Primarily for general aviation discussion, but other aviation topics are also welcome.
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By Shoestring Flyer
#1846314
johnm wrote:Thanks to less medieval aspects of this debate I think I now have a way forward.

I am going to persevere with SE2 for the time being and experiment with different positioning. I am going to monitor CS-Stan update and assuming that comes through next year I'll suggest to the group we replace the old ELT infrastructure in our aeroplane with PowerFLARM fusion.


Sounds like a sensible plan.... :D
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By Marvin
#1846333
johnm wrote:Thanks to less medieval aspects of this debate I think I now have a way forward.

I am going to persevere with SE2 for the time being and experiment with different positioning. I am going to monitor CS-Stan update and assuming that comes through next year I'll suggest to the group we replace the old ELT infrastructure in our aeroplane with PowerFLARM fusion.


Can you not this or has it not been transferred across on exit of EASA?

https://flarm.com/shop/easa-minor-chang ... rm-fusion/
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By gaznav
#1846337
riverrock wrote:So has the range been tested?
70W = 10nm (18.5km)
20W = 2.9nm ?
I assume that's too simplistic?

Vector with its larger antenna can pick up further, but that isn't representative of air to air.


As far as I understand it, the Class A0 has a minimum performance standard of 10nm in transmit and receive against at least another A0 device. That is really important to understand. I have certainly detected another CAP1391 standard SkyEcho 2 with my own SkyEcho2 at 10nm - I was in a Condor and the other aircraft was a Steen Skybolt. But the thing is, at maximum range I could see the Skybolt intermittently at around 20nm and the closer it got, the more I saw it more of the time. By the time it got to around 10nm then the detection was pretty solid.

I also understand that Class A0 does not consider the installation - so effectively it is 2 units with their antennae, plain and simple, that need to be able to 100% detect each other from all aspects at 10nm. It would be interesting to conduct the exercise with 2x SkyEchoes radiating at 20W (or is it 25W - there is a discrepancy in that specification between the uAvionix documentation) to see whether it can meet that. Maybe something to try and do in the UK with 2 devices 10nm apart on hill tops? Remembering that the VSo needs to be set to zero.

As for 20W SkyEcho2 being guaranteed for reception at 3nm to aid see-and-avoid? I’ll take that, as I can’t see most GA types outside of that sort of range on most days. Although, I suspect that a high probability of detection is higher at around 10nm between similarly equipped aircraft from my own experience.
By johnm
FLYER Club Member  FLYER Club Member
#1846338
I assume that all that has been carried over but i’d need to check with CAA and if I wait for CAA to release the CS Stan I don’t have to pay anything or spend hours on the phone trying to understand how EASA MCA is implemented under CAA rules.
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By gaznav
#1846351
Just to put the above post on power into perspective then have a read of this slide pack looking at very low power ADS-B for drones at 0.1W and 1W: https://www.icao.int/MID/Documents/2019 ... 090MHz.pdf

I guess that EUROCONTROL have been doing their own modelling in light of some of the wild claims about 1090Mhz frequency when using lower power devices (those claims are untrue from my own viewpoint, and it is the 70W, 125W and 400W-500W transponders that cause the issues).

They predict a 98.5% probability of detection of a 0.1W ADS-B signal over a 5 second period (in an environment of 3 other small drones operating within a km of each other near either Charles De Gaulle Airport or Frankfurt Airport with lots of transmissions on 1090Mhz) - that range was 0.8nm for guaranteed detection in the worst case scenario. For the 1W ADS-B signal in a similar environment that guaranteed detection was 2.3nm. The snag being that if there many drones all equipped with 1W then the modelling predicted a reduction of all other ADS-B signals by 41%, whereas the 0.1W saw a very small reduction of less than 8%.

So, on the basis of that, I would offer that very low power ADS-B for small drones (2-25kg in mass) using 0.1W would be ok if you could guarantee getting a warning by roughly 1 mile from it, and a 50% likelihood of detection at 3-4nm (interpolating from the graphs).

Obviously, for 20W then SkyEcho would significantly improve on those ranges - 70W shows about 21nm for 98.5% and 1W is 2.3nm, so if we take a broadly linear relation then 20W would be around 6nm for guaranteed reception between aircraft when the 1090Mhz frequency is at peak use. Again, I’ll accept that for what it is if any aircraft is going to detect mine at 6nm.

