20 Years of KVH Fiber Optic Gyro Technology:

The Evolution from Large, Low Performance FOGs to Compact, Precise FOGs and FOG-based Inertial Systems

Presented by:Jay NapoliVice President, FOG and Inertial Systems SalesKVH Industries

KVH Industries Overview• Innovative technology company, ~ 600 employees worldwide

– Focused on mobile products and services– Addressing large markets

• Guidance & stabilization systems – Fiber optic gyros and navigation systems

• Mobile broadband satellite services– Global high-speed Internet, television, and voice

Guidance & Stabilization• Leading manufacturer of inertial navigation systems

– Based on our fiber optic gyro technology

• Military vehicle navigation systems• Majority of FOG sales non-defense• Exciting emerging applications

for FOGs– Self-driving cars– Autonomous vehicles– Drones– Gimbals

An Emerging, Evolving Technology• FOGs and FOG-based IMUs have become critical components within an

expanding array of platforms and applications

KVH Fiber Optic Gyro Solutions• Fiber Optic Gyros (FOGs)

– Versatile, stand-alone 1, 2, and 3 axis sensors– Compact, rugged, solid-state – Used in a broad range of applications / systems

• Inertial Measurement Units (IMUs)– Combines 3 axes of FOGs & 3 accelerometers – 6-degrees of freedom (1775 IMU is 9 DoF)– Low-cost, highly reliable solutions

• Inertial Navigation Systems (INS)– Combines an IMU with a GNSS receiver, pressure sensor and magnetometers– Comprehensive navigation/positioning with or without satellite availability – Full position, velocity & attitude sensing – AHRS

How Did We Get Here?• 20-year development and performance history

– The Andrew Corporation – Orland Park, IL– Proprietary D-shaped optical fiber, with an elliptical core – Revolutionary ThinFiber – Innovative optical circuit design, component fabrication, and system integration– Patented Digital Signal Processing (DSP) for improved performance

• A commitment to design, control, and quality at every step – Tactical-grade performance– Excellent reliability– Compact designs– Reasonable cost

• More than 90,000 FOGs produced

An End-to-End Manufacturer• KVH fabricates 100% of its optical fiber and

fiber components• We undertake all aspects of FOG manufacture:

– Drawing the fiber– Manufacturing optical components out of the fiber– Assembly of the optical circuit– Final integration and calibration with the FOG electronics

• Complete control and ensures the highest level of quality– ISO 9001 quality certified manufacturer– Complete traceability

KVH Open Loop Design

• KVH Open Loop Fiber Optic Gyros (FOGs)– Goal: Offer a more reliable, lower cost guidance & stabilization solution

RED: KVH-manufactured polarization-maintaining, elliptical core, single mode optical fiberGREEN: Printed circuit boards

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At the Heart of the FOG – Creating Fiber

Click to Watch a Brief Tour of the KVH Fiber Manufacturing Process

D-Shaped, Elliptical Core Fiber• Polarization maintaining fiber with unique design and core• Advantages include:

– High polarization maintaining ability (greater than 40 dB-m)– Low sensitivity to stress and temperature– Ideal for fiber splicing and pigtailing to other optical components– Maintains polarization and low-loss characteristics when exposed to physical stresses and

temperature-induced changes far better than PM fiber created using stress-induced birefringence

Superior Optical Qualities• D-shape fiber with elliptical core offers easy access to the light-guiding

region – Eliminates need for grinding or polishing

• Major axis of the elliptical core is parallel to the flat of the “D”– Allows accurate alignment of the birefringent axes

• The 1 x 3 micron elliptical core also aligns well with the 1 x 5 micron facet of the light source, as show below– Optimizes the core-to-facet alignment maximizes the power into the FOG’s optical circuit

The First Generation: 1997• E•Core 1000 and E•Core 2000

– Available in both analog and digital variants– Compact for their day– Moderate but solid performance

Attribute Specification SpecificationPerformance E•Core 1000 E•Core 2000Input Rotation Rate ± 100˚/sec ± 30, 60, or 100˚/sec

Angle Random Walk 0.3˚/√hr 0.08˚/√hrBias Instability ≤ 20˚/hr < 6˚/hrScale Factor Linearity 5,000 ppm 2,000 – 4,000 ppmPhysicalDimensions 4.3" x 3.3" x 1.6" (109mm x 84mm x 41mm) 4.41” x 4.27” x 1.69” (112mm x 108mm x 43 mm)

Weight 0.55 lbs. (0.25 kg) 0.75 lbs (0.34 kg)

The Shift to Digital Signal Processing• KVH’s patented DSP technology

– Optical output from the FOG is picked up at the detector and transformed into a voltage– Voltage is passed through an analog-to-digital converter– DSP approach permits analyzing and correcting this digitized data on the fly

