their cockpit workload by timing each leg and identifying villages, lakes, railways, etc. The year is now 2011 and the establishment old-timers (members of the Royal Institute of Navigation, no doubt) need to realise that there are pilots who are flying modern planes, who go to real places not just around the corner, and if dead reckoning was the only way there would either be little or no long distance GA activity, or there would be mayhem. The really old timers in ATC did have to get a PPL originally but most of them rarely used it. There is also a large community in GA which never goes anywhere (probably the same people who never get notams) so they don't need advanced navigation, and can't see why anybody else should need it.

One normally backs up GPS with VOR/DME but at UK GA (sub Class A) altitudes there is often no navaid reception. And higher altitude flight around the UK (where navaid reception would be fine) is frustrated by the virtual inability to get an enroute clearance into Class A - another artefact of the tightly compartmented UK "airspace management system" which consigns VFR traffic (actually, more correctly, all traffic not on Eurocontrol IFR flight plans) into a low level dustbin.

BTW, every GPS is easily capable of BRNAV and PRNAV lateral accuracy. Getting the PRNAV approval is a whole another story.

WWII is over? Damn I wanted to move up to Spitfires :{

To be honest IO540 you are probably right, however as the CAA still say 'don't use GPS as primary nav' nobody should be surprised that it isn't protected in any way and can be jammed or even switched off.

I've never found keeping a plog difficult or particularly tiresome. Unfortunately it's the don't go far, don't read NOTAMs bunch who sometimes think a GPS solves everything. Can't use a VOR/DME and set out with nothing but a battery driven GPS which they barely understand. I know several who use a Garmin 12, yes a very useful unit for ramblers in it's time, hardly state of the art in an aircraft.

I can't say I've ever had VOR/DME reception problems at around 2500' if within the published range??

IO540, you trot out that old WW2 line every time someone on here suggests that pilots should be proficient at conventional nav techniques. As the laws of physics have not changed since the Second World War, then the techniques used for navigating aircraft back then still work just as well. These techniques remain part of the PPL and CPL syllabus and are assessed, so to suggest, as JXK did, that a GPS outage could reasonably cause an accident, and that somebody (presumably other than the pilot) would be to blame, is ridiculous.

It also shouldn't take too much imagination to guess why the MoD might be interested in a GPS jamming capability. Clue: every Tom, Dick and Ali in Iraq, Afghanistan, Libya etc can buy a handheld GPS receiver.:ugh:

I have to admit the only reason and I mean THE ONLY reason I still do a PLOG is because I dispensed with the damn whizz wheel at the beginning. I can just barely use the thing to pass exams and have an electronic flight calculator and software solutions. For me the PLOG and traditional Nav becomes a pleasure, simply because I have automated the calculations. It's then very nicely backed up by radio Nav aids and GPS.

So yes I totally agree, allow electronic flight calculators for those who prefer them and let traditional nav be simple. More people would use it I'm sure. People lose faith **in my experience** because of errors in the initial calculations using the whizz wheel. That thing really does belong in WWII. Basic vector sums based on forecast winds however remain totally relevant, particularly if they are easily and accurately calculated.

(and before someone says NASA used sliderules to get to the moon, they also had 6 people checking the results against each other because the things are so easily misread :ugh:)

funny old world isn't it. Apparently you are allowed to rely on GPS to stop you from going where you don't want to go (the Airspace Aware unit sponsored by NATS) but not to guide you where you do want to go.

Rans6...........

Even some of us who work on interesting hacks to publicly available electronic systems for security purposes are unlikely to know to what use our work is ultimately going to be put - the programmers get asked "please can you make it do x" and generally feel disinclined to ask "why?", a more appropriate response being "sure, when would you like it?". Personally I don't even think about it, I just do what I'm asked.

I rather thought the point was that you are NOT supposed to rely on it. Rather, it's a reminder in case your navigation skills are not perfect. (Whose are?)
Where did you get that idea?

All forms of navigation, including looking out of the window, fail from time to time. Pilots looking forward to a long and happy life do not rely on any one (except on a gin-clear day in familiar territory). Use GPS (most of us do), but keep a visual check on landmarks outside, or cross check with VOR/DME or whatever. Surely, assuming that something might fail is just good airmanship (and certainly part of IMC/IR training).

You don't know the MOD, if they say they are going to 'JAM' the signal, trust me that is exactly what they are going to do. ;) How they do it, well I would love to know but you can bet they are Jamming Exercises as stated in the AIC referenced in this thread and will be capable of messing up vehicle based GPS units within the stated range. It might occur to you that as the US DOD run the show the MOD might just like to make sure they can locally block the signal if the US DOD don't want to play ball one day.

In my experience, when GPS Jamming is taking place the GPS unit will alert to degraded or loss of signal. As long as you are aware of how to use your GPS properly.
A failure of the PPL is to ignore GPS completely, rather then properly explore the use and limitations of GPS. When you understand the limitations and errors, you are more confident to use it as the aid that it is.

