The whole process is one where you convert this or that either to the speed of light and flight time or to phase error on fringes. To do the phase error stuff you already need to know where you are within one wavelength or it's ambiguous by that amount.
Simple answer - no free lunch. The tighter you want the accuracy to be, the more complex it gets.
There is a TI chip that will get you sub nanometer information for cheap. It needs a conductive target to work against..... (like say a big piece of cast aluminum tooling plate)
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Back to figuring out where I've mucked up figuring out the head motion ....
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Let's say you have a magic gizmo that will give you X, Y and Z data to nanometer resolution in 10 seconds. You decide to do a survey of the volume at the 1 mm level (which may not be fine enough). You survey a normal LISA over the 200mm diameter and 250 mm height. Each layer has ~31,416 points. The survey has about 8 million points in it. It will take you about 3 years to complete the survey. A 2X larger LISA has 8X the points, so you can the same survey in a bit more time, or a lower resolution (2mm) survey in the same time. Stick with the large volume and go to a 32 mm resolution and you are back into the ~8 hour range.
Simple answer - no free lunch. The tighter you want the accuracy to be, the more complex it gets.
There is a TI chip that will get you sub nanometer information for cheap. It needs a conductive target to work against..... (like say a big piece of cast aluminum tooling plate)
--------------
Back to figuring out where I've mucked up figuring out the head motion ....
------------
Let's say you have a magic gizmo that will give you X, Y and Z data to nanometer resolution in 10 seconds. You decide to do a survey of the volume at the 1 mm level (which may not be fine enough). You survey a normal LISA over the 200mm diameter and 250 mm height. Each layer has ~31,416 points. The survey has about 8 million points in it. It will take you about 3 years to complete the survey. A 2X larger LISA has 8X the points, so you can the same survey in a bit more time, or a lower resolution (2mm) survey in the same time. Stick with the large volume and go to a 32 mm resolution and you are back into the ~8 hour range.