• For Example: – KVH FOGs monitor their internal temperature and then compensate for temperature errors by using

a lookup table stored in memory

2003-2004: The DSP Family Emerges• Substantial improvement in performance in DSP line• Form factor roughly the size of a deck of cards

Attribute SpecificationPerformanceInput Rotation Rate ± 375˚/secAngle Random Walk ≤ 0.067˚/√hrBias Instability ≤ 1˚/hrScale Factor Linearity < 500 ppmPhysicalDimensions 3.5" x 2.3" x 1.3" (88.9mm x 58.4mm x 33mm)

Weight 0.6 lbs. (0.26 kg)

2009: Emergence of KVH’s ThinFiber• E•Core FOGs used optical fiber with diameter of ~240 microns• Most DSP FOGs use ThinFiber: a diameter of ~170 microns

– 30% less volume– Enables reduction in physical size of FOGs

• Maintain or improve performance overall vs. traditional E•Core fiber– A longer fiber length can be wound on a smaller bobbin, which translates into several improved

performance attributes

2009-2010: ThinFiber-based FOGs• The DSP-1750 introduced in 2009

– The world’s smallest high-performance FOG– Single- and dual-axis configurations

• Revolutionary performance levels for a unit its size– Input rates 5-10 times faster than original E•Core FOGs– Angle random walk (ARW) 5times better than DSP-3000 series– Bias stability is 8 times better than the DSP-3000 series– Performance on par with larger, more expensive closed-loop

fiber optic gyros and ring laser gyros

Attribute SpecificationPerformanceInput Rotation Rate ± 490˚/sec (standard) or ± 1000˚/secAngle Random Walk ≤ 0.013˚/√hrBias Instability ≤ 0.1˚/hrScale Factor Linearity < 200 ppmPhysicalDimensions 1.7" Dia x 0.9" H (45.7mm Dia x 22.9mm H )

Weight Single axis: 0.24 lbs (0.11 kg)

Dual axis: 0.30 lbs, (0.14 kg)

The DSP-1760: The Logical Progression• Available in 1-, 2-, or 3-axis configurations• Each FOG axis built using quadrupole winding• Improved software and algorithms• Higher processing power and improved

electronics

Attribute SpecificationPerformanceInput Rotation Rate ± 490˚/secAngle Random Walk ≤ 0.012˚/√hrBias Instability ≤ 0.05˚/hrSale Factor Linearity < 50 ppmPhysicalDimensions 3.5" Dia x 2.9" H (88.9mm Dia x 73.7mm H )

Weight Single axis: 1.1 lbs (0.5 kg)

Dual axis: 1.2 lbs, (0.54 kg)

3-axis: 1.3 lbs (0.60 kg)

2012: Expanding Capabilities with High-performance Fully Integrated Systems• KVH high-performance FOGs ideally suited for

higher level of integration within inertial systems• The 1750 IMU introduced in 2012:

– E•Core ThinFiber – Very low noise, solid state MEMS accelerometers– A commercial-off-the-shelf IMU

• KVH’s 1750 IMU provides:– Highly accurate 6-DOF angular rate and acceleration data– Bias instability: <0.05degrees/hr– A cylindrical package that measures only 89 mm diameter x 74 mm high

(3.5" in diameter x 2.9" high)– Weight of <0.6 kg (less than 1.4 lbs)

• Two additional performance variants: 1725 IMU and 1775 IMU

2016: Inertial Navigation Systems • GEO-FOG 3D and GEO-FOG 3D Dual

– 1750 IMU– 3-axis magnetometer– Barometric pressure sensor– Dual or triple frequency RTK GNSS receiver– Breakthrough sensor fusion algorithms

• automatically switch from loosely- to tightly-coupled filtering for improved performance under poor GNSS signal conditions

• What they deliver:– Reliable, real-time, centimeter-level positioning and orientation measurements– High-speed update rates– Rapid north-seeking gyrocompass capabilities– GEO FOG 3D Dual: Ideal for high-accuracy heading in environments when magnetometers and

GNSS-aided heading cannot be used

Where to Now: FOG and Integrated Inertial System Design• The creation and implementation of a continuous flow

manufacturing process– Eliminate the need for splicing optical components together– Improve performance– Reduce the manufacturing and calibration time required

• Continued research into smaller, more accurate FOGs and FOG-based systems

• Significant cost reductions via FOG design

The Next Challenges• The evolution of smaller, mass produced, low cost,

high-performance FOGs• Solutions that support mass markets, such as automotive• Provide a level of performance unmatched by

alternative gyro technology

KVH Industries, Inc.

www.kvh.com/imu