Strapdown Associates, Inc.

4727 South Lake Sarah Drive

 Maple Plain, Minnesota 55359

 Phone:  (763) 479-1918     Ground Line Fax:  (763) 479-1476

 email:  [email protected]

Paul G. Savage - President  - Resume Professional ActivitiesPublications Through April 2024

Strapdown Associates, Inc. (SAI) is an independent Minnesota corporation founded in 1980.  SAI provides engineering consulting and educational services to aerospace companies and government agencies for design and test of aided and unaided strapdown inertial navigation systems

Website Contents

Paul G. Savage Books

Paul G. Savage Free-Access Articles

Strapdown Humor

Note: Some of the files linked from this web are in pdf format.  Translating the files requires Adobe Acrobat Reader which can be downloaded for free from the following website: http://www.adobe.com/products/acrobat/readstep2.html

SPECIAL NOTE - PDF COPIES OF PAUL G SAVAGE'S BOOKS (STRAPDOWN ANALYTICS II AND
      STRAPDOWN-NAV COURSE BOOKS) ARE NOW AVAILABLE FOR FREE ON THIS WEBSITE
        - SEE BELOW

STRAPDOWN ANALYTICS II

The second edition of Strapdown Analytics by Paul G Savage, is a detailed comprehensive tutorial of the author's knowledge in all analytical aspects of unaided and Kalman filter aided strapdown inertial navigation.  This includes not only the algorithms implemented in the strapdown system computer, but the analytics associated with system validation, test, simulation, and performance analysis.  Equations are derived from basics including intermediate steps, avoiding the common practice of referencing supporting equations to other source material.  This is not a simple book.  It covers some complicated analytical subjects.  Nevertheless, it has been designed for engineering analysts or graduate students having only a basic working knowledge of vector calculus and matrix operations.  Previous background in inertial navigation or navigation in general is not required.  The contents are summarized in the book's Table of Contents and in Chapter 1: Strapdown Analytics II - Table of Contents, Chapter 1

Errata For Strapdown Analytics I

Errata For Strapdown Analytics II Through April 2020

Strapdown Analytics II pdf Version Availability

SAI has now made a pdf version of Strapdown Analytics II available for free to all who want it.  To get your free pdf copy of Strapdown Analytics II Parts 1 or 2, click pdf1 or pdf2 .

INTRO-TO-STRAPDOWN-NAV COURSE BOOKS

From 1981 to 2009, SAI provided its four and a half day Introductory Course On Strapdown Inertial Navigation Systems to the general public in Minneapolis-Minnesota and on-site at contracting host facilities.  Books used in the course were: Introduction To Strapdown Inertial Navigation Systems (the "Yellow Book") and "Strapdown Inertial Navigation Lecture Notes" (the "Blue book").

Introduction To Strapdown Inertial Navigation Systems - This 712 page "Yellow Book" contains the Introductory Course presentation slides with accompanying detailed text descriptions.  SAI has now made a current pdf version of the Yellow Book  available for free to all who want it.  To get your free Yellow Book pdf copy, click pdf3.

Strapdown Inertial Navigation Lecture Notes - This 376 page reformatted "Blue Book" provides descriptions of strapdown inertial sensors and derivations of key equations presented in the Intro-to-Strapdown-Nav course.  SAI has now made a current pdf version of the Blue Book available for free to all who want it.  To get your free Blue Book pdf copy, click pdf4.

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Paul G. Savage Free-Access Technical Articles Available At This Website

 Free Access Articles Prepared For This Website - Although every effort has been made to eliminate errors in the following Free Access articles, it is inevitable that some errors will pass undetected.  If readers plan to use the technical material for engineering projects, they are encouraged to re-verify the material by analytical means and simulation

Recently Posted Articles At This Website

"Fiber Optic Compared To Ring Laser Optical Gyros", SAI WBN-14034, April 22, 2024

"Analytical Description Of Optical Gyros", SAI WBN-14024, April 3, 2019, Updated November 6, 2022 and March 15, 2024

"Simplified Description Of Optical Gyros - A Rigorous Analytical Development Without Vector Calculus", SAI WBN-14027, May 23, 2020, Updated March 8, 2024

"High Speed Outputs From A Strapdown IMU For Two-Speed Attitude/Velocity Updating In A Central Computer", SAI WBN-14033, April 1, 2023

"Inertial Sensor Stability Evaluation By Dual Sensor Testing", SAI WBN-14032, January 23, 2023

"Why Optical And Mechanical Gyros Measure The Same Angular Rate Relative To Non-Rotating Inertial Space", SAI WBN-14031, December 21, 2022

"Blazing Gyros - The Presentation", SAI WBN-14030, December 14, 2022

"Redefining Gravity And Newtonian Natural Motion", SAI WBN-14002, May 21, 2014, Updated September 28, 2022

