Ardupilot (and a number of other open source flight stacks) do 'real' guidance. GNSS based, or optical flow, or whatever other source you want. You can program drones (multirotor, fixed wing, vtol, whatever) to go to exact coordinates, following whatever flight paths you want. This is something a teenager can put together in a weekend with parts ordered from banggood or gearbest or any other number of chinese webstores.
For a 1000km range, sure, maybe they didn't do it themselves, but nothing stopping them from just ordering slightly larger off-the-shelf drones from China. But lots of small drones is cheap and easy, and harder to stop.
That's a really cool and super inexpensive long range drone! Thanks.
The Houthi models are jet powered, cruise at 450mph, and can fly for 2 hrs on 500 lbs of jet fuel, which requires a 10 cubic foot volume fuel tank. The interior of the fuselage has around 70 cubic feet of capacity, which is more than enough for the fuel (even enough for a 900 mile each way round trip if desired), the controls, and the payload. They have a solid fuel rocket booster on the back as they are sled launched. Once up to flight speed the jet takes over and the rocket element drops off. They are really cool drones and within the scope of what the serious amateur community in the US and elsewhere is experimenting with. Some guys even are building their own jet engines from scratch.
The guidance systems are a done deal. Can DIY or can buy off the shelf. My kids build drones and program the guidance systems on them themselves (one started at age 8). It's fun and there's even online classes telling you everything you need to know. Ours currently use inertial guidance and GPS and have no problem getting somewhere with great accuracy. We've also got a celestial navigation system under development which works even when there is no GPS.
Houthis mentioned they have local assist at the end of the flight which makes sense to deal with GPS jamming. The region they hit contains significant Shia populations who hate Saudi Arabia and have even revolted against the Kingdom in the past. Once you're at the last mile if for any reason there's a question about the target, local observers can and do provide guidance assist.
People saying Houthis are too dumb or primitive to make drones are warmongering anti-Iranians, IMHO. Houthis have systematically and incrementally been developing this technology for years now to defend their homeland and have shown off their drones. There's no question the Houthi drones have the capabilities we are seeing.
For a 1000km range, sure, maybe they didn't do it themselves, but nothing stopping them from just ordering slightly larger off-the-shelf drones from China. But lots of small drones is cheap and easy, and harder to stop.
Source: I work in the commercial drone industry.
Edit: here's an off-the-shelf drone with 1000km range, costs $4.5k: https://www.muginuav.com/product/mugin-4450mm-uav-ht-tail-pl...