Phase coherence is ITAR? Or its use in passive radar is?

He got spanked because the use in passive radar of illumination sources such as TV transmitters is specifically identified in the USML.

USML Category XI(a)(3)(xxvii):

> (xxvii) Bi-static/multi-static radar that exploits greater than 125 kHz bandwidth and is lower than 2 GHz center frequency to passively detect or track using radio frequency (RF) transmissions (e.g., commercial radio, television stations);

There are separate ITAR provisions for radio direction finding, but these come with plenty of exclusions for systems not designed for defence applications or signals intelligence etc, and otherwise not meeting certain performance requirements, such as those in 5A001.e.

▲

tj_astro 12 hours ago | parent [-]

I was the one that originally flagged the GitHub repo as potentially being sensitive. The primary thing with passive RF use with TV or radio stations is the bandwidth issue. I've been following this particular topic for years and thus was familiar with the ITAR reg dealing with it. itar regs https://www.ecfr.gov/current/title-22/chapter-I/subchapter-M...

▲

skew-aberration 4 hours ago | parent [-]

So multistatic here is meaning multiple phase coherent receivers? MLAT is not considered multistatic passive radar?

▲

bigfatkitten 4 hours ago | parent [-]

MLAT is not radar at all for ITAR purposes.

MLAT ground stations just measure the time of arrival of the signal transmitted by the aircraft’s transponder. The difference in time of arrival at multiple ground stations allows the aircraft’s position to be calculated

▲

skew-aberration 3 hours ago | parent [-]

Very similar to passive radar. That's why I'm asking about what the legal distinction actually is. If I made my two MLAT stations phase coherent, would that make a difference?

	▲	bigfatkitten 2 hours ago \| parent [-]
		No, because it’s just a form of radio direction finding that wouldn’t be covered. Phase coherence has nothing to do with it.