Global Navigation Satellite Systems, Inertial Navigation, and Integration - Mohinder S. Grewal - E-Book

Global Navigation Satellite Systems, Inertial Navigation, and Integration E-Book

Mohinder S. Grewal

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An updated guide to GNSS, and INS, and solutions to real-worldGNSS/INS problems with Kalman filtering Written by recognized authorities in the field, this thirdedition of a landmark work provides engineers, computer scientists,and others with a working familiarity of the theory andcontemporary applications of Global Navigation Satellite Systems(GNSS), Inertial Navigational Systems, and Kalman filters.Throughout, the focus is on solving real-world problems, with anemphasis on the effective use of state-of-the-art integrationtechniques for those systems, especially the application of Kalmanfiltering. To that end, the authors explore the various subtleties,common failures, and inherent limitations of the theory as itapplies to real-world situations, and provide numerous detailedapplication examples and practice problems, including GNSS-aidedINS (tightly and loosely coupled), modeling of gyros andaccelerometers, and SBAS and GBAS. Drawing upon their many years of experience with GNSS, INS, andthe Kalman filter, the authors present numerous design andimplementation techniques not found in other professionalreferences. The Third Edition includes: * Updates on the upgrades in existing GNSS and other systemscurrently under development * Expanded coverage of basic principles of antenna design andpractical antenna design solutions * Expanded coverage of basic principles of receiver design and anupdate of the foundations for code and carrier acquisition andtracking within a GNSS receiver * Expanded coverage of inertial navigation, its history, itstechnology, and the mathematical models and methods used in itsimplementation * Derivations of dynamic models for the propagation of inertialnavigation errors, including the effects of drifting sensorcompensation parameters * Greatly expanded coverage of GNSS/INS integration, includingderivation of a unified GNSS/INS integration model, itsMATLAB® implementations, and performance evaluation undersimulated dynamic conditions The companion website includes updated background material;additional MATLAB scripts for simulating GNSS-only and integratedGNSS/INS navigation; satellite position determination; calculationof ionosphere delays; and dilution of precision.

