Re: [Drip] ADSB

[Alexandre Petrescu <[e-mail]>]

Le 12/07/2023 à 17:31, Robert Moskowitz a écrit :
> 
> 
> On 7/12/23 11:13, Alexandre Petrescu wrote:
>> thanks for the clarification I must have endeavoured in
>> unchartered lands...
>> 
>> Just to clarify: I am not disputing.
>> 
>> I came with this thread to say that I saw ADS-B drones on 
>> flightradar.
> 
> I am sure people do it.  How they get an aircraft number might be 
> interesting.  Of course some transponders are preset for this from 
> what I have heard.
> 
> Also I am away of code that takes "standard" Remote ID messages and 
> feeds that into ADS-B systems.  So you see them in things like 
> FlightAware, but they are NOT sending ADS-B.

Interesting.  If so then flightradar might say so somewhere on the
Internet.

> of course you have to lie about the aircraft number,

For the aircraft type, registration and country of reg.: it says 'N/A'.
(for 'Not Available' I suppose - never knew what a dash had to do there,
as if it were 'Not/Available').

There is no 'aircraft number' in the page, but maybe you meant something
like that.

Also, even the legally carrying ADS-B aircraft sometimes dont provide
some of these ADS-B fields, or are some times badly read, or badly
interpreted.

But I am happy to see what is there to be seen.

> going from the 20 character UA ID to the 24-bit aircraft number...

The 'ADS-B' drone I saw on flightradar said the 'ICAO 24-bit address'
was '511161' decimal I suppose.  Is there a means to check the validity
of this number?  Or to tilt to thinking it is a fake?

> The one effort I reviewed on this I asked this question, and they 
> said the hashed the UA ID down to 24 bits...

Sure, we can do anything, put random or other crazy things in there -
but maybe it is not very good to play like that with these numbers.  But
I will not dispute that either.  I am just happy I could see it there.

If they hashed the UA ID to 24 bit for a 'standard' Remote ID of a drone
into ADS-B - would they do the same for a ground vehicle at the airport?
  Do ground vehicles at airport also likely carry 'standard' Remote IDs?
(obviously ignoring vehicles have other IDs like VINs...)

