Navigation systems (GNSS) tend to fall right in the L-band. For example, the Russian GLONASS is in the 1.2 and 1.6 GHz range, while GPS is around 1.1, 1.2, 1.5

Navigation systems (GNSS) tend to fall right in the L-band. For example, the Russian GLONASS is in the 1.2 and 1.6 GHz range, while GPS is around 1.1, 1.2, 1.5 GHz. SMAP is in the 1.2 - 1.4 GHz range - so it overlaps with both GLONASS and GPS. So jamming in that range will affect the nav systems of the drones. This is the reason you see drones tethered with fiber optic cables - control systems might be in the same range. The "why" has more to do that the machines are made to adapt to existing systems, and those systems were designed due to the physical properties they've made to serve / solve. Both jamming and spoofing is pretty normal when you're close to Russia. And this is the reason SMAP will pick up all this jamming, because it is sensing on the same band / range.