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Table of Contents

Cover

Title

Copyright

Dedication

PREFACE

ACKNOWLEDGMENTS

ACRONYMS AND ABBREVIATIONS

1 INTRODUCTION

1.1 NAVIGATION

1.2 GNSS OVERVIEW

1.3 INERTIAL NAVIGATION OVERVIEW

1.4 GNSS/INS INTEGRATION OVERVIEW

PROBLEMS

REFERENCES

2 FUNDAMENTALS OF SATELLITE NAVIGATION SYSTEMS

2.1 NAVIGATION SYSTEMS CONSIDERED

2.2 SATELLITE NAVIGATION

2.3 TIME AND GPS

2.4 EXAMPLE: USER POSITION CALCULATIONS WITH NO ERRORS

PROBLEMS

REFERENCES

3 FUNDAMENTALS OF INERTIAL NAVIGATION

3.1 CHAPTER FOCUS

3.2 BASIC TERMINOLOGY

3.3 INERTIAL SENSOR ERROR MODELS

3.4 SENSOR CALIBRATION AND COMPENSATION

3.5 EARTH MODELS

3.6 HARDWARE IMPLEMENTATIONS

3.7 SOFTWARE IMPLEMENTATIONS

3.8 INS PERFORMANCE STANDARDS

3.9 TESTING AND EVALUATION

3.10 SUMMARY

PROBLEMS

REFERENCES

4 GNSS SIGNAL STRUCTURE, CHARACTERISTICS, AND INFORMATION UTILIZATION

4.1 LEGACY GPS SIGNAL COMPONENTS, PURPOSES, AND PROPERTIES

4.2 MODERNIZATION OF GPS

4.3 GLONASS SIGNAL STRUCTURE AND CHARACTERISTICS

4.4 GALILEO

4.5 COMPASS/BD

4.6 QZSS

PROBLEMS

REFERENCES

5 GNSS ANTENNA DESIGN AND ANALYSIS

5.1 APPLICATIONS

5.2 GNSS ANTENNA PERFORMANCE CHARACTERISTICS

5.3 COMPUTATIONAL ELECTROMAGNETIC MODELS (CEMS) FOR GNSS ANTENNA DESIGN

5.4 GNSS ANTENNA TECHNOLOGIES

5.5 PRINCIPLES OF ADAPTABLE PHASED-ARRAY ANTENNAS

5.6 APPLICATION CALIBRATION/COMPENSATION CONSIDERATIONS

PROBLEMS

REFERENCES

6 GNSS RECEIVER DESIGN AND ANALYSIS

6.1 RECEIVER DESIGN CHOICES

6.2 RECEIVER ARCHITECTURE

6.3 SIGNAL ACQUISITION AND TRACKING

6.4 EXTRACTION OF INFORMATION FOR USER SOLUTION

6.5 THEORETICAL CONSIDERATIONS IN PSEUDORANGE, CARRIER PHASE, AND FREQUENCY ESTIMATIONS

6.6 HIGH-SENSITIVITY A-GPS SYSTEMS

6.7 SOFTWARE-DEFINED RADIO (SDR) APPROACH

6.8 PSEUDOLITE CONSIDERATIONS

PROBLEMS

REFERENCES

7 GNSS DATA ERRORS

7.1 DATA ERRORS

7.2 IONOSPHERIC PROPAGATION ERRORS

7.3 TROPOSPHERIC PROPAGATION ERRORS

7.4 THE MULTIPATH PROBLEM

7.5 METHODS OF MULTIPATH MITIGATION

7.6 THEORETICAL LIMITS FOR MULTIPATH MITIGATION

7.7 EPHEMERIS DATA ERRORS

7.8 ONBOARD CLOCK ERRORS

7.9 RECEIVER CLOCK ERRORS

7.10 SA ERRORS

7.11 ERROR BUDGETS

PROBLEMS

REFERENCES

8 DIFFERENTIAL GNSS

8.1 INTRODUCTION

8.2 DESCRIPTIONS OF LOCAL-AREA DIFFERENTIAL GNSS (LADGNSS), WIDE-AREA DIFFERENTIAL GNSS (WADGNSS), AND SPACE-BASED AUGMENTATION SYSTEM (SBAS)

