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Dump1090 problems with adsbscope

Started by K9ACT, June 20, 2015, 02:07:33 AM

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K9ACT

Quote from: IanH on June 23, 2015, 06:23:52 PM

I ran that FR24 batch file with adsbScope set up as shown below and it worked!

Me too.  Works fine with ADSBscope and with the older version of FR24feed.

Now for plan C.

It needs to work with the current (new) version of FR24feed. Unfortunately, I do not know how to determine the versions of these (dos?) sort of programs.

The new version of FR24feed provides a whole page of stats and charts on one's feed in addition to feeding the mlat system.  It also makes it possible to use the radar version of FR24.

The older version simply feeds the adsb into the system and might as well be into a sewer as far as the feeder is concerned.

So, if you or anyone has any ideas here, we are getting close but no cigar yet.

.....................

Don't know if this is a good place to ask but I am pretty confused on what Mlat really is.

All I have read is that it is a way to track planes that are not transmitting adsb but have yet to hear what they are transmitting that provides the data displayed.

In my limited experience, the Mlat planes are as likely as the FAA planes to not really be where the are supposed to be.  Every adsb plane on my display within line of sight can be seen but this is far from the case with either of the others.  So how does it really work?

js

Astronomy, Beer, Cheese, Fiber, Gems,
Nature, Radio, Sheep, Sausage, Silver

      http://schmidling.com


Anmer

Quote from: K9ACT on June 24, 2015, 01:40:09 AM
Don't know if this is a good place to ask but I am pretty confused on what Mlat really is.

It's best to keep to the original message topic but there's a free Guide here that explains MLAT on page 15:

http://radarspotting.com/forum/index.php?action=tpmod;dl=item92
Here to Help.

K9ACT

Quote from: Anmer on June 24, 2015, 08:18:07 AM
Quote from: K9ACT on June 24, 2015, 01:40:09 AM
Don't know if this is a good place to ask but I am pretty confused on what Mlat really is.

It's best to keep to the original message topic but there's a free Guide here that explains MLAT on page 15:

http://radarspotting.com/forum/index.php?action=tpmod;dl=item92


Not sure I see the answer to my question there.

I understand the geometry involved but if the planes do not have Mode S capability, how are the Mode S receivers  getting data from the plane to make the calculations?

Jack




Anmer

Quote from: K9ACT on June 24, 2015, 04:15:14 PM
I understand the geometry involved but if the planes do not have Mode S capability, how are the Mode S receivers  getting data from the plane to make the calculations?

MLAT plots can be calculated for Aircraft transmitting non-positional messages on 1090 MHz Mode-S.

Page 15:

As mentioned earlier, not all Mode-S transmissions include positional data. Typically
private and military aircraft don't transmit positions nor do some larger aircraft
operated by airlines such as Flybe.

Mlat uses data from three or more Mode-S receivers to calculate the aircraft's
location by means of geometry. The PP Mlat tutorial explains:

If you know the precise distance between an unknown location and three
known locations, then it is simply a matter of geometry to determine the
position of the unknown. In the case of multilateration using radio signals,
the distance is measured in terms of the travel time of the signal, at the
speed of light (300 metres per microsecond).


As I said, it's a complex subject. Let's just say that PP Mlat is sometimes able to plot
the whereabouts of non-positional Mode-S aircraft. Commercial grade Mode-S
receivers, such as Kinetic's SBS-2 offer Mlat but at a much higher price than the
enthusiast can justify


If the aircraft isn't transmitting any Mode-S messages, MLAT (as we know it) can't be used to plot its position.
Here to Help.

Triple7

Quote from: Anmer on June 24, 2015, 04:37:57 PM
If the aircraft isn't transmitting any Mode-S messages, MLAT (as we know it) can't be used to plot its position.

Which is where the Beamfinder Plus feature comes into play.

From the PP help file:

"Mode-A/C transponder pings are transmitted in response to interrogation pulses from ground-based or airborne radar systems. Mode-A interrogations return the regular squawk code and Mode-C interrogations return the encoded altitude. Mode-A/C radar sites have a characteristic rotation period and a characteristic pulse repetition interval. If you are lucky, for some sites those values will be unique within your reception range."

Sorry to perpetuate the thread drift.

Tim
SBS-1eR, FA ProStick + 1090 filter

Anmer

Quote from: Triple7 on June 24, 2015, 05:49:13 PM
Sorry to perpetuate the thread drift.

I was hoping this wouldn't happen. :-[

Back on topic please.
Here to Help.

K9ACT

Quote from: Anmer on June 24, 2015, 04:37:57 PM

As I said, it's a complex subject. Let's just say that PP Mlat is sometimes able to plot
the whereabouts of non-positional Mode-S aircraft. Commercial grade Mode-S
receivers, such as Kinetic's SBS-2 offer Mlat but at a much higher price than the
enthusiast can justify[/color]

If the aircraft isn't transmitting any Mode-S messages, MLAT (as we know it) can't be used to plot its position.

I guess I missed the distinction of the "non-positional Mode-S".

So the question is, what is this info and do I assume that my receiver is picking this up and forwarding it to FR24?

js

Anmer

Except for those using a Radarcape or the FR24 free receiver, the feeder utility will only be sending positional messages - ADS-B:

http://www.flightradar24.com/how-it-works

If you have other questions not related to "Dump 1090 problems with adsbscope", please post in another message thread.
Here to Help.