Can you find altitude of a rocket from a photo?

[RGClark]

The image taken by SpaceShipTwo in its suborbital flight reminded me of a question I had:



The amateur team at USC also did a suborbital flight:

http://www.uscrpl.com/traveler-iv
However, the military puts limits on the accuracy of GPS of high speed craft, so the USC team couldn’t use GPS to actually prove they reached the 100 km altitude for space. After simulations, they concluded with 90% certainty their rocket reached space.

The question I had is if you had data about your camera system such as aperture and focal length could you calculate the altitude from the field of view of the image?

Robert Clark

 

[shockie]

photogrammetry

http://gsp.humboldt.edu/OLM/Courses...mate the AGL, you,of 2280m above ground level.

 

[jderimig]

Yes but accuracy is limited by the pixel resolution and how accurately you know the focal length of your lense

 

[RGClark]

Nice video by Scott Manley about how you can see the curve of the Earth at high altitude:



(This is a 360/VR video so moving the device you’re viewing it on allows you to see different angles.)

He discusses two methods that might allow you to calculate altitude. First he notes the difference in the curvature visible as you go higher. But another way I hadn’t thought of: as you go higher the apparent angle between the vertical and the horizon grows larger, and in fact beyond 90 degrees. And it gets larger as you go higher.

This might be the easiest way to determine altitude.

Robert Clark