8.3 GEO WITH L1L5 SIGNALS

8.4 GUS CLOCK STEERING ALGORITHM

8.5 GEO ORBIT DETERMINATION (OD)

8.6 GROUND-BASED AUGMENTATION SYSTEM (GBAS)

8.7 MEASUREMENT/RELATIVE-BASED DGNSS

8.8 GNSS PRECISE POINT POSITIONING SERVICES AND PRODUCTS

PROBLEMS

REFERENCES

9 GNSS AND GEO SIGNAL INTEGRITY

9.1 INTRODUCTION

9.2 SBAS AND GBAS INTEGRITY DESIGN

9.3 SBAS EXAMPLE

9.4 SUMMARY

9.5 FUTURE: GIC

PROBLEM

REFERENCES

10 KALMAN FILTERING

10.1 INTRODUCTION

10.2 KALMAN FILTER CORRECTION UPDATE

10.3 KALMAN FILTER PREDICTION UPDATE

10.4 SUMMARY OF KALMAN FILTER EQUATIONS

10.5 ACCOMMODATING TIME-CORRELATED NOISE

10.6 NONLINEAR AND ADAPTIVE IMPLEMENTATIONS

10.7 KALMAN–BUCY FILTER

10.8 HOST VEHICLE TRACKING FILTERS FOR GNSS

10.9 ALTERNATIVE IMPLEMENTATIONS

10.10 SUMMARY

PROBLEMS

REFERENCES

11 INERTIAL NAVIGATION ERROR ANALYSIS

11.1 CHAPTER FOCUS

11.2 ERRORS IN THE NAVIGATION SOLUTION

11.3 NAVIGATION ERROR DYNAMICS

11.4 INERTIAL SENSOR NOISE

11.5 SENSOR COMPENSATION ERRORS

11.6 SOFTWARE SOURCES

11.7 SUMMARY

PROBLEMS

REFERENCES

12 GNSS/INS INTEGRATION

12.1 CHAPTER FOCUS

12.2 GNSS/INS INTEGRATION OVERVIEW

12.3 UNIFIED MODEL FOR GNSS/INS INTEGRATION

12.4 PERFORMANCE ANALYSIS

12.5 OTHER INTEGRATION ISSUES

12.6 SUMMARY

PROBLEM

REFERENCES

APPENDIX A: SOFTWARE

A.1 SOFTWARE SOURCES

A.2 SOFTWARE FOR CHAPTER 3

A.3 SOFTWARE FOR CHAPTER 4

A.4 SOFTWARE FOR CHAPTER 7

A.5 SOFTWARE FOR CHAPTER 10

A.6 SOFTWARE FOR CHAPTER 11

A.7 SOFTWARE FOR CHAPTER 12

A.8 ALMANAC/EPHEMERIS DATA SOURCES

APPENDIX B: COORDINATE SYSTEMS AND TRANSFORMATIONS

B.1 COORDINATE TRANSFORMATION MATRICES

B.2 INERTIAL REFERENCE DIRECTIONS

B.3 APPLICATION-DEPENDENT COORDINATE SYSTEMS

B.4 COORDINATE TRANSFORMATION MODELS

B.5 NEWTONIAN MECHANICS IN ROTATING COORDINATES

INDEX

End User License Agreement

Guide

Cover

Table of Contents

Begin Reading

List of Tables

1 INTRODUCTION

TABLE 1.1.

U.S. Ground-Launched Missile Projects Begun in 1946

TABLE 1.2.

A Sampling of Inertial Sensor Types

2 FUNDAMENTALS OF SATELLITE NAVIGATION SYSTEMS

TABLE 2.1.

Example with Four Satellites

3 FUNDAMENTALS OF INERTIAL NAVIGATION

TABLE 3.1.

Performance Grades for Gyroscopes

TABLE 3.2.

INS and Inertial Sensor Performance Ranges

4 GNSS SIGNAL STRUCTURE, CHARACTERISTICS, AND INFORMATION UTILIZATION

TABLE 4.1.

Components of Ephemeris Data

TABLE 4.2.

Algorithm for Computing Satellite Position

TABLE 4.3.

Key Galileo Signals and Parameters

TABLE 4.4.

Key QZSS Signals and Parameters

7 GNSS DATA ERRORS

TABLE 7.1.

Representative Kalman Filter Parameter Values

8 DIFFERENTIAL GNSS

TABLE 8.1.

Worldwide SBAS System Coverage

TABLE 8.2.

Code-Carrier Coherence Results

TABLE 8.3.

Cases Used in Geometry-per-Station Analysis

9 GNSS AND GEO SIGNAL INTEGRITY

TABLE 9.1.

List of SBAS Error Sources

10 KALMAN FILTERING

TABLE 10.1.

Essential Kalman Filter Equations

TABLE 10.2.

Linearized Kalman Filter Equations

TABLE 10.3.

Extended Kalman Filter Equations

TABLE 10.4.

Kalman–Bucy Filter Equations

TABLE 10.5.

Vehicle Dynamic Models for GNSS Receivers

TABLE 10.6.

Filter Models for Unknown Vehicle Dynamics

TABLE 10.7.

Statistical Parameters of Host Vehicle Dynamics

TABLE 10.8.

Comparison of Alternative GNSS Filters on 1.5-km Figure-8 Track Simulation

TABLE 10.9.

Summary Implementation of Schmidt–Kalman Filter

TABLE 10.10.

Implementation Equations for Serial Measurement Update

TABLE 10.11.

Compatible Methods for Solving the Riccati Equation

11 INERTIAL NAVIGATION ERROR ANALYSIS

TABLE 11.1.

List of Symbols and Approximations

TABLE 11.2.

State Variables for the Nine Core INS Errors

TABLE 11.3.

Dynamic Coefficient Submatrix Sources

TABLE 11.4.

Equation References for Dynamic Coefficient Submatrices

APPENDIX B: COORDINATE SYSTEMS AND TRANSFORMATIONS

TABLE B.1.

Multiplication of Quaternion Basis Matrices

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GLOBAL NAVIGATION SATELLITE SYSTEMS, INERTIAL NAVIGATION, AND INTEGRATION

THIRD EDITION

MOHINDER S. GREWAL

ANGUS P. ANDREWS

CHRIS G. BARTONE

Copyright © 2013 by John Wiley & Sons, Inc. All rights reserved

Published by John Wiley & Sons, Inc., Hoboken, New Jersey

Published simultaneously in Canada

No part of this publication may be reproduced, stored in a retrieval system, or transmitted in any form or by any means, electronic, mechanical, photocopying, recording, scanning, or otherwise, except as permitted under Section 107 or 108 of the 1976 United States Copyright Act, without either the prior written permission of the Publisher, or authorization through payment of the appropriate per-copy fee to the Copyright Clearance Center, Inc., 222 Rosewood Drive, Danvers, MA 01923, (978) 750-8400, fax (978) 750-4470, or on the web at www.copyright.com. Requests to the Publisher for permission should be addressed to the Permissions Department, John Wiley & Sons, Inc., 111 River Street, Hoboken, NJ 07030, (201) 748-6011, fax (201) 748-6008, or online at http://www.wiley.com/go/permissions.

