In Situ Data Selection And Compression As A Tool For Extending The Lifetime Of Remote Acquisiton Systems

The deployment lifetime of an in situ acquisition system is a function, primarily, of the efficient utilization of the energy source and data storage medium. Recent improvements in data and electrical energy storage will provide some improvement in deployment life and have certainly reduced the cost per bit of data storage but the greatest potential improvement is in the application of microcomputing technology to programmed data selection and compaction. Programmed or computed data selection implements, in situ, the decision making process of a data collector and results in categorization of data into high, medium, and low value groups. Data compression techniques are then used to preprocess the categories into compacted data sets with information being preserved in accordance with the designated value of the set. Computed data selection followed by efficient data compression provides, then, a powerful approach for optimizing remote data acquisition. This paper examines data categorization and compression techniques which have been applied successfully to marine and non-marine environmental measurements and discusses hardware implementation. These techniques are applied to actual time series oceanographic data and the effectiveness of each technique evaluated. Results of the evaluations, impact of each technique on system software, and a recommendation for a prototype hardware system are presented.