Jamming UAVs

One of the downsides of UAV is .. unless they are autonomous... is the potentional of enemyies being able to jam, or disrupt transmisions to and from the craft. Is this a possibility? or are the counter-measures in place

Yes this would be where most counter UAV/UCAV depts. would concentrate..
However are UAVs aside, are UCAVs going to be remote controlled or preprogrammed with 'skynet' like AI before launch itself?..
If preprogrammed then it would be difficult to acquire control..

The X-45 is the first of the next generation UAV's, it will fly autonomously because its mission programmed in the computer onboard.

I thought they were controlled via a sattelite network? Making it pretty hard to jam, innit?

Originally posted by Aelita
I thought they were controlled via a sattelite network? Making it pretty hard to jam, innit?

I think they navigate using satellites (GPS)..
They poll the satellites, not vice versa..

As mentioned before most UAV's fly with a onboard computer. Depending on the type of UAV and it's mission.. Most are preprogrammed and sent on their way. They poll GPS satellites and fly to their waypoints, carry out their mission, and return to the home waypoint. You could also change the flight by reprogramming the route.

Just think of it as going on mapblast, getting instructions on how to go to a friends, Stop at 7-11, the mall, and McDonalds. You then program those points into your GPS in your car. Then you forget you have to drop a package off and reprogram the GPS to take you to the post office.

Back to the topic... Depending on the UAV the easiest way stray one would be to Jam GPS. You could probably take out a few Civilian UAV's, but I'm not sure about military grade.



[edit on 6-5-2005 by typicalaimster]

The Jamming problem would be for any realtime attacks such as UCAVs designed for attack armoured targets, fighter UCAVs and other non static target bombing UCAVs.

[edit on 6-5-2005 by COWlan]

Originally posted by Daedalus3

Originally posted by Aelita
I thought they were controlled via a sattelite network? Making it pretty hard to jam, innit?

I think they navigate using satellites (GPS)..
They poll the satellites, not vice versa..

GPS sats send out a continuous signal, and the receiver reads those signals when it wants, does the necessary calculations and determines where it is. GPS signals are notoriously easy to block - give me any GPS receiver in the world and I can block it with a few household items. My computer networks WiFi hotspot interferes with both my GPS receivers (3 year old and 6 month old) and my dads military one enough so that none of the units can gain a triangulating signal.

Originally posted by RichardPrice
give me any GPS receiver in the world and I can block it with a few household items. My computer networks WiFi hotspot interferes with both my GPS receivers (3 year old and 6 month old) and my dads military one enough so at none of the units can gain a triangulating signal.

lol yea....right...to bad GPS is NOT an auto. system anymore....

Originally posted by Aether
lol yea....right...to bad GPS is NOT an auto. system anymore....

What do you mean?

Some GPS info to explain and backup my previous post:

Receivers get a signal from a satellite which contains a unique Satellite ID, time signal sent and some other technical data called a psuedo random code. The receiving unit has a set of data in it which tells it where all the GPS satellites are at any given time on any day ever. Minor positioning error corrections are sent with the GPS signal.

Receiver measures time difference between sending and receiving (travel time), calculates the distance from the satellite to itself, while keeping the receiver and sender clocks in sync is a function of the psuedo random code signal. The psuedo random code does a lot more, like allow for amplification of the signal with very small antenna, and ensure that each satellites signal is unique and doesnt block each other. The satellites have atomic clocks on board, and the receivers can reset their own clocks based on each satellites time reading, ensureing that the receiver is in sync.

This gives it a possible number of locations on the earth it can be based on the distance from that satellite, which works out to a sphere the radius of that distance. Do this with more satellites to cut down on the possible locations by intersecting the spheres calculated for each satellite, you are whereever those spheres intersect. The more satellites you can receive a signal from, the smaller that area becomes, and also the longer you spend receiving signals from the same satellite, the smaller the area becomes, which is why if you leave a GPS receiver for a period of time, it keeps increasing in accuracy over that time.

In general, it takes 3 satellites to give you two possible locations for your receiver. Why two? Because thats where the third satellites sphere intersects the other two satellites spheres based on how the measurements are done. You can wait for a fourth satellite to come into view to be able to determine 100% which of those two points you are actually at, but in reality one of those two points nearly always is 'impossible', ie its not on Earth (IE its in orbit or further out), or that points velocity based on updates from the satellite is far too high for it to be you. A fourth satellite is also needed when your GPS receivers clock is out of sync with the satellites clocks - 3 satellites give you a rough area and the fourth satellites measurement gives you enough information to reset the receivers clocks and recalculate its position with the new accurate time reading.

So in points:

1. You need distance measurements from the satellite to you
2. You need 4 satellites to guarantee a 100% accurate location
3. In general only 3 satellites are required because most of the possibilities are rediculous or impossible
4. A 4th satellite can give you speed and altitude measurements, allowing for aircraft navigation, as well as correcting timing issues

A new update to the GPS system called the Differential GPS system allows for ground based GPS transmitters, which give GPS a huge accuracy boost (down to centimeters). Basically ground units all around the world receive GPS signals from space and can work out the errors in the signal based on atmospheric issues, and send out correcting signals as GPS signal updates, so receiving units can calculate with a much greater accuracy. This is why the US DoD removed the Selective Availability error that was inherent in all GPS signals up until 1997, because new Differential GPS systems even remove that deliberate error, so the signal is pretty much as accurate as it can get.

Jamming GPS signals is actually pretty easy, a private Russian firm called Aviconversias announced in 1997 a product that could effectively render all GPS receivers in a 200km radius useless, even with standard and DGPS error correction applied. In December 1997, military testing of a similiar system near New York caused a large number of civil airline GPS receivers to fail and complaints to be put forward by the FAA. GPS signals are very very weak anyway, just going into a building, or under tree cover is sometimes enough to stop a unit getting a fix, and blanketing the GPS frequency with random noise can disturb a signal enough that error correction is useless, although this only works for very close receivers, up to several metres. This is why GPS is required to have a working, reliable backup system when installed in civil airliners.

There are anti-jam GPS receivers that cost many thousands of pounds, but they arent effective against all jammers and its fairly trivial to block consumer receivers or military receivers older than around 2002, for example take some tin foil and put it over the GPS receivers antenna. Tin foil is only a few hundredths of a mm thick, yet thats enough in nearly all cases to block a GPS signal. The main problem with military jamming is that it makes the jammers very easy to track and destroy with antiradiation missiles.

www.avweb.com...
www.gpsworld.com...
www.raytheon.com...

There are indeed of tech deviced that can actually work jamming gps signals and the wireless network. The accessibility of the devices does post quite a danger the stability of craft projects.