Limit of Liability/Disclaimer of Warranty: While the publisher and author have used their best efforts in preparing this book, they make no representations or warranties with respect to the accuracy or completeness of the contents of this book and specifically disclaim any implied warranties of merchantability or fitness for a particular purpose. No warranty may be created or extended by sales representatives or written sales materials. The advice and strategies contained herein may not be suitable for your situation. You should consult with a professional where appropriate. Neither the publisher nor author shall be liable for any loss of profit or any other commercial damages, including but not limited to special, incidental, consequential, or other damages.

For general information on our other products and services or for technical support, please contact our Customer Care Department within the United States at (800) 762-2974, outside the United States at (317) 572-3993 or fax (317) 572-4002.

Wiley also publishes its books in a variety of electronic formats. Some content that appears in print may not be available in electronic formats. For more information about Wiley products, visit our web site at www.wiley.com.

Library of Congress Cataloging-in-Publication Data:

Grewal, Mohinder S.

 Global navigation satellite systems, inertial navigation, and integration / Mohinder S. Grewal, Angus P. Andrews, Chris G. Bartone. – Third edition.

pages cm

 Includes index.

 Originally published under title: Global positioning systems, inertial navigation, and integration.

 ISBN 978-1-118-44700-0 (cloth);

 1. Global Positioning System. 2. Inertial navigation. 3. Kalman filtering. I. Andrews, Angus P. II. Bartone, Chris G. III. Title.

 G109.5.G74 2013

 910.285–dc23

2012032753

M.S.G. dedicates this book to the memory of his parents, Livlin Kaur and Sardar Sahib Sardar Karam Singh Grewal.

A.P.A. dedicates his contributions to his wife, Jeri, without whom it never would have happened.

C.G.B dedicates this work to his wife, Shirley, and two sons, Christopher and Stephen, for their never-ending support over the years.

PREFACE

This book is intended for people who need a working knowledge of global navigation satellite systems (GNSSs), inertial navigation systems (INSs), and the Kalman filtering models and methods used in their integration. The book is designed to provide a usable, working familiarity with both the theoretical and practical aspects of these subjects. For that purpose, we include “real-world” problems from practice as illustrative examples. We also cover the more practical aspects of implementation: how to represent problems in a mathematical model, analyze performance as a function of model parameters, implement the mechanization equations in numerically stable algorithms, assess the computational requirements, test the validity of results, and monitor performance in operation with sensor data from GNSS (GPS) and INS. These important attributes, often overlooked in theoretical treatments, are essential for effective application of theory to real-world problems.

The accompanying companion website (www.wiley.com/go/globalnavigation) contains MATLAB® m-files to demonstrate the workings of the navigation solutions involved. It includes Kalman filter algorithms with GNSS and INS data sets so that the reader can better discover how the Kalman filter works by observing it in action with GNSS and INS. The implementation of GNSS, INS, and Kalman filtering on computers also illuminates some of the practical considerations of finite-word-length arithmetic and the need for alternative algorithms to preserve the accuracy of the results. If the student wishes to apply what she or he learns, then it is essential that she or he experience its workings and failings—and learn to recognize the difference.

The book is organized for use as a text for an introductory course in GNSS technology at the senior level or as a first-year graduate-level course in GNSS, INS, and Kalman filtering theory and applications. It could also be used for self-instruction or review by practicing engineers and scientists in these fields.

This third edition includes advances in GNSS/INS technology since the second edition in 2007, as well as many improvements suggested by reviewers and readers of the second edition. Changes in this third edition include the following:

1.

 Updates on the upgrades in existing GNSS systems and on other systems currently under development

2.

 Expanded coverage of basic principles of antenna design and practical antenna design solutions

3.

 Expanded coverage of basic principles of receiver design, and an update of the foundations for code and carrier acquisition and tracking within a GNSS receiver

4.

 Expanded coverage of inertial navigation, its history, its technology, and the mathematical models and methods used in its implementation

5.

 Derivations of dynamic models for the propagation of inertial navigation errors, including the effects of drifting sensor compensation parameters

6.

 Greatly expanded coverage of GNSS/INS integration, including derivation of a unified GNSS/INS integration model, its MATLAB imple­mentations, and performance evaluation under simulated dynamic conditions

The accompanying website has also been augmented to include updated background material and additional MATLAB scripts for simulating GNSS-only and integrated GNSS/INS navigation. These routines include satellite position determination, calculation of ionospheric delays, and dilution of precision.

