SIGNAL PROCESSING FOR ARCAS FALLING SPHERE PROGRAM
Final rept. 22 May 1967-30 Nov 1968
GCA CORP BEDFORD MA GCA TECHNOLOGY DIV
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Design has been completed for a rocket probe system which will determine air density at altitudes of 70 to 130 km. The design differs from that of similar probes presently being used for obtaining density measurements primarily in the signal processing electronics. It employs a digital processor which encodes 50 complete acceleration readings per second and generates a PCM output signal whereas previous probes have been analog in nature and have made use either of a multisubcarrier FM-FM system or a commutated signal subcarrier FM-FM system. In order to confirm the validity of the electrical design, a prototype unit has been fabricated and bench tested. Temperature tests have been performed on the prototype unit and indicate that over a 0 to 60C temperature range, an accuracy figure of plus or minus 0.1 percent has been achieved for the signal processing electronics portion of the probe system. This represents an order of magnitude improvement in accuracy over a typical FM- FM system. Power for the system is supplied by an internal battery pack consisting of seven rechargeable nickel-cadmium cells which have a capacity sufficient to operate the probe system for a duration of 40 minutes at room temperature.
- Atmospheric Physics