Modern molecular electronic transfer (MET) angular motion sensors combine high technical characteristics with low cost. Self-noise is one of the key characteristics which determine applications for MET sensors. However, until the present there has not been a model describing the sensor noise in the complete operating frequency range. The present work reports the results of an experimental study of the self-noise level of such sensors in the frequency range of 0.01–200 Hz. Based on the experimental data, a theoretical model is developed. According to the model, self-noise is conditioned by thermal hydrodynamic fluctuations of the operating fluid flow in the frequency range of 0.01–2 Hz. At the frequency range of 2–100 Hz, the noise power spectral density has a specific inversely proportional dependence of the power spectral density on the frequency that could be attributed to convective processes. In the high frequency range of 100–200 Hz, the noise is conditioned by the voltage noise of the electronics module input stage operational amplifiers and is heavily reliant to the sensor electrical impedance. The presented results allow a deeper understanding of the molecular electronic sensor noise nature to suggest the ways to reduce it.

This letter describes an implementation of micromachined seismometer based on molecular electronic transducer (MET) technology. As opposed to a solid inertial mass, MET seismometer senses the movement of liquid electrolyte relative to fixed electrodes. The employment of micro-electro-mechanical systems techniques reduces the internal size of the sensing cell to 1 lm and improves the reproducibility of the device. For operating bias of 600 mV, a sensitivity of 809 V=ðm=s 2 Þ was measured under acceleration of 400 lgðg 9:81 m=s 2 Þ at 0.32 Hz. A À115 dB (relative to ðm=s 2 Þ= ffiffiffiffiffi ffi Hz p) noise level at 1 Hz was achieved. This work develops an alternative paradigm of seismic sensing device with small size, high sensitivity, low noise floor, high shock tolerance, and independence of installation angle, which is promising for next generation seismometers for planetary exploration. V

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This paper describes the use of MET-based low-noise angular motion sensors to precisely determine azimuth direction in a dynamic-scheme method of measuring the Earth’s rotational velocity vector. The scheme includes sensor installation on a rotating platform so that it could scan the space and seek for the position of the highest Earth’s rotation vector projection on its axis. This method is very efficient provided a low-noise sensor is used. A low-cost angular sensor based on MET (molecular electronic transduction) technology has been used. The sensors of this kind were originally developed for seismic activity monitoring and are well known for very good noise performance and high sensitivity. This approach, combined with the use of special signal processing algorithms, allowed reaching the accuracy of 0.2°, while the measurement time was less than 100 seconds.

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