GPS has transformed navigation but unfortunately does not work in indoor or dense urban environments. The alternative, inertial navigation, is either too inaccurate or too large, power hungry, and costly in all but niche applications.
Gyroscopes are responsible for direction in inertial sensors. Since even small angular offsets can rapidly add up to large location errors, significantly improved gyroscope accuracy is the key to precise indoor navigation.
I will describe a prototype gyroscope with tactical grade performance. Unlike state-of-the-art solutions, the device does not rely on exotic fabrication technology or trimming, and both its size and power dissipation are comparable to existing mobile solutions.
How is this possible? Sensors, in general, compare their input to a reference. A thermometer compares its input to a reference temperature and reports the ratio. Gyroscope sensors have a huge advantage: their input is rate, degrees per second, also known as frequency. Frequency is the physical quantity that we can synthesize and measure with highest accuracy. While ppm-level precision is out-of-the-question for most properties, it is easily achieved for frequency.
Why then are gyroscopes not just as accurate as frequency sources? Oddly, present MEMS gyroscopes immediately turn frequency into force, then displacement, capacitance, voltage. Not only are these quantities difficult to measure with high accuracy, the scaling factors of all these transformations are subject to a myriad of fabrication and environmental variations. Not surprising that present gyroscopes suffer from a few errors.
The path to good gyroscopes is to measure frequency directly, without performance compromising detours. In this presentation, I will show you how.
The EE310 seminar series is intended to offer students a window onto the research directions of the SystemX industrial affiliates and associated faculty.
Offers a series of talks covering emerging topics in contemporary hardware/software systems design. Attention will be paid to the key building blocks of sensors, processing elements and wired/wireless communications, as well as their foundations in semiconductor technology, SoC construction, and physical assembly as informed by the SystemX Focus Areas. The series will draw upon distinguished engineering speakers from both industry and academia who are involved at all levels of the technology stack and the applications that are only now becoming possible.
- April 13: Tactical Grade Gyro in a Consumer Grade Process Bernhard Boser (UC Berkeley)
- April 20: Wi-Fi The R/Evolution Continues Sundar Sankaran (Ruckus)
- April 27: Secrets of Successful Technology Start-ups Paul Franklin (Independent)
- May 04: Dynamics of Exponentials in Circuits and Systems Ahmad Bahai (TI)