[Uncle Chip]

The later stream focused on frequency changes involving the "Doppler effect," he said, revealing the plane's speed.

Very Interesting. So they had Speed and Time and Distance.

[Norseman]

>>Very Interesting. So they had Speed and Time and Distance.<<

I suspect you’ll see him correct his assertion that they had the plane’s speed.

Actually, what they would have been able to derive is the plane’s speed relative to the satellite, but not the absolute speed.

For example they would be able to determine how fast the plane was either approaching the satellite or flying away from it. But unless it was flying directly away or toward it (on a radius with the satellite at the center) they would not get the true speed of the plane.

For example, if the plane was flying a circumference (perpendicular to the radius) at the ping time, it would look like it was stationary in the air from their calculation because the Doppler Effect would be zero.

If you think about that, it would be more accurate to say that it provides clues to the “direction” of the plane’s flight at the ping time, rather than the speed of the plane at that time. Even then, though, there would be two options, but those could possibly be sorted out at the next ping when a new location arc would be generated.

Also, their calculation must assume the actual speed of the plane, or at least and upper and lower range.