Un-manned Autonomous Vehicle (UAV) projects depend on sensors to provide spatial information for route planning and crash avoidance. A developer of an un-manned airplane selected AR3000 distance sensors to measure the height above the ground, whether it was the landing strip, grass, trees or mountains. They needed a sensor that could measure long distances to surfaces of different reflectivities.
In their first trials, the engineers determined that the standard AR3000 could not accurately measure height above black tarmac at close ranges (<8 meters). It was later learned that not enough laser was reflecting off this dark surface and back into the collection lens. So instead, Acuity offered a new version of the AR3000 with a larger laser divergence (10 mrad instead of 2 mrad). This modified sensor device gave improved measurements at close ranges, but diminished the overall, long-range capabilities. This is how the customer arrived at a dual-sensor system. The first sensor measures from 0-50 meters and the second sensor meaasures from 10-300 meters.
To prevent cross-talk between the two laser sensors operating at the same 905 nm wavelength, the engineers used a hardware signal to trigger alternating measurements between the devices.
This same technology solution has been used by NASA AMES Research Center in Moffet Field, CA.