Nick A. Demma

Coherent CO 2 laser communication system with modulable retroreflectors

A coherent CO(2) laser communication system that yields high-quality voice communications between a transmit-receive station and a remote site (24 km) where modulable retroreflectors are located was developed. The potential range capability of this system was 80 km, and the system was improved by 20 dB in the signal-to-noise ratio over a direct-detection system.

Magnetic lateral guidance sensors for automated highways

Automated highway systems will need sensors both for longitudinal guidance (intelligent speed control) and for lateral guidance relative to the center of the traffic lane. A magnetic sensor combined with a practical magnetic highway marking system provides an all-weather, cost effective lateral guidance technique. A practical system must have robust performance under all weather operation, and be producible at a reasonable cost. Previous schemes have suffered from weather related performance problems, cost of the sensor portion on the vehicle, or the cost of the highway infrastructure. The subject system uses a high sensitivity magneto-resistive sensor and a magnetic marking tape which is a variant of existing traffic marking tapes. In addition to providing lateral position information, the system can encode ancillary data that can be received by the vehicle sensor. An important data item is the road curvature for the next segment of road. If the system operates with closed loop autonomous lateral control, such feedforward data is important for good performance at highway speeds. A preliminary feasibility demonstration illustrated that the system provides a high signal to noise ratio, and good accuracy.