Chapter 1 provides an overview of navigation, in general, and GNSS and inertial navigation, in particular. These overviews include fairly detailed descriptions of their respective histories, technologies, different implementation strategies, and applications.

Chapter 2 covers the fundamental attributes of satellite navigation systems, in general, and the technologies involved, how the navigation solution is implemented, and how satellite geometries influence errors in the solution.

Chapter 3 covers the fundamentals of inertial navigation, starting with its nomenclature and continuing through to practical implementation methods, error sources, performance attributes, and development strategies.

Chapters 4–9 cover basic theory of GNSS for a senior-level class in geomatics, electrical engineering, systems engineering, and computer science. Subjects covered in detail include basic GNSS satellite signal structures, practical receiver antenna designs, receiver implementation structures, error sources, signal processing methods for eliminating or reducing recognized error sources, and system augmentation methods for improving system integrity and security.

Chapter 10 covers the fundamental aspects of Kalman filtering essential for GNSS/INS integration: its mathematical foundations and basic implementation methods, and its application to sensor integration in general and to GNSS navigation in particular. It also covers how the implementation includes its own performance evaluation and how this can be used in the predictive design of sensor systems.

Chapter 11 covers the basic errors sources and models for inertial navigation, including the effects of sensor noise and errors due to drifting inertial sensor error characteristics, how the resulting navigation errors evolve over time, and the resulting models that enable INS integration with other sensor systems.

Chapter 12 covers the essential mathematical foundations for GNSS/INS integration, including a unified navigation model, its implementation in MATLAB, evaluations of the resulting unified system performance under simulated dynamic conditions, and demonstration of the navigation performance improvement attainable through integrated navigation.

Appendix A contains brief descriptions of the MATLAB software on the CD-ROM, including formulas implementing the models developed in the different chapters and used for demonstrating how they work. Appendix B contains background material on coordinate systems and transformations implemented in the software, including derivations of the rotational dynamics used in navigation error modeling and GNSS/INS integration.

For instructors that wish to cover the fundamental aspects of GNSS, Chapters 1, 2, and 4–9 are recommended. Instructors of courses covering the fundamental concepts of inertial navigation can cover Chapters 1, 3, 10, and 11. A more advanced course in GNSS and INS integration should include Chapter 12, as well as significant utilization of the software routines provided for computer-based GNSS/INS integration projects.

MOHINDER S. GREWAL, PH.D., P.E.California State University at Fullerton

ANGUS P. ANDREWS, PH.D.Rockwell Science Center (retired)Thousand Oaks, California

CHRIS G. BARTONE, PH.D., P.E.Ohio University, Athens, Ohio

ACKNOWLEDGMENTS

We acknowledge Professors John Angus of Claremont Graduate University, Jay A. Farrell of the University of California, Riverside, and Richard B. Langley of the University of New Brunswick for assistance and inspiration on the outline of this edition. We acknowledge the assistance of Mrs. Laura A. Cheung of the Raytheon Company for her expert assistance in reviewing Chapter 8 (“Differential GNSS”) and with the MATLAB® programs. Special thanks go to Dr. Larry Weill of California State University, Fullerton, for his contribution to Chapter 7 on multipath mitigation algorithms.

A. P. A. thanks Andrey Podkorytov at the Moscow Aviation Institute for corrections to the Schmidt–Kalman filter, Randall Corey from Northrop Grumman, and Michael Ash from C. S. Draper Laboratory for access to the developing Draft IEEE Standard for Inertial Sensor Technology; Dr. Michael Braasch at GPSoft, Inc. for providing evaluation copies of the GPSoft INS and GPS MATLAB® Toolboxes; Drs. Jeff Schmidt and Robert F. Nease, former Vice President of Engineering and Chief Scientist at Autonetics, respectively, for information on the early history of inertial navigation; Edward H. Martin for information on the very early history of GPS/INS integration; and Mrs Helen Boltinghouse for access to the personal memoirs of her late husband, Joseph C. Boltinghouse.

C. G. B. would like to thank Ohio University and many of its fine faculty, staff, and students with whom he has had the pleasure to interact in his research and teaching over the years. Such a rich environment has enabled him to develop a wide variety of classes and research efforts that these writings draw upon. Thanks also goes to Pat Fenton and Samantha Poon from NovAtel, Dave Brooks from Sensor Systems, James Horne from Roke, and Herbert Blaser from u-blox for providing antenna information.