Alex

> 
>> 
>> That's about it.
>> 
>> Alex
>> 
>> Le 12/07/2023 à 16:56, Stu Card a écrit :
>>> The UAS RID rules are _not_ defined in this WG!
>>> 
>>> They are defined by Civil Aviation Authorities (CAAs) in each 
>>> jurisdiction, with coordination via the International Civil 
>>> Aviation Organization (ICAO).
>>> 
>>> Disputing the rules should be taken up with them, not with the 
>>> DRIP WG or any part of IETF.
>>> 
>>> Such rules are mentioned in DRIP docs only as background: 
>>> motivation, context & constraints.
>>> 
>>> Standard Means of Compliance with UAS RID rules, in turn, is 
>>> mostly the province of SDOs other than IETF, primarily ASTM 
>>> International. Again, disputing those standards should be taken 
>>> up with those SDOs, not us.
>>> 
>>> Only if some reference, in DRIP docs, to the rules or external 
>>> standards, is factually incorrect or unclear in expression for 
>>> understanding by DRIP protocol implementors, is it something we 
>>> should be debating here.
>>> 
>>> 
>>> Get Outlook for Android <https://aka.ms/AAb9ysg>
>>> 
>>> ------------------------------------------------------------------------
>>>
>>>
>>> 
*From:* Alexandre Petrescu <[e-mail]>
>>> *Sent:* Wednesday, July 12, 2023, 10:43 *To:* Stu Card 
>>> <[e-mail]>; Robert Moskowitz 
>>> <[e-mail]>; Carsten Bormann <[e-mail]> *Cc:* 
>>> [e-mail] <[e-mail]> *Subject:* Re: [Drip] ADSB
>>> 
>>> 
>>> 
>>> Le 12/07/2023 à 16:00, Stu Card a écrit :
>>>> Very short answers (all for which I have time):
>>>> 
>>>> The rules for RID are based not primarily on RF
>>>> considerations, but on aviation considerations.
>>> 
>>> hmmm... it's a principle that is reasonable and that could be 
>>> debated.
>>> 
>>> One will excuse me for not knowing precisely what are the RID 
>>> rules. The RID rules are defined in this WG and I will need to 
>>> look at them.
>>> 
>>> If I look at them, one day, I will look at them from this 
>>> perspective:
>>> 
>>> For example, when RID rules say 'altitude' they should say 
>>> 'altitude expressed in meters and not in feet as is currently
>>> the inherited case from WWII development of aviation'.
>>> 
>>> This kind of text could be of enormous help to implementers:
>>> they simply would need to call less functions(), because less
>>> need of conversions.
>>> 
>>> It is the same when RID rules say 'heading' or 'speed', or when 
>>> we talk about airport track orientation.  It should be made easy 
>>> to implementer to compare a heading value in a 'heading' of a
>>> UAS to that of a track. One should come up with a single common
>>> way of expressing track orientation, compatible to that of RID
>>> rules, instead of several and incompatible, as is the case in
>>> current air flight industry.  It is because if one does that 
>>> (interoperable defs of headings) then the programmer has an 
>>> easier task.
>>> 
>>> Also, about RID rules: they should say that when ASTM wants to 
>>> send position and heading they should send the NMEA statements, 
>>> without conversion.
>>> 
>>> Until then, if we can not do that, we can also have a human 
>>> listening to the radio airport and maneouvering locally or from
>>> a distance, using an innombrable number of calculators and 
>>> conversions, after having learned tomes of manuals about how to 
>>> fly things.  It is basically easier.
>>> 
>>>> 
>>>> Crewed aircraft _mostly_ fly above 500 feet, except during 
>>>> takeoff and landing.
>>> 
>>> I always had problems with this term 'crewed' aircraft.  I 
>>> noticed it also in the TVR WG, in its reverse form 'uncrewed' 
>>> aircraft.
>>> 
>>> But in reality there can be uncrewed crewed aircrafts too 
>>> (Unmanned Air Mobility device, a flying taxi, does carry a
>>> couple of persons on board - 'crew?', yet none of them actually
>>> drives the UAM - they just signed the insurance agreement).  An
>>> uncrewed aircraft is still crewed by the fact that a (group of)
>>> persons on the ground is its crew (drone Reaper is such).  There
>>> can also be these devices that are not crewed, are not
>>> continuously driven from a ground by a crew, yet there are very
>>> many eyes of people loooking at where it is going to - they're
>>> pre-programmed.  These would be the true 'uncrew' aircraft even
>>> though there are many crews simply looking at them.  They fly at
>>> more altitudes than 500 feet.
>>> 
>>> This is why I am not sure how to use this term 'crewed 
>>> aircraft'.
>>> 
>>> But I think you meant a 200 passenger aircraft like a regular 
>>> airline flight from a city to another.  Even that can be 
>>> automated (crewless?) soon.
>>> 
>>>> Small uncrewed aircraft _mostly_ fly at much lower altitudes, 
>>>> as they are flown largely not to get from one place to
>>>> another, but for photographing or otherwise sensing things on
>>>> the ground (or for recreation).
>>> 
>>> BEcause of this term 'crew' I can not say whether I agree or not 
>>> with you.
>>> 
>>> Instinctively, I'd say that there are so many other flying 
>>> aircraft that it is hard to say so easily at which altitudes are 
>>> they allowed or not, simply based on that 'crewed' qualifier.
>>> 
>>> I think the point of view of 'crewed' vs 'uncrewed' is limited in
>>> itself, leading to potentially missing some aspects.
>>> 
>>>> The FAA has established an upper limit of 400 feet AGL for 
>>>> small uncrewed aircraft flying under their rule appropriate
>>>> for most such, to provide 100 feet of vertical separation from 
>>>> these small UAS and where the crewed aircraft _mostly_ fly.
