A new, more accurate speed and distance sensor for automotive research and development applications was introduced Tuesday at SAE 2001 by Wixom, MI-based A-DAT Corp.

Dubbed OS1, it is claimed to be the first speed and distance sensor based on digital optical correlation -- which makes it more accurate than current contact and non-contact speed sensors such as 5th wheels (contact)and radar doppler systems (non-contact), company officials say.

So-called 5th wheel systems lose accuracy when they bounce over rough pavement. Wheel speed sensors, --- another type of contact sensor --also can lose accuracy when vehicle wheels spin and slip, says Dr. Reinhold Badmann, an A-DAT spokesman.

While non-contact radar doppler is more accurate than most contact systems, Mr. Badmann says the new OS1 system is even more precise and is accurate to less than 0.1 mph from 0 to 186 mph--far better than competitive systems.

It also can be mounted almost anywhere on a vehicle and is designed to withstand harsh environmental conditions. The sensor is available now in single units. Volume production is scheduled to start in April '01.