Selected Previously Published Articles Formatted For Web Access

"Improved Strapdown Inertial Measurement Unit Calibration Procedures", SAI WBN-14028, June 2, 2020

"Performance Analysis Of Strapdown Systems", SAI WBN-14011, June 2, 2015

"Computational Elements For Strapdown Systems", SAI WBN-14010, May 31, 2015

"Blazing Gyros - The Evolution Of Strapdown Inertial Navigation Technology For Aircraft", SAI WBN-14009, May 29, 2015

        INERTIAL NAVIGATION AND GRAVITY

"High Speed Outputs From A Strapdown IMU For Two-Speed Attitude/Velocity Updating In A Central Computer", SAI WBN-14033, April 1, 2023

"Redefining Gravity And Newtonian Natural Motion", SAI WBN-14002, May 21, 2014, Updated September 28, 2022

"Modern Strapdown Attitude Algorithms And Their Accuracy, Versus Accuracy Requirements For Unaided Strapdown Inertial Navigation", SAI WBN-14025, February 9, 2020

"Down-Summing Rotation Vectors For Strapdown Attitude Updating", SAI WBN-14019, July 16, 2017

"Skewed Sensor Failure Detection Using Parallel Navigation Solutions", SAI WBN-14017, June 16, 2016

"Coarse Leveling Of INS Attitude Under Dynamic Trajectory Conditions", SAI WBN-14007, January 29, 2015

"Schuler Oscillations", SAI WBN-14003, June 27, 2014

                         INERTIAL SENSORS

"Fiber Optic Compared To Ring Laser Optical Gyros", SAI WBN-14034, April 22, 2024

"Inertial Sensor Stability Evaluation By Dual Sensor Testing", SAI WBN-14032, January 23, 2023

"Why Optical And Mechanical Gyros Measure The Same Angular Rate Relative To Non-Rotating Inertial Space", SAI WBN-14031, December 21, 2022

"Blazing Gyros - The Presentation", SAI WBN-14030, December 14, 2022

"Simplified Description Of Optical Gyros - A Rigorous Analytical Development Without Vector Calculus", SAI WBN-14027, May 23, 2020, Updated March 8, 2024

"Analytical Description Of Optical Gyros", SAI WBN-14024, April 3, 2019, Updated November 6, 2022 and March 15, 2024

"Digital Integration Algorithm Error For Band-Limited Random Process Inputs", SAI WBN-14018, June 26, 2017

"Fixed Gain Digital Filter Design For Specified Phase Versus Frequency Response", SAI WBN-14004, June 29, 2014

                  KALMAN INERTIAL AIDING

 

"Designing An Extended Kalman Filter For A Stellar Aided Strapdown Inertial Attitude Reference", SAI WBN-14012, January 16, 2016

"Lever Arm Corrections During INS Transfer Alignment With Wide Angle Initial Heading Error", SAI WBN-14008, April 17, 2015 (Updated 09/05/16)

"Moving Base INS Alignment With Large Initial Heading Error", SAI WBN-14006, October 3, 2014

"Modifying The Kalman Filter Measurement To Mitigate Second Order Amplification In INS Velocity Matching Alignment Applications", SAI WBN-14005, July 15, 2014

"Mitigating Second Order Error Effects In Linear Kalman Filters Using Adaptive Process And Measurement Noise", SAI WBN-14001, May 16, 2014

system simulation and calibration testing

 

"Generating Strapdown Specific-Force/Angular-Rate For Specified Attitude/Position Variation From A Reference Trajectory", SAI WBN-14026, April 21, 2020

"Appendices F, G, And H to Generating Strapdown Specific-Force/Angular-Rate For Specified Attitude/Position Variation From A Reference Trajectory", SAI WBN-14026a, April 21, 2020

"Improved Strapdown Inertial System Calibration Procedures - Part 1 - Procedures And Accuracy Analysis", SAI WBN-14020-1, October 20, 2017 (Updated January 11, 2018)

"Improved Strapdown Inertial System Calibration Procedures - Part 2 - Analytical Derivations", SAI WBN-14020-2, October 20, 2017  (Updated January 11, 2018)

"Improved Strapdown Inertial System Calibration Procedures - Part 3 - Numerical Examples", SAI WBN-14020-3, November 10, 2017 (Updated January 11, 2018)

                                  relativity

 

"Differential Point-To-Point Relativity In Rotating Coordinates", SAI WBN-14022, May 28, 2018 (Updated November 5, 2018)

"Differential Kinematics Of Point-To-Point Relativity", SAI WBN-14021, March 11, 2018

"Introduction To The Kinematics Of Point-To-Point Relativity", SAI WBN-14015, April 17, 2016 (Updated May 3, 2018)

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Strapdown Humor

"Blazing Gyros - The Movie (Early Preview)", SAI WBN-14016, May 25,2016

"Geordie's Quaternion Decision", SAI WBN-14014, February 17, 2016

"Program Management", SAI WBN-14013, January 18, 2016

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