Gyros and accelerometers are the key components in Inertial Navigation Systems (INS). Until recently the size and weight of a high performance INS’s has been dominated by the size of the gyros. This is now slowly changing, at least for tactical grade performance INS’s. This is due to the evolution of MEMS gyro technology. Imego is a leading developer of MEMS gyros, making a major contribution to the technology that is pushing this field forward. Furthermore, Imego people have been actively involved in the development of MEMS gyros for over a decade. For several years, Imego has been developing a unique digital electronics gyro platform “GyroSense” that, together with SensorNor’s Butterfly Gyro element (SW510), becomes the Imego Butterfly Gyro 2.0 (IBG20). Today, it is standard in all new INS and motion trackers from Imego. This proprietary gyro sensor features noise levels as low as 0.003 deg/s/sqrt(Hz) and an offset stability of 1 deg/hr or below in its best samples. This is up to 50 times better than the performance of our earlier gyro systems with analog electronics, translating to dramatic navigation performance improvements. This new generation IBG20 gyro is actually so good it is able to measure the earth rate (15 °/hour), an undisputable quality measure for a gyro. It shows that the gyro has both high resolution (low noise) and high stability. To understand more fully how small this rate is, one can make a comparison with the speed of the hour dial on a watch; it moves with twice the earth rate. Thus, the rate that we measure is half the rate of the hour pointer on a watch. All this is achieved with a gyro chip that is only 3X3X2 mm.
Imego’s inertial systems and components (gyros and accelerometers) target demanding professional as well as industrial and military applications. Most of our customers are not buying just a gyro or an accelerometer. Instead, together with the customer, a novel application is developed, made possible by our unique sensors. One recent example of this is a tool for measuring drilled holes that is now in production. It was not possible to build such an instrument previously due to fact that the components that could deliver sufficient performance were too large.
Imego’s Butterfly gyro is a patented MEMS sensor that measures angular rate. The gyro is manufactured in mono-crystalline silicon and is combined with extremely flexible electronics that can be tailored for a wide range of different application. The figure below shows the architecture of the IBG20. It consists of three parts: the Butterfly gyroscopic sensing element, a programmable digital ASIC, and an FPGA circuit. The butterfly gyroscopic sensing element is commercially manufactured and sold by SensoNor of Norway under the name SAR10. The programmable digital ASIC is developed at Imego and manufactured by Chartered Semiconductor Manufacturing of Singapore. It contains all the necessary circuitry for excitation and readout of capacitive/electrostatic gyroscopes. The gyro and ASIC is mounted in a ceramic LCC28 package. The feedback loops and the signal extraction are implemented in software algorithms within an FPGA circuit, allowing for a great amount of flexibility. A schematic block diagram of the IBG20 (Imego Butterfly Gyro 2.0).  The ASIC contains low-noise readout amplifiers and sigma-delta modulators that convert signals to the digital domain. This concept is novel in that the feedback loops are implemented in the digital domain, allowing the sensor to be easily tailored for specific applications. Finally, the use of digital signal processing gives much improved low-frequency noise performance. For more information about what the IBG20 can do for your application, please contact our sales team. |