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Figure

1. SIM’s Symmetrical Resonating Gyroscope

*Best to Date

MEMS Symmetrical Resonating

Gyroscope Brief

INTRODUCTION

Sensors in Motion has created the world’s first MEMS

(Micro-Electro-Mechanical System) based navigation grade gyroscope. Our Symmetrical Resonating Gyroscopes (SRG) deliver drift less than 0.01 deg/hr and ARW less than 0.005 deg/rt-hr. Current high performance inertial technology is dominated by inertial measurement units (IMUs) employing large, expensive and power hungry ring laser gyroscopes (RLGs) or fiber optic gyroscopes (FOGs). Optical gyros suffer from dead-band non-linearity’s and light source life issues as well. MEMS devices achieved via low cost, batch fabrication methods have the cost, size, weight and power reduction to benefit augmented GPS, down-hole drilling, dead-reckoning, autonomous vehicles, platform stabilization and a myriad of strategic defense and commercial capabilities.

THEORY OF OPERATION

The SRG operates on two modes. A set of DC bias electrodes are used to tune the resonator using electrostatic spring softening on its two degenerate oscillation modes to become near perfect degeneracy in frequency. A sinusoidal voltage is applied to its first set of electrode to excite its ring structure into oscillation. The second mode is then excited by the Coriolis force, sensed and fed into amplifiers to nullify the

transferred vibrational energy. The rotation rate can then be extracted from the feedback voltage used for suppression as they are directly proportional to one another.

DESIGN AND PERFORMANCE

Fifteen years of development starting at NASA’s famed Jet Propulsion Labs and over 20 patents has led to the highest performing MEMS gyroscope in the world. With sensor volume less than 35 mm 3 the SRG surpasses all other MEMS and most traditional gyros in proven performance through its unique design. The co-etched resonator/electrode structure of the SRG efficiently maximizes use of the area of the sensor to increase sensing capacitance, thus increasing its signal-to-noise ratio. Its centrally mounted resonator supports two degenerate elastic inertial waves for Coriolis sensing result in a very stable mechanical quality factor, limited only by

material damping. The axially

symmetric design of the SRG

and its single nodal support ensures minimal coupling to package stresses eliminating

anchoring losses and enables the device to survive over 2000g shock. SIM’s SRG specification, and comparison

is shown.

High Performance Gyro Bias

Stability ( o/hr )

Angle Random Walk ( o/√hr) NonLinearity (ppm) Bandwidth

(Hz) Top

Competitors

3 0.1 1000 55 SIM SRG’s 0.2 0.061 10 100 0.05 0.009 10 100

0.01 0.005 10 100

0.003* 0.002* 10 100 Table I. SIM SRG vs Top Competitors

10

101010

4

10

-3

10

-2

10

-1

10

10

1

Integration Time (sec)

R a t e A l l a n D e v i a t i o n (d e g /h r )

Note; Some or all of SIMs SRG’s may be ITAR controlled.

Parameter

Conditions Min Max Units Number of Sensing Axes 1

Axis Measurement Range Full-Scale Range

-700

+700 o/sec Angular Acceleration Range

1000 o/sec 2 Gyro Fixed Bias < 100 o/hr Gyro Bias Repeatability 0.1 o/hr turn-on to turn-on

1 Gyro Bias Stability in-run < 0.0

2 o/hr Angle Random Walk

0.005 o/√hr Noise Density

in-run 0.03 o/hr/√Hz Gyro Scale Factor Error

50 ppm Gyro Scale Factor Stability in-run

10 ppm Gyro Axis Alignment Error

0.1 μrad Gyro g-Sensitivity 0.5 o/hr/g Gyro g 2-Sensitivity

0.05 o/hr/g 2Bandwidth 100 Hz Temperature Bias 1 o/hr/ oC Temperature Coefficient ±20 ppm/ oC

Shock Survivability

2000

g

Table II. SIM SRG 5000 Specifications

Figure 2. Allan Deviation Plot of a SIM SRG

Figure 2 above shows the green chart of a SIM’s SRG gyroscope with a bias instability of 0.0045 o/hr and an angle random walk of 0.0029 o/√hr. Figure 3 to the right shows a comparison of variations of SIM’s SRGs versus a top competitor**.

Figure 3.SIM SRG vs Competitor’s**Green Chart

(Source: From Product’s Datasheets)

PERFORMANCE COMPARISON

Inertial Measurement Unit

SIM has incorporated its Symmetrical Resonating Gyroscope into a 6 DOF north finding IMU. The prototype is the world’s first Navigation Grade MEMS INS ever produced and leads our technology roadmap to a 1.5 in 3 system.

CONTACT

Product (TYPE) Bias Instability (°/hr) Angle Random Walk (°/hr/√

Hz)

NonLinearity (% of FS)

Temperature Coefficient (%of FS/°C)

Temperature Bias

(°/hr/°C)

Bandwidth

(Hz)

Shock Survivability

(g)

SIM SIM500 (MEMS) 0.05

0.005

0.005

0.002

1

100

2000 Silicon Sensing CRS09-11 (MEMS) 3 0.1 0.1 1 3600 55

Do not drop exceeding 300mm Sensonor STIM300 (MEMS) 0.5 0.15 0.005 N/A 5 262

1500

Analog Devices ADIS16137 (MEMS) 2.8 0.15 0.05 0.004 4.5 400 2000

ST Micro LY330ALH (MEMS) N/A 50.4 1 0.01 72 140 3000

Emcore EMP-1.2K (FOG) 0.01 0.002 0.0025 N/A N/A 500 N/A

Northrup Grumann LN200 (FOG) 2 0.11 N/A N/A N/A N/A 90

Honeywell HG1900 (MEMS)

1 0.06 N/A N/A N/A

N/A N/A

Lab and Testing Facility: Goleta, CA

Mailing Address (Headquarters): Sensors in Motion

505 Broadway E #124 Seattle, WA 98102

Contact:

info@https://www.sodocs.net/doc/c28161961.html,

Table III. Product Comparison of High Performance Gyroscopes and IMUs