Automotive applications are known to impose quite harsh environmental conditions such as vibration, shock, temperature, and thermal cycling on inertial sensors. Micromachined gyroscopes are known to be especially challenging to develop and commercialize due to high sensitivity of their dynamic response to fabrication and environmental variations. Meeting performance specifications in the demanding automotive environment with low-cost and high-yield devices requires a very robust microelectromechanical systems (MEMS) sensing element. This paper reviews the design trend in structural implementations that provides inherent robustness against structural and environmental parameter variations at the sensing element level. The fundamental approach is based on obtaining a gain and phase stable region in the frequency response of the sense-mode dynamical system in order to achieve overall system robustness. Operating in the stable sense frequency region provides improved bias stability, temperature stability, and immunity to environmental and fabrication variations.

/pdf/environmentally-robust-mems-vibratory-gyroscopes-for-3eqfmhu8sq.pdf

Environmentally Robust MEMS Vibratory Gyroscopes for Automotive Applications

An indoor localization and communication project is described that proposes to use RFID (radio-frequency identification) tags, placed in the building beforehand, as navigation waypoints for an inertial navigation system carried by a first responder. RFID devices commonly are attached to persons or to moveable objects so that the objects can be tracked by using fixed readers (special-purpose radio receivers) at different locations. In this project, we explore the "flip side" of this practice. Our concept is that detection of RFID devices in known, fixed locations by a moving reader provides a precise indication of location for tracking the person or moving object that is carrying the reader. This information can then be used to correct for any errors of an inertial tracking system.

/pdf/rfid-assisted-indoor-localization-and-communication-for-2889iiahng.pdf

RFID-assisted indoor localization and communication for first responders

GPS is the most widely used global navigation satellite system. By design, there is no provision for real time integrity information within the Standard Positioning Service (SPS). However, in safety critical sectors like aviation, stringent integrity performance requirements must be met. This can be achieved externally or at the receiver level through receiver autonomous integrity monitoring (RAIM). The latter is a cost effective method that relies on data consistency, and therefore requires redundant measurements. An external aid to provide this redundancy can be in the form of an Inertial Navigation System (INS). This should enable continued performance even during RAIM holes (when no redundant satellite measurements are available). However, due to the inclusion of an additional system and the coupling mechanism, integrity issues become more challenging. To develop an effective integrity monitoring capability, a good understanding of the potential failure modes of the integrated system is vital. In this paper potential failure modes of integrated GPS/INS systems are identified. This is followed by the specification of corresponding models that would be required to investigate the capability of existing integrity algorithms and to develop enhancements or new algorithms.

https://www.cambridge.org/core/services/aop-cambridge-core/content/view/S0373463307004237

Failure modes and models for integrated GPS/INS systems

In the early 1990s, Systron Donner Inertial Division (SDID), a subsidiary of BEI Technologies, Inc., possessed a new solid-state rate gyroscope technology that had not yet matured or captured a significant market share. Even though some success had been achieved in defense missile applications, a strategy was clearly needed to further develop the technology and lay the foundation for future growth. The strategy search led to discovery of a leading edge automotive brake system application, which, in turn, led to a radical change in design and manufacturing approaches, as well as a dramatic increase in revenues. The resultant radical cost-reduction of quartz rate sensor (QRS) components has benefit for both the automotive and the aerospace and defense (A&D) applications. Commonality of design and design techniques is leveraging high-volume, low-cost automotive components into low-volume A&D products.

Common design techniques for BEI GyroChip quartz rate sensors for both automotive and aerospace/defense markets

...........................................................................................................................iii Acknowledgements .........................................................................................................vii Table of

Improved integrity algorithms for integrated GPS/INS systems in the presence of slowly growing errors

A Quartz Rate Sensor (QRS) family based on the Coriolis effect is presented. The architecture is highly capable of detecting internal failures. The MEMS solid-state rate gyro (known by the trade name GyroChip/sup (R)/) consists of a third generation microminiature double-ended quartz tuning fork, as well as third generation electronics in the form of a mixed signal ASIC. The high reliability device has no wearout mechanisms and features a micromachined sensing element. The sensor requirements, theory of operation, architecture, packaging family and performance parameters are described. In addition, system safety considerations and a description of the comprehensive self-monitoring features are provided.

A.M. Madni

Papers

A third generation, highly monitored, micromachined quartz rate sensor for safety-critical vehicle stability control