European made onboard, fixed wing AEW.

Unpressurized …

I believe so……….of course that doesn’t mean it couldn’t in a AEW Type Model.

I believe the V-22 Osprey has a ceiling of 22,000 ft………..just for comparison purposes.

Unpressurized …

Service ceiling for Defender is 25,000. Sea King is 12,000. The new Defender is a bigger and more powerful beastie than the original one looked at back in the early eighties.

I believe the V-22 Osprey has a ceiling of 22,000 ft………..just for comparison purposes.

If they want to fly that high then given that these will have a long loiter time then something pressurised would really be the answer.

Not sure it can fly high enough for sensible coverage compared to a helicopter. Maybe just a little too cheap and cheerful solution even for a cash strapped MOD

Service ceiling for Defender is 25,000. Sea King is 12,000. The new Defender is a bigger and more powerful beastie than the original one looked at back in the early eighties.

Not sure it can fly high enough for sensible coverage compared to a helicopter. Maybe just a little too cheap and cheerful solution even for a cash strapped MOD

Islander Defender for AEW? It was talked about when the Invincibles entered service as an alternative to the Sea King conversion.

Line drawings of the Hawker Siddeley P.139B. The AEW version (note the radar domes fore and aft) is shown in most of the views, but the freighter version is shown in the right mid profile.

A carrier capable version of the Hawker Siddeley HS.125 Dominie was considered for Carrier on Board Delivery tasks.

http://navy-matters.beedall.com/cva01.htm

I did read recently that the P.139B would have been unflyable and at best a widow maker (not that that mattered to the RN of the 1960s!). If CVA01 had been built its almost enivitable that AEW would have been Gannets and then Hawkeyes when they ran out of hours.

As a though wouldn’t the Domonie have made a cracking little ASW platform, a British Viking…..?

The RN’s NEST project is down to give AEHF to the CVS’s and two SGS’s.

Skynet 5 is more capable than you are assuming. There are IIRC 8 20Mhz channels plus a couple more 36Mhz bandwidth and a couple more at 40Mhz. Those are not there for a couple of fiddling little kbps range circuits. They have other narrowband channels configured for that.

I do not doubt that Skynet 5 is a very capable constellation. It sure must show that it’s quite younger than Milsat II.
What you are referring to is the SHF band (LDR).

Here is a link
http://geopolmedia.free.fr/defense/Europe%20Satellites/satcom.html
saying Syracuse III has only 2/3 EHF spots with 6 channels (which is NOT a lot). But again no word on Skynet 5 EHF.

Would the EDRS (European data relay system) SAT’s have any effect on all this?

apologies I’m not much of a sat com geek:o

Nevermind, this PDF seems to indicate it will have some role in that area.
http://esamultimedia.esa.int/docs/MinisterialCouncil/MC-EDRS_1811.pdf

The RN’s NEST project is down to give AEHF to the CVS’s and two SGS’s.

Skynet 5 is more capable than you are assuming. There are IIRC 8 20Mhz channels plus a couple more 36Mhz bandwidth and a couple more at 40Mhz. Those are not there for a couple of fiddling little kbps range circuits. They have other narrowband channels configured for that.

Would the EDRS (European data relay system) SAT’s have any effect on all this?

apologies I’m not much of a sat com geek:o

Should be feasible to use one UAV as a comms relay for others, extending line of sight range considerably. With a largely autonomous UAV, there’d be little additional operator load. Just park it in a tight orbit at maximum altitude, & leave it be for the rest of the day, until it’s time to tell it to come home. Perhaps an unloadable comms package, so that you don’t need a dedicated UAV for the purpose, but can hang the comms package on one whenever satellite links aren’t available, or are needed for something higher priority.

Re the Skynet 5 MDR capacity: What is known is there are 4 spots. What I do not known is how many EHF uplink channels there are per spot; for UHF they say 9. On the French sats public info says 9 EHF. 1.5 x 9 x 4 = 54Mbit/s would make sense, but is pure speculation since what is out there in public domain is too fuzzy and EADS Astrium is not very forthcoming with info about their MDR capability.