ACRONYMS AND ABBREVIATIONS

3GPP           

3rd Generation Partnership Project

A/D

Analog-to-digital (conversion)

ADC

Analog-to-digital converter

ADR

Accumulated delta range

ADS

Automatic dependent surveillance

AGC

Automatic gain control

A-GPS

Assisted GPS

AHRS

Attitude and heading reference system

AIC

Akaike information-theoretic criterion

AIRS

Advanced Inertial Reference Sphere

ALF

Atmospheric loss factor

ALS

Autonomous landing systemalt

BOC

Alternate binary offset carrier

AODE

Age of data word, ephemeris

AOR-E

Atlantic Ocean Region East (WAAS)

AOR-W

Atlantic Ocean Region West (WAAS)

APL

Applied Physics Laboratory, Johns Hopkins University

AR

Autoregressive

AR

Axial ratio

ARMA

Autoregressive moving average

ARP

Antenna reference point

ARNS

Aeronautical radio navigation services

ASD

Amplitude spectral density

ASIC

Application-specific integrated circuit

ASQF

Application-Specific Qualification Facility (EGNOS)

A-S

Antispoofing

ATC

Air traffic control

BD

Bei Dou

BPF

Band pass filter

bps

bits per second

BOC

Binary offset carrier

BPSK

Binary phase-shift keying

BS

Base station

BW

Bandwidth

C

Civil

C/A

Coarse acquisition (channel or code)

C&V

Correction and verification (WAAS)

CDM

Code-division multiplexing

CDMA

Code-division multiple access

CEM

Computational electromagnetic model

CEP

Circular error probable, or circle of equal probability

CL

Code long

CM

Code moderate

CNAV

Civil navigation

CNMP

Code noise and multipath

CONUS

Conterminous United States, also Continental United States

CORS

Continuously operating reference station

COSPAS

Acronym from transliterated Russian title “Cosmicheskaya Sistyema Poiska Avariynich Sudov,” meaning “Space System for the Search of Vessels in Distress”

CBOC

Combined BOC

C/NAV

Commercial navigation

CP

Carrier phase

cps

Chips per second

CRC

Cyclic redundancy check

CRPA

Controlled reception pattern antenna

CS

Control segment

CSDL

Charles Stark Draper Laboratory

CWAAS

Canadian WAAS

DC

Direct current

DDA

Digital differential analyzer

DGNSS

Differential GNSS

DGPS

Differential GPS

DLL

Delay-lock loop

DME

Distance measurement equipment

DOD

Department of Defense (United States)

DOP

Dilution of precision

DU

Delay unit

E

Eccentric anomaly

ECEF

Earth-centered, earth-fixed (coordinates)

ECI

Earth-centered inertial (coordinates)

EGNOS

European (also Geostationary) Navigation Overlay System

EIRP

Effective isotropic radiated power

EMA

Electromagnetic accelerator

EMI

Electromagnetic interference

ENU

East–north–up (coordinates)

ESA

European Space Agency

ESG

Electrostatic gyroscope

ESGN

Electrically Supported Gyro Navigator

EU

European Union

EWAN

EGNOS Wide-Area (communication) Network (EGNOS)

FAA

Federal Aviation Administration (United States)

FDMA

Frequency division multiple access

FEC

Forward error correction

FIR

Finite impulse response

FLL

Frequency-lock loop

FM

Frequency modulation

FOG

Fiber-optic gyroscope

FPE

Final prediction error (Akaike’s)

FSLF

Free-space loss factor

F/NAV

Free navigation

ft

Feet

GAGAN

GPS & GEO Augmented Navigation (India)

GBAS

Ground-based augmentation system

GCCS

GEO Communication and Control Segment

GDOP

Geometric dilution of precision

GEO

Geostationary earth orbit

GES

GPS Earth Station COMSAT

GIC

GNSS Integrity Channel

GIOVE

Galileo In-Orbit Validation Element

GIPSY

GPS Infrared Positioning System

GIS

Geographic Information System(s)

GIVE

Grid ionosphere vertical error

GLONASS

Global Orbiting Navigation Satellite System

GNSS

Global navigation satellite system

GOA

GIPSY/OASIS analysis

GPS

Global Positioning System

GUS

GEO uplink subsystem

GUST

GEO uplink subsystem type 1

h

hour

HDOP

Horizontal dilution of precision

HEO

Highly-inclined elliptical orbit

HMI

Hazardously misleading information

HOW

Handover word

HPNS

High precision navigation signal (i.e., for GLONASS)

