Currently they see Mode A+C and some units, perhaps most, see Mode S.
If they are to see ADS-B emissions they will need to decide whether to see only SIL=3, or the whole lot. And if they see SIL=0, will they be able to prosecute using that data?
Obviously it must be very tempting to use the data for detecting busts, because a single receiver (with a simple vertical rod antenna) on top of a hill can pick up stuff from the whole southern UK. Apply that to a 3D CAS map and you get instant reports. Then if you want or need to, you can go back to other radar data to back it up for a prosecution; no lawyer will be able to dispute radar data, even if the original tip came from the ADS-B pickup.
According to an article I have just read in FTN the UK had 1358 busts in 2018.
SIL is only one parameter that needs to be correct for ATC to integrate ADS-B data for surveillance purposes and end up on a controllers scope. The current EU mandate only applies to aircraft above 5700 KG and 250 Kt TAS cruise capability. With a few exceptions, ADS-B is being used for turbojet and high altitude. I am sure it will be used at major high density airports. US has an airspace mandate A, B, C, mode C veil, above 10000 in E. Australia has an IFR mandate. Others are still in the works and most are not currently mandated at low altitudes, if at all.
This is from European Aviation Safety Agency, Certification Specifications and Acceptable Means of Compliance for Airborne Communications, Navigation and Surveillance CS-ACNS
CS ACNS.D.ADSB.100 Integrity
(a) The ADS-B Out system integrity is designed commensurate with a ‘major’ failure
condition for the transmission of the following parameters:
(1) ICAO 24-bit aircraft address;
(2) Airborne Horizontal Position — Latitude and Longitude;
(3) Airborne Navigation Integrity Category: NIC;
(4) Airborne/Surface Navigation Accuracy Category for Position: NACp;
(5) Airborne/Surface Source Integrity Level: SIL;
(6) Airborne/Surface System Design Assurance: SDA;
(7) 1090 ES Version Number;
(8) Airborne velocity over Ground — East/West and North/South;
(9) Airborne/Surface Navigation Accuracy Category for Velocity: NACv;
(10) Emitter Category;
(11) Surface Horizontal Position — Latitude and Longitude;
(12) Surface Navigation Integrity Category: NIC;
(13) Surface Ground Track;
(14) Movement (surface ground speed);
(15) Length/width of Aircraft;
(16) GPS Antenna Offset;
(17) Geometric Altitude;
(18) Geometric Altitude Quality: GVA;
Do you think SIL=3 will be a requirement for ATC to monitor ADS-B at all?
In Europe there will be almost no GA traffic on that, so if one wanted to do large scale surveillance it would not be very productive.
Peter wrote:
Currently they see Mode A+C and some units, perhaps most, see Mode S.If they are to see ADS-B emissions…
I know that Swedish ATC can see ADS-B. I would be very surprised if ATC in other countries can’t.
Peter wrote:
Do you think SIL=3 will be a requirement for ATC to monitor ADS-B at all?
SIL = 3 is required in the US for the ADS-B Out to be used by ATC for Surveillance.
That would make sense but I wonder if Europe will do something different, given the various promotions of the SIL=0 products. I was reading some stuff today and it looks like even the UK CAA is getting into this. Sky Echo 2 is SIL=1 and is being pushed pretty hard. But I still can’t see ATC spending millions on picking up these emitters.
A couple of years ago, after I upgraded my transponder to ES, I asked Scot Info whether they could see if it was working. They couldn’t at that time, but handed me over to Belfast who kindly comfirmed that the Maule was squittering extensively.
So UK ATC use of ADSB was patchy in 2016/7, but perhaps less so now.
Peter wrote:
But I still can’t see ATC spending millions on picking up these emitters.
Well they are spending the money picking up the emitters anyway. The SIL level is a software setting.
after I upgraded my transponder to ES
That would be a data point for UK ATC seeing SIL=3.
However, is 1090ES same as ADS-B OUT?
Well they are spending the money picking up the emitters anyway. The SIL level is a software setting.
Would you be able to elaborate on how the system will operate?
They can’t use SIL=0/1 for separation because the altitude is not baro; it is from a “cheap” GPS, probably not even geoid corrected (that’s worth ~150ft in the UK and most of Europe).
Peter wrote:
They can’t use SIL=0/1 for separation because the altitude is not baro; it is from a “cheap” GPS, probably not even geoid corrected (that’s worth ~150ft in the UK and most of Europe).
Geometric altitude can’t be compared with pressure altitude without correction of Geometric altitude for the Geoid, then modeled to determine a temperature correction to an equivalent MSL altitude and then corrected from MSL to a pressure altitude. Without all these corrections, the error can easily be +/- 1000 feet, and in some cases, more.
