Can we measure picrel or must spacetime curvature be calculated in all cases?

When acceleration & gravity are taught in school it’s often said that if you suddenly woke up floating in an elevator, you’d have no way of knowing whether the elevator was far out in space or if it was in free-fall I’m in a tall building on Earth.

If you had a Warp Detector though you could just pull it out and measure the curvature of spacetime in the elevator. If it’s a simple flat grid, then you’re way the hell out there; if warped a bit, then you’re near a planet.

Can we make a warp detector like that?