Presidential limo tracking

[AM909]

No failure. It's likely VENUS 62's position was derived via ADS-B and 28000's via MLAT. You'll see this alot with military aircraft.

http://www.multilateration.com/downloads/MLAT-ADS-B-Reference-Guide.pdf

We need a wiki page on this subject.

Correct – 28000 was MLAT and the VENUS62 was ADS-B. I guess, then, that either there is not sufficient coverage of receivers near KADW for MLAT to work effectively (kind of surprising, given the number of high-interest activities there), or there was a temporary feed problem in this case. Anyone monitor regularly there? Is it a routine problem that may need investigation/remediation?

28000:

VENUS62:

 

[slayer816]

Anyone monitor regularly there? Is it a routine problem that may need investigation/remediation?

Every day. I also feed.

MLAT requires calculation with other feeders to get a more reliable location. If an MLAT aircraft has tracking issues; it's either a lack of multiple feeds communicating with the aircraft (and/or the server), or there simply is not enough receivers in the area at all. It's not a "problem" per se, it is a limitation based on how it works.

Obviously the only solution is to have more feeders to track the aircraft. MLAT isn't going anywhere soon The fact that it is NOT a precise tracking system is actually a positive thing to certain individuals; mainly the military and executive transportation groups.

 

[AM909]

@slayer816: So is it a routine issue at KADW with MLAT? Whether it presents a security problem or not is an important, but different issue. If it's supposed to work, though, I just want to know if we need to ask/tell ADSBX about it. If they have (say) 6 receivers in range of final and they're not working correctly due to perhaps interference from nearby high-power sources (that could be filtered), etc. There's obviously at least one reciever feeding clean ADSB data.

 

[slayer816]

@slayer816: So is it a routine issue at KADW with MLAT? Whether it presents a security problem or not is an important, but different issue. If it's supposed to work, though, I just want to know if we need to ask/tell ADSBX about it. If they have (say) 6 receivers in range of final and they're not working correctly due to perhaps interference from nearby high-power sources (that could be filtered), etc. There's obviously at least one reciever feeding clean ADSB data.

I apologize if I was unclear.

The fact that you see the aircraft at all means it's working. It "works better" by having more receivers tracking a target and those receivers having a strong link with each other. That's in a sense how MLAT works. It's older technology and it will never be as good as say...ADS-B for example. It was only meant to get an approximate position by measuring the different signals and comparing that with other receivers. Basically, there's nothing to "fix" or "report." There's a limit to the technology and the only way to improve MLAT is to A) improve the number of receivers tracking a target and B) improve the strength of the receivers to each other and the server.

 

[radiomankc]

Easy solution… If you get within 1,000 feet of the motorcade, every RF device you have with you dies until they are roughly more than 1,000 feet. I just use that as an example as they adjust the jammers output power depending on their location to various scenarios. The jammers usually cover from about 25MHz to just over 3GHz. The jammers protect a host of differ scenarios…. Top of the list is a RF detonated explosive. Do some research. Quite interesting. What you might read about is nowhere near the sophistication of what USSS uses.

 

[AM909]

It turns out there's an almost complete lack of feeders between DC and Chesapeake Bay south of Annapolis: ADSBexchange.com Feeder Coverage . I asked whether this was intentional and the terse response from ADSBx was essentially "so host one".

 

[slayer816]

It turns out there's an almost complete lack of feeders between DC and Chesapeake Bay south of Annapolis: ADSBexchange.com Feeder Coverage . I asked whether this was intentional and the terse response from ADSBx was essentially "so host one".

That will happen. Raspberry Pi's are cheap and do a lot of neat things. SDR's are cheap also. My setup cost me around 50 bucks (I have a fancy one with WiFi and switched power, some are cheaper).