Howard B. French

Development of a MEMS gyroscope for northfinding applications

We report progress toward a MEMS gyroscope suitable for northfinding in pointing and targeting applications. In-run bias stability of 0.03 deg/hr and ARW of 0.002 deg/rt(hr) have been achieved. Gyro performance was measured on tuning-fork type MEMS gyroscopes using DSP-based breadboard electronics. These bias stability and ARW results are within about 6X and 2X, respectively, of meeting the typical gyrocompass requirements for pointing and targeting applications (1 milliradian azimuth precision at 65 degrees latitude with 5 minute integration time). A MEMS gyrocompass meeting these requirements would substantially reduce the size, weight and power of pointing and targeting instruments. The test methodology will be presented, as well as test data on carouseling the sensor to reduce the effects of long-term bias drift.

An optical polarization survey for BL Lacertae objects and highly polarized quasars

We present the results of an extensive optical survey for highly polarized objects. The survey is complete to a B magnitude of 20 and covers 560 square degrees. We did not find any confirmed BL Lac objects, highly polarized quasars, or blazars, but we are able to constrain the surface density of the various populations of linearly polarized objects. Our constraints on the numbers of a population of polarized objects are a function of the duty cycle and the degree of polarization of the objects being constrained. We rule out the presence of an abundant population of radio-quiet BL Lacertae objects

A multi-sensor approach to airport surface traffic tracking

A dual sensor system using a large number of inexpensive short range sensors can act as a valuable adjunct to surface surveillance radars, as well as provide a low cost tracking system for non-radar equipped airports. A measurement program was conducted to collect data on magnetic and infrared signatures of aircraft and other vehicles on airport surfaces. The data indicates that short range sensors can provide detection and tracking of vehicles, and may be able to perform some classification function.<<ETX>>

Solid state magnetic azimuth sensor for small satellites

The Earths magnetic field can provide attitude reference for satellites. Because of the nature of the terrestrial magnetic field, magnetic sensing is primarily used to sense azimuth, with a horizon sensor providing reference in the other two axes. The magnetometer azimuth sensor is small, light, and inexpensive. A new solid-state magnetometer based on magnetoresistive techniques can provide azimuth determination with an accuracy equal to existing techniques. It has even more favorable advantages, however, in size, weight, power consumption, and cost compared to conventional techniques. A magnetic azimuth sensing system based on this magnetometer should provide azimuth information to about 0.5 degrees, a limit imposed by uncertainties in the Earths field rather than limitation in sensitivity of the solid-state sensor.