Measuring the angle to an object with IR sensors

I would like to be able to use IR emitter/receivers to measure the ANGLE to an object. As far as I am aware this is how the Sharp IR distance sensors work, by using triangulation to measure the angle of a reflected IR light source to work out the distance to the object.

I just need to work out the angle an object is from the emitter/receiver pair and by using more than one pair I could then work out (using triangulation) the distance to the object as well its position in 2D space.

However, researching this has proved fruitless so far. I believe the receiving end of a Sharp distance sensor is a pin photodiode (correct me if I am wrong?). If it is not a pin photodiode then what is it? What measures the angle of the IR beam?

If anyone could help with this it would be appreciated.

Thanks,

Mike

I believe the Sharp sensor uses a linear array and the reflected spot moves along this as the distance changes due to the shape of the receiver optics (like a camera lens).

If the Sharp distance sensor has sufficient range, you can use 3 (or more) to give intersecting circles which can be used to calculate xy coordinates.

This patent covers some of the Sharp technology: