Ah. That's where my flawed memory came from

"... Iranian engineer's assertion that the drone was captured by jamming both satellite and land-originated control signals to the UAV, followed up by a GPS spoofing attack that fed the UAV false GPS data to make it land in Iran ..."

Wikipedia has more of the story https://en.wikipedia.org/wiki/Iran%E2%80%93U.S._RQ-170_incid...

That was disputed "... GPS is not the primary navigation sensor for the RQ-170..."

Anyway, thanks!

Can you jam the only non-encrypted part of GPS?

Kind of. The GPS signal portfolio is evolving. In the beginning, the encrypted code was broadcast on two frequencies, L1 and L2. The public code was only on L1. So you could in theory jam just L1 to block the un-encrypted portion, but why would you?

In recent years GPS modernization means satellites have been using new codes on L2 (L2C) which are un-encrypted. Only about 18 of the satellites carry that capability at this time.

How else are you going to land the drone safely? I think the idea is jam the encrypted data, spoof the unencrypted part to point to your location.

As far as I know military devices always use the anti-spoof (encrypted) military code, and never the commercial code.

Given the public knowledge of the old P(Y) code and the new M code, you can remove 'probably' from your first sentence.

https://en.wikipedia.org/wiki/GPS_signals

I agree. At the time people were noting the drone the Iranians were showing off was the wrong color, which would imply they fixed some damage and repainted it.