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MEMS gyrometer for wing behaviour measurement

Final Report Summary - CS-GYRO (MEMS gyrometer for wing behaviour measurement)

Executive Summary:
The objective of this project has been to design a MEMS gyroscope for Smart Fixed Wing Aircraft purposes. This is a high-end application, stemming from its noise and stability requirements. Gyros with more than sufficient technical performance to meet this application’s specification have long been on the market. However, they employ technologies that make them less than suitable for this application in terms of cost, size, weight, power consumption or reliability. Consequently, silicon based MEMS is the technology of choice for this application. The STIM210-B gyroscope from Sensonor available in the market is the main outcome of the project. The performance of this device meets the specifications from the Clean Sky project and Sagem.

Project Context and Objectives:
The specifications for the gyro to be met according to the call-text were:
• Long-term stability including thermal modelling residue < 100 deg/h
• Short-term stability on 2 min including thermal modelling residue < 10 deg/h
• Noise < 0.1 deg/s over 0 to 100 Hz
• Bandwidth: 100 to 150 Hz
• Rate range: 100 to 500 deg/s
The STIM210-B gyroscope from Sensonor available in the market is the main outcome of the project. The performance of this device meets the specifications from the Clean Sky project and Sagem.

Project Results:
STIM210 is a cluster of 1, 2 or 3 high accuracy MEMS-based gyros in a miniature package. Any configuration of axes can be provided. Each axis is factory-calibrated for bias, sensitivity and compensated for temperature effects to provide high-accuracy measurements in the temperature range -40°C to +85°C. The unit runs off a single +5V supply.
STIM210 communicates via a standard high-level RS422 interface. The use of a 32 bit RISC ARM microcontroller provides flexibility in the configuration, like choice of output unit, sample rate, LP filter -3dB frequency and RS422 bitrate and protocol parameters. All configurable parameters can be defined when ordering or set by customer.
When STIM210 is powered up, it will perform an internal system check and synchronise the gyros. As an acknowledgement of the complete power-up sequence, it will provide special datagrams containing data, like part number, serial number, number of active axis and configuration parameters as mentioned above. STIM210 will then automatically proceed to provide measurement data. Connect power and STIM210 will provide accurate gyro measurements over the RS422 interface without any interaction with the device.
The measurement data is transmitted as packages of data on a fixed format (datagram) at intervals given by the sample rate. The datagram is in binary coded format in order to have an efficient transfer of data. In addition to the measurement data itself, the datagram contains an identifier, a status byte and a CRC (Cyclic Redundancy Check) byte to provide high degree of fault detection in the transmissions. The status byte will flag any detected errors in the system.
For more advanced users, the gyro may be put in Service Mode. In this mode all the configuration parameters can be intermediately or permanently changed by overwriting the current settings in the flash memory. In Service Mode the commands and responses are in a human readable format; to enable the use of terminal-type software during typical product integration. Service Mode also provides the ability to perform single measurements, perform diagnostics and obtain a higher detail level of detected errors reported in the status byte.

Main features for the STIM210 gyro are:
• Miniature package
• Low noise
• Low bias instability
• Excellent performance in vibration and shock environments
• 1, 2 or 3 axes offered in same package
o Electronically calibrated axis alignment
• Single-crystal silicon technology
o No intrinsic wear-out effects
• Insensitive to magnetic fields
• Full EMI compliance
• Digital interface, RS422
• Fully configurable:
o 5 different sample rates
o 5 different bandwidths
o LP filter -3dB frequency can be set individually for each axis
o RS422 protocol, bit-rate and line termination
o Selectable output unit: angular rate [deg/s], incremental angle [deg], average angular rate [deg/s] or integrated angle [°]
• External Trigger input and Time Of Validity output to enable synchronization
• Continuous self-diagnostics

Potential Impact:
The STIM210-B gyroscope from Sensonor available in the market is the main outcome of the project. The performance of this device meets the specifications from the Clean Sky project and Sagem. Results has been presented at conferences and published in relevant symposiums and exhibitions.

Sensonor’s business strategy is to make a difference in the industrial sensor and transducer community by focusing on products based on MEMS technology, but for High Precision applications. This is in contrast to traditional MEMS suppliers focusing on automotive and consumer applications. Based on more than 25 years history within the global MEMS industry and more than 250 million pressure sensors, more than 250 million accelerometers, and more than 2 million gyros shipped to customers for use in numerous type of applications and with a less than 0.1ppm field failure rate; it is the Sensonor’s devotion to serve customers with enabling solutions when the combination of size, performance and robustness matters. Unique designs for the inertial sensing dies guarantees unbeaten performance for demanding applications and for vibration exposed applications in particular. Our gyros close the gap to and represents a superior choice to FOG's in respect to robustness, reliability, size/weight, power and cost. In the same way our High Precision accelerometer will represent a superior choice to force-feedback quartz based state-of-art accelerometers like the QA2000 from Honeywell.

The STIM210 technology has been patented by Sensonor. The resulting STIM210 gyro product for the SFWA applications has a much broader targeted and total available market (TAM) outside commercial avionics. Also within the same segment, replacement of expensive and bulky solutions used for AHRS and other flight recorders are well worth to mention. Outside this segment, defence application within land, sea and air is by far the largest. Applications herein include missile-, rocket- and ammunition guidance and soldier navigation. Typical dual use applications count camera and platform stabilization and ROV and UAV navigation. Aerial-, land- and maritime survey and navigation equipment are important applications; e.g. directional drilling tools and geographical mapping equipment. All sorts of motion tracking depends on low noise inertial sensors; e.g. real-time tracking of rescue-, fire- and law enforcement teams. Autonomous and precision robots may rely on inertial sensors for tracking and guidance and stabilization. Sensonor’s targeted TAM for these products can easily reach more than $500M dependent upon definition.

List of Websites:

Sensonor AS
Knudsrødv 7
P.O.Box 1004
3194 Horten