# MLAT error, or what is wrong?

**URL:** <https://discussions.flightaware.com/t/mlat-error-or-what-is-wrong/67031>\
**Category:** ADS-B Flight Tracking\
**Created:** [July 12, 2020, 8:32am UTC](https://discussions.flightaware.com/t/mlat-error-or-what-is-wrong/67031 "2020-07-12T08:32:38Z")\
**Posts on this page:** 7\
**Page:** 1

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**Author:** ![carstenks](https://sea1.discourse-cdn.com/flex019/user_avatar/discussions.flightaware.com/carstenks/32/116236_2.png) [@carstenks](https://discussions.flightaware.com/u/carstenks)\
**Post date:** [July 12, 2020, 8:32am UTC](https://discussions.flightaware.com/t/mlat-error-or-what-is-wrong/67031/1 "2020-07-12T08:32:39Z")

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Have a look at this screenshot - The “plane” has been on my radar for over 30 minuttes, is it MLAT calculations going wrong? It’s way past my range.

VRS shows it to be 110 nm away, where PiAware and TAR1090 shows the 450 nm. Malformatted messages, testsignal or what happen.

 ![2020-07-12 10_27_42-Greenshot](https://us1.discourse-cdn.com/flex019/uploads/flightaware/original/3X/4/1/411a8ffc87dc7fa947e3cbe528be29d243d09a61.jpeg)

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**Author:** ![obj](https://sea1.discourse-cdn.com/flex019/user_avatar/discussions.flightaware.com/obj/32/118984_2.png) [@obj](https://discussions.flightaware.com/u/obj)\
**Post date:** [July 12, 2020, 8:41am UTC](https://discussions.flightaware.com/t/mlat-error-or-what-is-wrong/67031/2 "2020-07-12T08:41:06Z")

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I doubt there is much analysis possible here unless you captured the raw position messages at the time. It might be a CPR decode error where it picked the wrong cell. What mlat data source are you using?

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**Author:** ![carstenks](https://sea1.discourse-cdn.com/flex019/user_avatar/discussions.flightaware.com/carstenks/32/116236_2.png) [@carstenks](https://discussions.flightaware.com/u/carstenks)\
**Post date:** [July 12, 2020, 8:42am UTC](https://discussions.flightaware.com/t/mlat-error-or-what-is-wrong/67031/3 "2020-07-12T08:42:50Z")

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Thanks… It’s still on my radar. Any way to get the raw data at ease? Won’t spend days figuring it out 🙂

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**Author:** ![obj](https://sea1.discourse-cdn.com/flex019/user_avatar/discussions.flightaware.com/obj/32/118984_2.png) [@obj](https://discussions.flightaware.com/u/obj)\
**Post date:** [July 12, 2020, 8:44am UTC](https://discussions.flightaware.com/t/mlat-error-or-what-is-wrong/67031/4 "2020-07-12T08:44:21Z")

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`view1090-fa --no-interactive --show-only (ICAO address in hex) 2>&1 | tee capture.txt`

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**Author:** ![wiedehopf](https://sea1.discourse-cdn.com/flex019/user_avatar/discussions.flightaware.com/wiedehopf/32/114045_2.png) [@wiedehopf](https://discussions.flightaware.com/u/wiedehopf)\
**Post date:** [July 12, 2020, 8:45am UTC](https://discussions.flightaware.com/t/mlat-error-or-what-is-wrong/67031/5 "2020-07-12T08:45:32Z")

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I’d say the ICAO is being used by more than one aircraft?  
(looks to me like the international VFR squawk 7000 was also entered as ICAO hex id  
[Aviation transponder interrogation modes - Wikipedia](https://en.wikipedia.org/wiki/Aviation_transponder_interrogation_modes#ICAO_24-bit_address))

And/or it’s intermittently sending bad ADS-B positions and then being located by MLAT again?  
Could be lots of stuff … hard to analyze.

Yeah after looking at it a bit … think it’s just two aircraft using the same hex.

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<div class="post-metadata">

**Author:** ![carstenks](https://sea1.discourse-cdn.com/flex019/user_avatar/discussions.flightaware.com/carstenks/32/116236_2.png) [@carstenks](https://discussions.flightaware.com/u/carstenks)\
**Post date:** [July 12, 2020, 10:19am UTC](https://discussions.flightaware.com/t/mlat-error-or-what-is-wrong/67031/6 "2020-07-12T10:19:24Z")

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With my luck, the “plane” was gone when i saw how to capture raw data…

If it happens again, i’ll try to capture some data…

Thanks for replies. 🙂

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**Author:** ![system](https://sea1.discourse-cdn.com/flex019/user_avatar/discussions.flightaware.com/system/32/38558_2.png) [@system](https://discussions.flightaware.com/u/system)\
**Post date:** [July 12, 2021, 10:19am UTC](https://discussions.flightaware.com/t/mlat-error-or-what-is-wrong/67031/7 "2021-07-12T10:19:28Z")

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