Question regarding "positionless reports"

Just a quick question, can anything be done at the client end to cut down the number of positionless reports? To be honest i do not know why I have so many compared to the users at the top of the table?

Roughly one third of my traffic appears as positionless data. I would appreciate any help to reduce this.


Lee Armstrong

Staff member
Hi Jerry,

I think this is quite normal actually for the UK. It is just aircraft that don't transmit a position but still have Mode-S.

With our Plane Finder Radar units we use MLAT for these and turn them into position reports
Thanks Lee, that makes some sense now.

Is there something that can be done to the SBS-3 to turn it into and MLAT receiver, a GPS unit perhaps? My understanding is that the SBS does support such an addon.

Failing that are your PFR units actually for sale? I am just looking at ways to improve my feed.


Lee Armstrong

Staff member
No problem at all.

Sadly not on the other receivers. We tried our best and couldn't get the accuracy we wanted on the MLAT side of things without a GPS attached to the unit (at an extremely low level too!).

If it goes later in the stream of data you start to introduce inaccuracies which causes horrible MLAT plots! We timestamp all our data as soon as it hits the front end of the receiver and typically see accuracies to around 50 nanoseconds.

Good news though is that we do sell our receiver!
Again, thanks Lee, all good information. I just went ahead and bought a PFR unit:D

Any idea on processing, dispatch and delivery times please? I am only asking as i work alternating day and night shifts.