>>> 
>>> I will not oppose - maybe it is sufficient for them.
>>> 
>>> If I were to be picky, I'd say that the notion of 'AGL' itself 
>>> can be subject to debate (there are several sea levels in this 
>>> world and moreover they change as we speak) and if one asks why 
>>> then I reply that if one would like to put NMEA statements in 
>>> ASTM messages for the goal of avoiding conversions then one
>>> might be facing such aspects of precisely what is a sea level.
>>> 
>>> But I will not go to the respective SDO, so I leave it there.  I 
>>> agree they set limits where they need them.
>>> 
>>>> WRT units: yes it is a mess; no the EU does not use precisely 
>>>> the metric equivalents of feet etc. in their rules; note my 
>>>> original message said "EU rules are similar" not "EU rules are 
>>>> the same except for translation of metric units".
>>> 
>>> I agree, you did not say that.
>>> 
>>>> IETF does not get to write rules for aviation, therefore 
>>>> neither does IETF get to write rules for aviation 
>>>> communications; we can only provide technical standards for 
>>>> interoperable network protocols that _enhance_ those 
>>>> communications.
>>> 
>>> It's a good thing, because enhancing communications is always 
>>> good.
>>> 
>>> Alex
>>> 
>>>> 
>>>> -----Original Message----- From: Alexandre Petrescu 
>>>> <[e-mail]> Sent: Wednesday, July 12, 2023 
>>>> 9:45 AM To: Robert Moskowitz <[e-mail]>; 
>>>> Carsten Bormann <[e-mail]> Cc: Stu Card 
>>>> <[e-mail]>; [e-mail] Subject: Re: 
>>>> [Drip] ADSB
>>>> 
>>>> 
>>>> 
>>>> Le 12/07/2023 à 13:56, Robert Moskowitz a écrit :
>>>>> 
>>>>> 
>>>>> On 7/12/23 06:45, Carsten Bormann wrote:
>>>>>> On 2023-07-12, at 11:52, Alexandre Petrescu 
>>>>>> <[e-mail]> wrote:
>>>>>>> why not 400m
>>>>>> This is not a domain where we get to invent boundaries.
>>>>>> 
>>>>>> (Also, generally speaking, of course we should have a 
>>>>>> strong bias to using SI units, but in a domain where 
>>>>>> regulation is widely based on furlongs per fortnight,
>>>>>> we’ll have to adapt.)
>>>>> 
>>>>> And anyway it would be 125M to be a bit more than the 
>>>>> Imperial 400'.
>>>> 
>>>> True.
>>>> 
>>>> And it obviously begs the question whether in Europe they also 
>>>> have the same limit of 400' equivalent in meters.  I strongly 
>>>> doubt that an EU document would talk about a limit of
>>>> precisely 121.92 meters just because of being converted to the
>>>> easy to grasp 400 feet.
>>>> 
>>>> At that point we talk about devices that might be different in 
>>>> an EU market than in an US market.
>>>> 
>>>> What is the EU altitude limit for numerous drone aircraft to
>>>> be considered flying very low, so numerous and so low such as
>>>> to be forbidden to carry ADS-B equipment (or turn it off at
>>>> lower than that altitude if it carries one)?
>>>> 
>>>>> Why 400'?
>>>>> 
>>>>> I think it was to keep general aviation some reasonable 
>>>>> distance above people on the ground.  As the ceiling for UA 
>>>>> that is a consequence.
>>>> 
>>>> You see, I think there is an error.
>>>> 
>>>> 400 feet might be a good limit in terms of separation of
>>>> people and objects above their heads, but it is certainly not
>>>> any limit in terms of radio communication.
>>>> 
>>>> If there is to be a radio communication limit (use or not use 
>>>> ADS-B) it should be based on the power levels it uses and the 
>>>> guarantees of range. In WiFi, bluetooth and 2G..5G that's how 
>>>> they separate.
>>>> 
>>>> For example, an 5G-carrying UAS would be limited to 450meter 
>>>> altitude because that is how high the ground 5G oriented 
>>>> towards ground reaches high.
>>>> 
>>>> A bluetooth-carrying UAS (and not carrying ADS-B) would be 
>>>> limited to 100 meter altitude because that is how high a 
>>>> bluetooth device is allowed to emit, by bluetooth regulation.
>>>> 
>>>>> "They can't go any lower, you can't go any higher."
>>>> 
>>>> Strange.  Many devices, especially those who plane or glide 
>>>> like these UAS drones, and helicopters too, will stay stable
>>>> at very many low altitudes.  Their power systems - more and
>>>> more performing, allows for that.
>>>> 
>>>> I very well see a helicopter stable 100meter above the ground, 
>>>> and surely it carries an ADS-B device, if not several of them.
>>>> 
>>>>> 
>>>>> It is called boundaries to keep unequal players apart.
>>>>> 
>>>>> One of the interesting debates in this is that the 400'
>>>>> floor is to ground obstacles like radio towers.  Thus since
>>>>> big birds have to stay 400' from that 700' radio tower down
>>>>> the block, you can take your UA up to 1100' right next to
>>>>> it... Or so some claim.
>>>> 
>>>> Right!
>>>> 
>>>> RAdio towers, or radio towers with even higher anti-flash 
>>>> ('paratonnerre', fr.) on them?  That adds some 10 meter to the 
>>>> picture, to which an UAS drone would need to pay attention, 
>>>> just like helicopters need to care about power lines above 
>>>> ground too.
>>>> 
>>>>> 
>>>>> And speaking of Imperial vs Metric...
>>>>> 
>>>>> Civil aviation separation is 1000'.
>>>>> 
>>>>> This has already caused incidents where a lesser  Metric 
>>>>> distance was used by one aircraft against one using the 
>>>>> greater separation of Imperial.
>>>>> 
>>>>> Fun!
>>>>> 
>>>>> Not.
>>>> 
>>>> I agree.
>>>> 
>>>> Alex
>>>> 
>>>>> 
>>>>> Bob
>>>>> 
>>> 
>> 
> 
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> F:248-968-2824 E:[e-mail]
> 
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