But [health warning] there is a bit of interpretation in my final conclusion. :thumright:
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By Straight Level
#1846377
gaznav wrote:Just to put the above post on power into perspective then have a read of this slide pack looking at very low power ADS-B for drones at 0.1W and 1W: https://www.icao.int/MID/Documents/2019 ... 090MHz.pdf

I guess that EUROCONTROL have been doing their own modelling in light of some of the wild claims about 1090Mhz frequency when using lower power devices (those claims are untrue from my own viewpoint, and it is the 70W, 125W and 400W-500W transponders that cause the issues).

They predict a 98.5% probability of detection of a 0.1W ADS-B signal over a 5 second period (in an environment of 3 other small drones operating within a km of each other near either Charles De Gaulle Airport or Frankfurt Airport with lots of transmissions on 1090Mhz) - that range was 0.8nm for guaranteed detection in the worst case scenario. For the 1W ADS-B signal in a similar environment that guaranteed detection was 2.3nm. The snag being that if there many drones all equipped with 1W then the modelling predicted a reduction of all other ADS-B signals by 41%, whereas the 0.1W saw a very small reduction of less than 8%.

So, on the basis of that, I would offer that very low power ADS-B for small drones (2-25kg in mass) using 0.1W would be ok if you could guarantee getting a warning by roughly 1 mile from it, and a 50% likelihood of detection at 3-4nm (interpolating from the graphs).

Obviously, for 20W then SkyEcho would significantly improve on those ranges - 70W shows about 21nm for 98.5% and 1W is 2.3nm, so if we take a broadly linear relation then 20W would be around 6nm for guaranteed reception between aircraft when the 1090Mhz frequency is at peak use. Again, I’ll accept that for what it is if any aircraft is going to detect mine at 6nm.

But [health warning] there is a bit of interpretation in my final conclusion. :thumright:


One critical omission in making your conclusion @gaznav .

The test had a ground based antenna and the drone antenna (I didn't read all the report) would be in free space without fuselage, big bag of water or wings to block the signal.

So potentially two SE2 units with a wing or body etc blocking the signal path (possibly at both ends or the link), then even 20w might not be enough at even short ranges.

It will be a good day when I can pop a couple of holes in the ole spam can and mount the antennas out in the fresh air without needing to spend more on the STC paperwork than all the kit combined. :thumleft:
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By riverrock
FLYER Club Member  FLYER Club Member
#1846408
gaznav wrote:Just to put the above post on power into perspective then have a read of this slide pack looking at very low power ADS-B for drones at 0.1W and 1W: https://www.icao.int/MID/Documents/2019 ... 090MHz.pdf


Certainly an interesting mathematical study.
Obviously, SE England pre Covid had much higher CAT density with their high power transponders, the study assumes perfect reception with the antenna and it only considered drones detecting other drones in an environment with CAT flooding the frequency.
How much warning would be the minimum to have a drone dead ahead? If you travel at 100kts, their main scenario would mean 80seconds warning (to detect, pilot to notice & understand, form an avoidance plan, execute plan). A jet doing a low level sortie at 600kts would have 16 seconds - assuming perfect reception. Enough?
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By ls8pilot
#1846444
riverrock wrote:
gaznav wrote:Just to put the above post on power into perspective then have a read of this slide pack looking at very low power ADS-B for drones at 0.1W and 1W: https://www.icao.int/MID/Documents/2019 ... 090MHz.pdf


Certainly an interesting mathematical study.
Obviously, SE England pre Covid had much higher CAT density with their high power transponders, the study assumes perfect reception with the antenna and it only considered drones detecting other drones in an environment with CAT flooding the frequency.
How much warning would be the minimum to have a drone dead ahead? If you travel at 100kts, their main scenario would mean 80seconds warning (to detect, pilot to notice & understand, form an avoidance plan, execute plan). A jet doing a low level sortie at 600kts would have 16 seconds - assuming perfect reception. Enough?


As I understand it the plan is not for the aircraft to avoid the drone - unlikely to get visual acquisition & just too difficult I suspect. The Drone will(should) have "Detect and Avoid" software that will cause it to automatically take action if other traffic approaches - for example it could drop to 20 ft or land ? For larger Drones there is already available software like this which works off camera data. Maybe someone knows a bit more - I've only done some sketchy reading.
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By Forfoxake
FLYER Club Member  FLYER Club Member
#1846455
johnm wrote:@Shoestring Flyer Doh :roll: I hadn't twigged that Powerflarm received ADS-B and Mode S it starts to look like a no brainer..... :roll:


That's why I have been using PowerFLARM portable for about 5 years. However, I added PilotAware about 2 years ago because many of the microlights at my home base were using it. Finally, very recently, I added SE2 (transmitting only) and claimed the CAA rebate. I also have a Mode C transponder!