SoCal App, thanks for the strange and ominous PM, life is all about making assumptions, but to indicate you really don't know much about the MOD despite your protest:



GPS Jammer Details
3.1 Omni and directional Jammer transmissions centred around 1176.45 MHz (L5), 12270.60 MHz (L2) & 1575.42 MHz (L1) will be
activated to potentially affect receivers tracking GPS signals.
3.2 Two graphic charts supplement this notification and represent the predicted coverage areas from high power and low power jammers
from which a GPS receiver is likely to encounter interference or blocking.
3.3 No allowance is made for airframe masking or the reduction of antenna gain towards the horizon seen in all receiver systems.
Therefore the worse case for receiver vulnerability is considered.
3.4 Low Power (max 10watt EIRP) Jammer coverage
10 ft agl - Areas with clear line of sight of the transmitter;
Up to 30000 ft - 75 nm radius from the transmitter sight.
3.5 High Power (100 watt EIRP) Jammer coverage
10 ft agl - Areas with clear line of sight of the transmitter;
10000 ft -120 nm from the transmitter pointing 220° True within an 80° Beam, less than 27 nm in other directions;
30000 ft - 180 nm from the transmitter centred on 220° True within a 40° beam, 108 nm within an 80° beam, less than 13 nm in other
directions.

If you had actually read the AIC quoted in this thread you would have realised that 'jamming' is not at all misleading. It is exactly what the MOD are going to do, they are going to transmit jamming signals :rolleyes:

I still do a full preflight plan and fly timed headings. However, because every silly little airport now demands a control zone, airspace is way too complicated..

Buying a Garmin 695 on Tuesday!

Well if your handle reflects your occupation you've happily worked me down L9 to DVR more than once :) Moreover I'm just checking NOTAMs for a trip home (airways as I write this). I can spell better than most and I have no idea what's in my profile, but I can easily correct it if it makes you happy :)

A very polite response to a unprovoked and totally unproductive attack.

I think that whilst GPS is an excellent tool, it should be remembered that it can be switched off at any point by the authorities. In the early days of GPS two standards existed, civilian and military. The civilian signal was degraded with an error which would be up to 100m, and the error changed every hour. Today we see accuracies of 300mm possible from civilian units.

I can totally understand the reason and need for a jamming unit, all that would do is disrupt the signal from the GPS satellite to the GPS unit making the GPS unusable in the area covered by the jamming transmitter. It’s not rocket science, any radio ham could potentially make one. It would not be legal, but technically not difficult.

The need for a jammer? That’s easy, if we do a Google search for UAV autopilot then it’s easy to find both ready made GPS guided autopilots units for UAV’s (which in their simplest form are model aeroplanes) and build your own unit designs. Now imagine the scenario, somewhere sensitive, or a sensitive event, someone has one of these units (GPS guided device) and its used to position a model aeroplane loaded with something nasty to within a meter of where the person wants it to go.... It becomes a very easily available guided weapon.

I think we have to accept that we live in a very unstable world, that we have no right to GPS services (in fact the use of it should be looked on as a privilege rather than a right) and that the use of it can be removed without notice. WE all need to go back to basics, and remember that GPS can fail, get jammed or be switched off without notice.

Which is why one should avoid relying on any single source of navigation information.

As IO540 says why should a GPS be a privilidge? Why do we accept so many things from "authorities" as a privilidge and not a right we have earned? Is it the "establishment" trying to keep the peasants in their place? Is your drivers licence described in the same way as your Pilot's licence - i.e. "to exercise the privilidges etc"? Can you imagine the outcry if drivers licences were so worded.

One absolute right we all have in English law is to spell privilege correctly, or not, as we choose.

The reason that we dont live in caves is because we evolved. That’s the same for all technologies. How much payload do you need to cause havoc - its all about the potential to do it and stopping it before it ever happened? A navaid will get you to a point, a known point which is pre defined. A GPS unit will get you to ANY point that someone wants.

Don’t underestimate model aeroplanes, they can come in a range of sizes. Have a look at LMA on Google if your not sure.
I quote below from one UAV autopilots website, surely its easy to see the potential threat from such a unit and the reason that a jamming unit is needed. Its got to be better than switching off all the signals...

• Small size without sacrificing functionality; 28 grams, 4 cm by 10 cm
• GPS waypoint navigation with altitude and airspeed hold
• Completely independent operation including autonomous takeoff, bungee launch, hand launch and landing
• Powerful script language command set
• Open architecture – all state fields fully accessible
• Fully integrated with 3-axis gyros & accelerometers, GPS, pressure altimeter, pressure airspeed sensors, all on a single circuit board
• Extensive data logging and telemetry capabilities
• UAV configuration wizard and installation video simplify installation

I’ve never known a group bang about rights the way pilots do.

You have the right to use GPS. Really, you do. Happy now?

The US government has the right to switch it off, and the MoD have the right to jam it. Where does that put your right? You don’t have the right to stop them, and you probably don’t have the right to action against them nor compensation from them if that happens.

You also have the right to exercise airmanship, which might include identifying single point failures that might impose hazards on the flight.

Staying alive, on the other hand, is not a right but a privilege.

Gosh FREDAcheck, I wish I was as clever as you, how wonderful it must be to actually know you personally.

Why on earth would you assume I think it is a big deal. I was simply correcting your misinformation that the term 'jamming' was misleading when it is not at all.

You mean: I wish I were as clever as you.

Don't overdo your show, FREDA. Twas nice as it was.

Sorry, I couldn't resist. But I meant what I said: we each do have the right to use English how we please, even if pedants like me point out that it's not the way an English teacher might teach it.

Looks like it's not only the aviation community that's worried by GPS jamming.

Military jamming of GPS in Scotland suspended.