UK - MODE S and battling level busts
Joined: May 2002
Posts: 351
Likes: 0
From: UK
How many DAPS are available then? I know that some of the current DAPS seem to be pretty useless to the controller as they are (roll angle...), if it's a case of just replacing good with bad it will be good to know how many new ones we canhave on top of what is already available.
Joined: Oct 2004
Posts: 273
Likes: 0
From: South of UK
Minesapint,
The current 8 or so DAPs mandated across Europe as Enhanced Surveillance capability are supplied via 3 BDS registers held on the transponder. Each of these registers requires an interrogation to be made to obtain the content.
BDS 4,0 Selected Vertical Intent - Selected Altitude, Baro Pressure setting
BDS 5,0 Track and Turn Report - Roll Angel, True Track Angle, Ground Speed, Track Angle Rate, True Airspeed
BDS 6,0 Heading & Speed Report - Magnetic Heading, IAS, Mach No, Baro Alt Rate, Intertial Vertical Velocity.
Any other DAPs would have to be obtained by downloading further BDS registers, of which many are as yet undefined or not yet stable in agreed content. The problem is that the Mode S interrogator being deployed can only perform fixed period extract of up to 4 BDS registers (outside of those needed for Elementary Surveillance). 3 have been taken up already as above, so only one more register can be downlinked from the interrogator. It may be that to obtain other DAPs from other registers, someone actually builds a Ground Datalink Processor (GDLP) to connect to interrogator as Mode S was intended, or overlapping interrogators will have to interrogate for different DAPs to get them all down to the SDP system that presents the data or uses them in controller tools.
Alternatively, if one of the registers has content that is not much use, then it could be ditched in preference to another one but the airlines would be pretty annoyed if they kitted out for it and the info is not used.
Either way, it's not as straightforward as looking at new DAPs and saying "we want those"
RS
The current 8 or so DAPs mandated across Europe as Enhanced Surveillance capability are supplied via 3 BDS registers held on the transponder. Each of these registers requires an interrogation to be made to obtain the content.
BDS 4,0 Selected Vertical Intent - Selected Altitude, Baro Pressure setting
BDS 5,0 Track and Turn Report - Roll Angel, True Track Angle, Ground Speed, Track Angle Rate, True Airspeed
BDS 6,0 Heading & Speed Report - Magnetic Heading, IAS, Mach No, Baro Alt Rate, Intertial Vertical Velocity.
Any other DAPs would have to be obtained by downloading further BDS registers, of which many are as yet undefined or not yet stable in agreed content. The problem is that the Mode S interrogator being deployed can only perform fixed period extract of up to 4 BDS registers (outside of those needed for Elementary Surveillance). 3 have been taken up already as above, so only one more register can be downlinked from the interrogator. It may be that to obtain other DAPs from other registers, someone actually builds a Ground Datalink Processor (GDLP) to connect to interrogator as Mode S was intended, or overlapping interrogators will have to interrogate for different DAPs to get them all down to the SDP system that presents the data or uses them in controller tools.
Alternatively, if one of the registers has content that is not much use, then it could be ditched in preference to another one but the airlines would be pretty annoyed if they kitted out for it and the info is not used.
Either way, it's not as straightforward as looking at new DAPs and saying "we want those"
RS