HRG

Hemispheric resonator gyroscope

I

In-phase

ICAO

International Civil Aviation Organization

ICC

Ionospheric correction computation

ICD

Interface control document

IDV

Independent Data Verification (of WAAS)

IF

Intermediate frequency

IFOG

Interferometric fiber-optic gyroscope

IGO

Inclined geosynchronous orbit

IGP

Ionospheric grid point (for WAAS)

IGS

International GNSS Service

ILS

Instrument landing system

IMU

Inertial measurement unit

Inmarsat

International Mobile (originally “Maritime”) Satellite Organization

I/NAV

Integrity navigation

INS

Inertial navigation system

IOD

Issue of data

IODC

Issue of data clock

IODE

Issue of data ephemeris

IONO

Ionosphere, ionospheric

IOT

In-orbit test

IRU

Inertial reference unit

IS

Interface specification

ISA

Inertial sensor assembly

ITRF

International Terrestrial Reference Frame

ITU

International Telecommunications Union

JPALS

Joint precision approach and landing system

JTIDS

Joint Tactical Information Distribution System

km

Kilometer

KPA

Klystron Power Amplifier

LAAS

Local-Area Augmentation System

LADGPS

Local-area differential GPS

LAMBDA

Least-squares ambiguity decorrelation adjustment

LD

Location determination

LEM

Lunar Excursion Module

LHCP

Left-hand circularly polarized

LINCS

Local Information Network Communication System

LIS

Land Information Systems

LNA

Low-noise amplifier

LORAN

Long-range navigation

LOS

Line of sight

LP

Linear polarization

LPV

Lateral positioning with vertical guidance

LSB

Least significant bit

LTP

Local tangent plane

M

Mean anomaly

m

Meter

M

Military

MBOC

Modified BOC

MCC

Mission/Master Control Center (EGNOS)

Mcps

million chips per second

MEDLL

Multipath-estimating delay-lock loop

MEMS

Microelectromechanical system(s)

MEO

Medium earth orbit

MS

Mobile station (i.e., cell phone)

ML

Maximum likelihood

MLE

Maximum-likelihood estimation (or estimator)

MMIA

Mueller Mechanical Integrating Accelerometer

MMSE

Minimum mean-squared error (estimator)

MMT

Multipath mitigation technology

MOPS

Minimum Operational Performance Standards

MSAS

MTSAT Satellite-based Augmentation System (Japan)

MSB

Most significant bit

MTSAT

Multifunctional Transport Satellite (Japan)

MVDR

Minimum variance distortionless response

MVUE

Minimum-variance unbiased estimator

MWG

Momentum wheel gyroscope

NAS

National Airspace System

NAVSTAR

Navigation system with time and ranging

NCO

Numerically controlled oscillator

NED

North–east–down (coordinates)

NF

Noise figure

NGS

National Geodetic Survey (United States)

NLES

Navigation Land Earth Station(s) (EGNOS)

NOAA

National Oceanic and Atmospheric Administration

NPA

Nonprecision approach

NSRS

National Spatial Reference System

NSTB

National Satellite Test Bed

OASIS

Orbit analysis simulation software

OBAD

Old but active data

OD

Orbit determination

OPUS

Online Positioning User Service (of NGS)

OS

Open Service (of Galileo)

PA

Precision approach

PACF

Performance Assessment and Checkout Facility (EGNOS)

P-code

Precision code

pdf

portable document format

PDI

Predetection integration interval

PDOP

Position dilution of precision

PI

Proportional and integral (controller)

PID

Process input data (of WAAS); proportional, integral, and differential (control)

PIGA

Pendulous integrating gyroscopic accelerometer

PL

Pseudolite

PLL

Phase-lock loop

PLRS

Position Location and Reporting System (U.S. Army)

PN

Pseudorandom noise

POR

Pacific Ocean Region

PPP

Precise point positioning

PPS

Precise Positioning Service

pps

Pulse per second

PR

Pseudorange

PRC

People’s Republic of China

PRN

Pseudorandom noise or pseudorandom number (=SVN for GPS)

PRS

Public Regulated service (of Galileo)

PSD

Power spectral density

Q

Quadrature

QPSK

Quadrature phase shift keying

QZS

Quasi-Zenith Satellite

QZSS

Quasi-Zenith Satellite System

RAAN

right ascension of ascending node

RAG

Receiver antenna gain (relative to isotropic)

