THICKNESS FEASIBILITY

DEVELOPMENT IS PROPOSED OF A SMALL, SELF-CONTAINED POWER AS THE STORAGE BATTERY TRICKLE CHARGER IN A DATA GATHERING A NEW HYBRID CONCEPT, REFERRED TO AS "LASER-ACOUSTICS." IS INTRODUCED AS A TECHNIQUE FOR DIRECTLY MEASURING ICE THICKNESS. IN THIS CONCEPT A PULSED CO2 LASER OPERATING FROM A REMOTE PLATFORM IN AIR IS FOCUSED ON ICE TO GENERATE AN ACOUSTIC FIELD HAVING RELATIVELY FLAT FREQUENCY SPECTRUM OUT TO 100KHZ. A MICROPHONE ALSO LOCATED IN AIR DETECTS THE SOUND RELECTED FROM THE ICE/WATER INTERFACE. PRECISE TIMING OF THESE SIGNALS MAKES IT POSSIBLETO ACCURATELY MEASURE THE ICE THICKNESS. INITIAL ICE FIELD MEASUREMENTS PROVED THE FEASIBILITY OF THIS CONCEPT FOR MEASURING 1 METER THICK ICE. THE EMPHASIS OF THE PROPOSED PROGRAM IS TO INVESTIGATE THE BASIC AND SYSTEM PARAMETERS THAT ARE NECESSARY TO DEVELOP THIS CONCEPT INTO AN AIRBORNE REMOTE SYSTEM FOR MEASURING ICE THICKNESS OF SEVERAL METERS TO A RESOLUTION OF 0.25-0.5 METERS. IT IS POSSIBLE THAT SUCH A SYSTEM COULD BE USED IN A STAND-ALONE MODE, OR IN CONJUNCTION WITH OTHER "ICE SENSORS" TO ACCOMPLISH THE DESIRED DEPTH RESOLUTION AND WIDE AREA COVERAGE FOR ROUTINE SURVEILLANCE OF ICE THICKNESS.