Integrated CIS VLF/Omega receiver design

The design of an integrated Russian-VLF/Omega receiver implemented on a TMS320C30-microprocessor-based SPECTRUM plug-in board installed in a PC-compatible portable computer is presented. The system also requires an external antenna, pre-amp, and frequency reference. The SPECTRUM board digitizes the RF signal to 16 b and then digitally mixes with the sines and cosines of the three Russian frequencies plus 10.2, 11-1/3, and 13.6 kHz. The mixer outputs are low-pass filtered, and the comb filters are implemented for the respective epochs. The computer accesses and processes the comb filter outputs, calculating and logging signal phase and amplitude. The design allows for easy future expansion to include unique and VLF communication frequencies     

Integrated micro-electro-mechanical sensor development for inertialapplications

Electronic sensing circuitry and micro-electro-mechanical sense elements can be integrated to produce inertial instruments for applications unheard of a few years ago. This paper describes the Sandia M³EMS fabrication process, inertial instruments that have been fabricated, and the results of initial characterization tests of micro-machined accelerometers     

First spatio-temporal results from the LDEF interplanetary dust experiment

The LDEF Interplanetary Dust Experiment was unique in providing a time history of impacts of micron-sized particles on six orthogonal faces of the vehicle over a span of nearly a full year. Over 15000 hits were recorded, representing a mix of zodiacal dust, meteor stream grains, orbital debris, perhaps beta-meteoroids, and possibly interstellar matter. Although the total number was higher than predicted, the relative panel activity distribution was near expectations. Detailed deconvolution of the impact record with orbital data is underway, to examine each of these populations. Very preliminary results of the fairly crude “first look” analysis suggest that debris is the major particle component at 500 km. The data show clear evidence of some known meteor streams as sharp, tightly-focused events, unlike their visible counterparts. Some apparent debris events show similar signatures. Data from the leading and trailing edges suggest a detection of beta-meteoroids, but the analysis is not yet conclusive. Absolute fluxes and flux ratios are not yet known, since the detector status analysis is yet incomplete.