REAL-TIME SPECTRAL-ANALYSIS ALGORITHM FOR SPACE PLASMA 3-DIMENSIONAL ION MASS SPECTROMETERS

We have developed a fast real-time spectral analysis algorithm for spa ce plasma three-dimensional (3D) ion mass spectrometers that deconvolv es contributions to time-of-flight ion mass spectra for various ion sp ecies abundances. The algorithm is composed of a set of coupled linear equations with constant coefficients. The algorithm is implemented so that in-flight computers need only apply a predetermined number of mu ltiplies and adds to the spectral data. The algorithm allows run times to be short and highly predictable, can accommodate the presence of b ackground in the ion mass spectra, and can be updated to adjust to cal ibration changes and unexpected instrument anomalies or failures. Spac e plasma 3D ion mass spectrometers have the capability of generating l arge volumes of data and if not compressed would produce data rates th at far exceed the telemetry rate usually allocated to space plasma ins truments. The real-time application of this algorithm allows one to ac hieve compression ratios greater than 100 for the spectral data withou t introducing systematic errors to the computed ion abundances. It als o allows the application of other higher level data compression techni ques to provide additional compression of the telemetry data. Finally, the algorithm can be thought of as a way to increase the mass resolut ion of the ion spectrometer.