Normally you'd use a second, free rolling spindle for that. Run the wire over the second spindle (3/4-1 loop to prevent slip) and measure the rotation of that one.
That also gotta be one hell of a drone - 1000 ft, so over 300 meters of cable, strong enough to carry the payload and itself, spindle motor that can lift all that weight, batteries - that's a lot of weight you have to lift up, even before you're adding any payload.