I know it is not air to air, but Vector indicates very little difference between FLARM and PAW detection but much poorer ADS-B detection so far despite placing the set in different parts of the (metal tube) cockpit. Imho, SE2 would benefit from an external antenna connection (external to the set, like PowerFLARM, not necessarily to the airframe).
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By Marvin
#1846474
From the latest IAOPA News letter, sorry for the long post:

Since aviation began its expansion, one of the greatest risks has always been an in-flight collision. Larger machines are required to have advanced anti-collision systems on board. This obligation does not apply to smaller GA traffic. The cost of advanced systems cannot be met by a private pilot.
The responsibility for collision avoidance lies partly with ATC and partly with the pilot who, without technical support, still relies on "see and avoid" techniques to avoid collisions.

There is a clear danger for all categories of aircraft flying in the same parts of restricted airspace, especially around regional and national airports and aerodromes. The number of accidents and near misses on an annual basis, were sufficient for the European Commission to give EASA a mandate to take mitigating action. This led to the EPAS (European Plan for Aviation Safety) in which new technologies were described to reduce collision risks.

Large, expensive, complex and heavy systems cannot be applied in the GA fleet, however, the technology needed to avoid these risks already exists and follows an international technical aviation standard already used by all aircraft in the US and other parts of the world, to the satisfaction of ATC and the pilots. This technology is fully compatible with the systems used in larger aircraft and fully compliant with current regulations.

Weather and anti-collision data available to all airspace users is not part of a futuristic Sci-Fi scenario. The technology is just sitting on the shelf. Recent studies show that the number of airproxes in the US has been reduced by 53% through the use of these techniques. The risk of a collision with fatal consequences has even been reduced by 89%!

For the GA fleet, the investment per aircraft is relatively small. If the pilots realise that they will benefit from the purchase of this kind of equipment, they will be more willing to invest, especially if the government (like in the United Kingdom) is prepared to lend a hand and sets up a subsidy scheme that will improve air safety by leaps and bounds.

IAOPA’s position

In order to reduce the risk of collision once and for all, IAOPA urges the European Commission and EASA to implement the already existing standard using two different frequencies so that the number of collisions and especially the number of fatalities resulting from these collisions can be seriously reduced. By increasing situational awareness among pilots, controllers and AFISOs, Dual Band ADS-B becomes one of the most important tools to increase flight safety at a very acceptable investment. By installing ground stations at GA airports, among others, AFISOs will have additional tools to safely handle traffic in the vicinity of the airport. At the same time, a European network is being set up to improve flight safety.

IAOPA together with the companies that started the US ADS-B infrastructure and the companies within Europe that are working to make the airspace safer, recommend Europe to build a network of ground stations that, using the ADS-B protocol and dual frequencies (1090 and 978 MHz), will bring tangible and immediate benefits to all airspace users. This should make use of existing, "off the shelf" solutions. IAOPA believes that the use of a unique system across Europe is the only way to increase safety for all airspace users.
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By Dave W
FLYER Club Member  FLYER Club Member
#1846476
That's sensible, and an ADS-B dual band ground network would indeed be an incentive.

"Unique" in the final sentence doesn't feel the right word, though, and I wasn't sure what they mean. A network of standardised technology and operating regs (with local add-ons where appropriate) across the World would seem a worthwhile aspiration.
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By ls8pilot
#1846496
Here is an example of Flarm / Drone integration - in this case (somewhat scarily IMHO) being used to formation fly two Drones and TMG !

https://www.team-blacksheep.com/products/prod:flarm_aviation



This is an example of how commercial implementations can & will leap ahead, while endless standards committees are still debating which frequency to use and civil servants and Govt agencies try to decide whether to write ADSB, ADS-B or ADS/B, we will find this is all up and running in Europe........ :lol:
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By Peter Gristwood
FLYER Club Member  FLYER Club Member
#1846503
So not programmed to stay away from another light aircraft, but to formate on it and miss it by not very much. New definition of sense and avoid?

Hmm
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By ls8pilot
#1846504
Peter Gristwood wrote:So not programmed to stay away from another light aircraft, but to formate on it and miss it by not very much. New definition of sense and avoid?

Hmm


I have a vague feeling that maybe the scenario shown is not quite what the CAA had in mind ? :shock: :lol:
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By gaznav
#1846527
A jet doing a low level sortie at 600kts would have 16 seconds - assuming perfect reception


Just for the record, the top speed allowable overland these days 540KIAS IP to Target, and 480KIAS Max otherwise. Most jets in the low flying system stooge around at 420KIAS. :thumright:
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