Skynet is not XDR capable (“dozen channels capable of 10Mbps data transmission or higher”), that would have gone up with AEHF and TSAT the first time. Before everything came apart in the U.S. MILSATCOM game the plans were having Gbit/s bird up by 2015 – not gonna happen.
Each Iridium sat for example has 48 spots (whereby only 16 look at you; plus four spots for 10Mbit/s orbital crosslinks) with 10 3.8kbit/s duplex channels with 4 slots per channel. Iridium could in theory give a superuser a 600kbit/s link per satellite :D.

I have no real idea what the data rate uplink requirement for a radar would be. Compression is a given. For a weather radar in clear air that results in around 800kbit/s. In a busy airspace it depends on the extent of onboard processing capability, especially when operating in a ECM environment. What’s the neccessary computing power for that, what volume, weight, power. cooling? If you use just a raw uplink, simple noise jamming could easily lead to an uplink overflow. Is it better to put more stuff onto the UAV, or give the uplink a higher thruput? The uplink itself shouldn’t be terribly vulnerable when using an AESA pencil beam antenna and fancy waveforms. Jamming the satellite itself is more difficult, and I think Skynet 5 has at least one nulling antennas.

In 2000 they tested a Global Hawk in such a more-or-less raw uplink scenario and used a TCDL with 10.7Mbit/s. It’s that number that lead me to my “one spot per Radar-Mantis” statement. A spot seems to have a typical EHF aperture of around 3 degrees, something that has to be kept in mind when getting data uplinks from UAVs far off other “subscribers”.

Edit: http://www.californiaspaceauthority.org/images/pdfs/040831-milsatcom-anderson.pdf
From more optimistic times.

The question is what would the required data rate be for a AEW radar uplink? I guess the lower end of TCDL.

To compare: The JSTARS’ SCDL has 1.9Mbit/s for *processed* user data. TCDL UAV command link has 200kbit/s, the return data link uses between 10Mbit/s and 45Mbit/s. The Common High Bandwidth Data Link standard used for “global persistant ISR” has up to 274Mbit/s.

A Skynet 5 with 4×9(?) MDR channels gives a total combined data rate of no more than what Wi-Fi gives you on your notebook, meaning one spot for one Radar-Mantis.

As I understand Skynet 5B is doing good business with the U.S. forces in south-west Asia. Any idea why they chose to park 5C in a spot that is way off any intersting area, even if they say it’s spare? Relocating him 60 or more degrees eastwards will cost quite some fuel.

I think you are under-estimating the throughput potential of the Skynet platforms. From a quick scan there are at least a dozen channels capable of 10Mbps data transmission or higher – and thats just whats been identified by amateurs with RF spectrum analysers!. 8PSK tx’s capable up to STM-1/OC3 speeds are advertised commercially so 10Mbps transponders are anything but unusual.

Obviously the bandwidth requirement for streaming radar data is going to exceed the 200kbps signalling channel required for platform control. Like you say though it cant get close to the requirements for video transmission. I would make the estimate of some multiple of the 2Mb downlink from the J-STARS stopping short of the entry point into the current UAV downlink range. It is possible also, particularly with raw statistical data such as a radar feed, to implement compression and acceleration techniques to minimise bandwidth utilisation.

I think you would be looking at a good few more simultaneous UAV downlinks than just the one. With low subscriber load, i.e prior to Army/RAF lodgement in theatre, we could see half a dozen simultaneous feeds with relative comfort. Even with an established subscriber base to support you would still expect 3-4 which, with UAV’s supporting fleet ops as described by Swerve using air-relay or direct-path LoS back to the ships, would be quite sufficient for the kinds of operations we would be able to mount.

As to 5C its parked somewhere in the median of the two operating birds so it can be positioned to cover either relatively quickly in event of a fail. It would use a significant quantity of fuel to re-position I agree, but, once positioned there shouldnt be much call to move it again. Presumably if we used the reserve it would be replaced by converting the option for the 4th unit into a build.

The question is what would the required data rate be for a AEW radar uplink? I guess the lower end of TCDL.

