Hacking an IR distance sensor: would work??

Hello,
say I want to find precisely the distance between a sensor and a moving point that is not necessarily right in front of the sensor. Is having the emetting LED of an IR sensor on the moving point and having only the receiver left in the sensor would work? Does the range just double or there would be complications?
Thank you!

It would only increase range and not add on rangefinding capability to a proximity sensor. But it's probably a Sharp IR sensor which uses triangulation so doing so having a IR source on the target would increase range but remove the rangefinding capability.

That's what I was afraid of. Thanks!