Magnetohydrodynamic (MHD) sensors are challenging linear accelerometers in applications requiring the measurement of angular rate and angular acceleration. The technology has demonstrated its feasibility in areas of automotive safety research instrumentation; line of-sight (LOS) stabilization for handheld and platform mounted imaging systems and sensor controlled LOS stabilization; and defense related space based pointing and tracking experiments. PRINCIPLE OF OPERATION As shown in Figure 1, an angular motion about the sensitive axis of the sensor results in a relative velocity difference between the fluid proof mass, which is highly conductive, and the normally applied static magnetic field, which moves with the sensor case. This relative velocity difference between the conductive fluid and the magnetic field generates an electric potential across the channel that is sensed directly by several versions of the MHD device.   The most sensitive MHD sensors incorporate an in situ transformer in which a simultaneous current flows through a primary winding.  In such units, the voltage across the channel is electromagnetically amplified by the integral transformer that induces a voltage across a secondary winding. The secondary winding voltage is proportional to the angular rate input to the sensor over the typical measurement bandwidth of 1-1000 Hz. MHD SENSOR accuracy is a function of increasingly larger size in either the transformer or non-transformer designs. Transformer models allow higher gain and lower noise floor for a given size of sensor.  Integral electronics control the gain and the range of the sensor. Operating characteristics of the MHD sensors in current production include: • Dynamic range > 100 dB   • High precision, better than 0.1 urad RMS in some models • Broad angular rate measurement bandwidth up to >2000 Hz • Low cross-axis angular and linear acceleration sensitivity • High g operation and survivability • No sensitivity to static g’s • High S/N ratio • Low power consumption: < 0.3 W SENSOR PERFORMANCE Although MHD sensors and gyroscopes both measure angular rate, their technologies differ in frequency response. A typical gyro can measure constant input rates (zero frequency) where the most MHD devices can measure only to around 0.1 Hz .  A typical MHD sensor has a bandwidth of 1-1000 Hz. The upper cutoff frequency (-3 dB point) of a typical gyro is usually < 100 Hz.  Figure 2 is a Bode plot of the various angular rate frequency response functions of a typical production MHD sensor model that relates the output sensitivity in V/rad/s with respect to frequency. The extremely broad frequency bandwidth capability enables the sensors to measure high frequency and transient angular motions much better than a gyro, making MHD devices more suited to applications like crash dummy instrumentation, motion and vibration analysis and angular disturbance measurements on optical or instrument platforms and antenna masts. The low frequency response of the MHD sensors can be extended to well below 0.1 Hz by use of digital filtering during post processing of the measurement data.   The upper frequency cut-off is set by electronics components internal to the sensor.  Typically set around 1000 Hz, this upper frequency cut-off can be lowered or raised to values as high as 2,500 Hz.  Where only low frequency data is of interest, the low frequency cut-off may be set at a few hundred Hz to minimize noise.  Other applications such as complex vibration analysis may have the high frequency extended to 2,000 Hz or higher.