To compare: The JSTARS’ SCDL has 1.9Mbit/s for *processed* user data. TCDL UAV command link has 200kbit/s, the return data link uses between 10Mbit/s and 45Mbit/s. The Common High Bandwidth Data Link standard used for “global persistant ISR” has up to 274Mbit/s.

A Skynet 5 with 4×9(?) MDR channels gives a total combined data rate of no more than what Wi-Fi gives you on your notebook, meaning one spot for one Radar-Mantis.

As I understand Skynet 5B is doing good business with the U.S. forces in south-west Asia. Any idea why they chose to park 5C in a spot that is way off any intersting area, even if they say it’s spare? Relocating him 60 or more degrees eastwards will cost quite some fuel.
Not sure if the French rent out their capability.

And none of this is relevant if we’re using airborne relay.

The BAe way (according to what Flight & JDW have reported) is not to use satcoms from the other side of the world, but local control, & a very high degree of autonomy. The UAV flies itself. The operator watches – perhaps more than one UAV at a time – and only intervenes if required. That means very few signals going from operator to UAV.

This seems to be designed for armed forces which do not necessarily have global satellite networks to call on.

I would expect an operator on board ship, or on the AEW helicopter, to control a Sea Mantis. If it was on AEW duties, it would require very little input, perhaps none, just flying regular orbits, shifting to keep up with the ship.

Dont forget though Distiller the load on those sats is relatively modest compared to the number of subscribers that participate in the US satcom environment.

The new Reacher Med terminals the Army has in the field are only 2Mbps links – Reacher-L can do E2 speeds but there are only 6 terminals last I heard!. SCOT-5 doesnt step up that much and, obviously, with the decline in escort numbers there is a decline in terminals in any particular theatre.

The number of UAV’s we would be deploying in theatre, even in a mythical Sea Mantis equipped future, would be modest to the extent you would be pushed to see bandwidth requirements to support more than, perhaps, 6-8 UAV’s operating simultaneously relying exclusively on satcoms. Granted that throughput to support that kind of streaming data is significant but there really wont be too many dataflows to contend with.

Then there is the observation that there is extra capability built into the Skynet 5 system with the 5C bird. It is listed as an in-orbit spare, but, its also an in-orbit augmentation capability at the issue of a suitably-sized purchase order. Where the need to provide additional channels to arise the only delay in its provision would be the Treasury-lag and the time required to re-position the satellite.

France, the UK, Italy and Germany together will operate 12 military communications satellites by the end of the year (3 Syracuse-3, 2 Syracuse-2 dual-use, 3 Skynet, 2 Sicral, 2 SatComBw), and could reaquire another 8 sats relegated to commercial civilian secure comms without too many problems quickly (6 Skynet-4, 2 NATO-IV).

Now it gets tricky!

What you are looking for if you want to do UAV stuff is (protected) medium data rate capability.

There are not a lot of satellites providing that. The U.S. Milstar II (4, 5, 6) for example.

The Europeans have six sats up there currently that qualify. Skynet 5A/B/C, Syracuse IIIA/B, SICRAL 1B.

Thing is that their coverage is limited to about 100 west – 120 east, and if you look closer you’ll see that only 2 of them (Skynet 5B and Syracuse IIIA) are far enough east to be of use for operations in “East of Aden”, the other dispy-doodle around over the Gulf of Guinea (don’t ask me why they put them all there!). The Milstars are spread out around the globe (though one is missing, which is somewhat compensated by a slow drift of the formation).

The number of the Skynet & Syracuse MDR spots/channels is also not really that high. Those two European eastern sats combined seem to have around one third of the capability of a single Milstar II.

(and if not it’s getting real complicated with airborne or orbital relays – neither of which the Europeans really have)

France, the UK, Italy and Germany together will operate 12 military communications satellites by the end of the year (3 Syracuse-3, 2 Syracuse-2 dual-use, 3 Skynet, 2 Sicral, 2 SatComBw), and could reaquire another 8 sats relegated to commercial civilian secure comms without too many problems quickly (6 Skynet-4, 2 NATO-IV).