[dmix]

This is another good read about using automated terrain mapping for cruise missile guidance systems.

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

Notably how it fit on older computer systems with limited memory by only sampling the terrain using a predefined path which a plane will travel over with imaging sensors beforehand. For minutemen style systems with predefined targets it would work well as the terrain won’t change significantly and there will be plenty of sampling data to support a high error rate and/or a relatively low resolution while moving at high speeds.

Of course it increased in quality and effectiveness over time (especially as whole topographical maps could eventually be stored, not just the path in question) but as an entirely ‘unguided’ rocket it seems to be relatively accurate for its era.

[ryanmarsh]

It knows where it is because it knows where it isn’t.

[pvg]

Isn't it an example of a highly guided missile?

[dmix]

Yes that’s correct, I meant compared to more controlled guidance by wire, radiation, satellite, etc. I phrased that improperly.

[pvg]

Fun tangent - the most unguided missile ever.

https://en.wikipedia.org/wiki/AIR-2_Genie

[chrisseaton]

> Lethal radius of the blast was estimated to be about 300 metres (980 ft). Once fired, the Genie's short flight-time [12 seconds] and large blast radius made it virtually impossible for a bomber to avoid destruction.

Why can’t you dive or climb just 150m in 12 seconds and be out of the blast range?

[duxup]

I suppose you have to be sure of the rockets detonation point to know if you are moving away in the right direction. I'm not sure that is a thing you could be sure of the moment the rocket is fired (or if you would know).

Also the target (at least initially) was large formations of Tupolev Tu-4s who can only climb 15m/s. So that puts them right on the edge, but assuming more than one rocket is fired or that they simply don't always have time to realize it was fired quickly enough... that probably does it.

[pvg]

Why 150m? It says 'radius' so if the missile is on an intercept course, 150m is not going to help you. Beside the difficulty of knowing the exact launch time and having to move a 50mx50m 180 ton bomber in fewer than 12 seconds.

[tedivm]

Fighters and interceptors can, bombers can't.

[pjc50]

300m seems like a very conservative estimate for an airburst nuke.