<title>Magnetohydrodynamic inertial reference system</title>

Abstract

Optical platforms increasingly require attitude knowledge and optical instrument pointing at sub-microradian accuracy. No low-cost commercial system exists to provide this level of accuracy for guidance, navigation, and control (GN&C). The need for small, inexpensive inertial sensors, which may be employed in pointing control systems that are required to satisfy angular line-of-sight (LOS) stabilization jitter error budgets to levels of 1-3 microradian rms and less, has existed for at least two decades. Innovations and evolutions in small, low-noise inertial angular motion sensor technology and advances in the applications of the global positioning system (GPS) have converged to allow improvement in acquisition, tracking and pointing (ATP) solutions for a wide variety of payloads. We are developing a small, inexpensive, and high-performance inertial attitude reference system that uses our innovative magnetohydrodynamic (MHD) angular rate sensor (ARS) technology.The system's components are modular to allow ease in customizing the unit for specific applications. The basic system functions as a jitter-free fast steering mirror or reference laser assembly. For applications requiring an inertial pointing reference, the system can blend its ARS sensor information with GPS, gyroscope, and accelerometer data. This combination with the reference laser will produce a "virtual star" that is isolated from the vibrations and disturbances of the host platform and optical system and becomes an attitude, alignment, and stabilization reference for the payload. This paper describes the system's design, specifications, and projected performance for a variety of configurations and applications.

Design of a very small inertially stabilized optical space terminal

“…Optical tracking provides the primary tracking signal only up to about 4 Hz, while the angle rate sensors provide the primary feedback from about 4 Hz to the nominal stabilized platform bandwidth of 300 Hz. This class of angle rate sensors has been shown to have excellent high bandwidth, low noise jitter performance [4], and has been used in other inertially stabilized platform applications [5], [6]. In addition, the use of inertial stabilization blended with low-frequency optical tracking makes the system nearly immune to short-term optical fades [7].…”

“…The incoming beam is then only needed as a pointing reference. Inertially stabilized platforms such as the Magneto-hydrodynamic Inertial Reference Unit (MIRU), developed by Applied Technology Associates of Albuquerque, NM, have been designed for this purpose [1], [5]. For optical systems with relatively small apertures, up to approximately 75 mm, it is possible to mount the entire optical system on an inertially stabilized platform thus eliminating the need for a fast tracking system altogether.…”

The Magnetohydrodynamic Effect and Its Associated Material Designs for Biomedical Applications: A State‐of‐the‐Art Review

“…The resultant signal produces a measure of angular velocity, and can be employed easily with a static magnet without an external power source. These sensors are commonly applied when the need to correct/quantify low level vibrations [66] or high angular rates [63] .…”

“…[63][64][65] The resultant signal produces a measure of angular velocity, and can be employed easily with a static magnet without an external power source. These sensors are commonly applied when the need to correct/quantify low level vibrations [ 66 ] or high angular rates. [ 63 ] During modern metallurgic processes, such as the manufacture of high quality steels, high accuracy velocity and fl ow measurements of molten metal are necessary metrics for effective quality control.…”

Experimental Investigations of a Precision Sensor for an Automatic Weapons Stabilizer System

“…The recent literature concerning this subject [12,13,14,15,16,17,18,19,20] contain no information on the analysis of experimental investigations of precision sensors of an automated weapons stabilizer system.…”