RAIM

Receiver autonomous integrity monitoring

RF

Radio frequency

RHCP

Right-hand circularly polarized

RIMS

Ranging and Integrity Monitoring Station(s) (EGNOS)

RINEX

Receiver independent exchange format (for GPS data)

RL

Return loss

RLG

Ring laser gyroscope

RMA

Reliability, maintainability, availability

RMS

Root mean square; reference monitoring station

RNSS

Radio navigation satellite service

RPY

Roll–pitch–yaw (coordinates)

RTCA

Radio Technical Commission for Aeronautics

RTCM

Radio Technical Commission for Maritime Service

RTOS

Real-time operating system

RVCG

Rotational vibratory coriolis gyroscope

s

second

SA

Selective availability (also abbreviated “S/A”)

SAIF

Submeter accuracy with integrity function (in QZSS)

SAP

Space adaptive processing

SAR

Synthetic Aperture Radar or Search and Rescue (Galileo service)

SARP

Standards and Recommended Practices (Japan)

SARSAT

Search and rescue satellite—aided tracking

SAW

Surface acoustic wave

SBAS

Space-based augmentation system

SBIRLEO

Space-based infrared low earth orbit

SCOUT

Scripps coordinate update tool

SCP

Satellite Correction Processing (of WAAS)

SDR

Software-defined radio

SF

Scale factor

SFAP

Space-frequency adaptive processing

SFIR

Specific force information receiver

SI

Système International

SIS

Signal in space

SM

Solar magnetic

SNAS

Satellite Navigation Augmentation System (China)

SNR

Signal-to-noise ratio

SOL

Safety of Life Service (of Galileo)

SPNS

Standard precision navigation signal (i.e., for GLONASS)

SPS

Standard Positioning Service

sps

symbols per second

SSBN

Ship Submersible Ballistic Nuclear (US)

STAP

Space–time adaptive processing

STF

Signal Task Force (of Galileo)

STM

State transition matrix

SV

Space vehicle

SVN

Space vehicle number (=PRN number for GPS)

SWR

Standing wave ratio

TCS

Terrestrial communications subsystem (for WAAS)

TCXO

Temperature-compensated Xtat (crystal) oscillator

TDOA

Time difference of arrival

TDOP

Time dilution of precision

TEC

Total electron content

TECU

Total electron content units

TCN

Terrestrial Communication Network

TLM

Telemetry word

TLT

Test Loop Translator

TMBOC

Time-multiplexed BOC

TOA

Time of arrival

TOW

Time of week

TTA

Time to alarm

TTFF

Time to first fix

UDRE

User differential range error

UERE

User-equivalent range error

URE

User range error

USAF

United States Air Force

USN

United States Navy

UTC

Universal Time, Coordinated (or Coordinated Universal Time)

UTM

Universal Transverse Mercator

VAL

Vertical alert limit

VCG

Vibratory Coriolis gyroscope

VDOP

Vertical dilution of precision

VHF

Very high frequency (30–300 MHz)

VOR

VHF omnirange (radionavigation aid)

VRW

Velocity random walk

WAAS

Wide-Area Augmentation System (United States)

WADGPS

Wide-area differential GPS

WGS

World Geodetic System

WMP

WAAS Message Processor

WMS

Wide-area master station

WN

Week number

WNT

WAAS network time

WRE

Wide-area reference equipment

WRS

Wide-area reference station

ZLG

Zero-Lock Gyroscope (“Zero Lock Gyro” and “ZLG” are trademarks of Northrop Grumman Corp.)

1INTRODUCTION

A book on navigation? Fine reading for a child of six!1

1.1 NAVIGATION

During the European Age of Discovery, in the fifteenth to seventeenth centuries, the word navigation was synthesized from the Latin noun navis (ship) and the Latin verb stem agare (to do, drive, or lead) to designate the operation of a ship on a voyage from A to B—or the art thereof.

In this context, the word art is used in the sense of a skill, craft, method, or practice. The Greek word for it is τεχνυ, with which the Greek suffix -λγια (the study thereof) gives us the word technology.

1.1.1 Navigation-Related Technologies

In current engineering usage, the art of getting from A to B is commonly divided into three interrelated technologies:

Navigation

refers to the art of determining the current location of an object—usually a vehicle of some sort, which could be in space, in the air, on land, on or under the surface of a body of water, or underground. It could also be a comet, a projectile, a drill bit, or anything else we would like to locate and track. In modern usage,

A

and

B

may refer to the object’s current and intended dynamic

state

, which can also include its velocity, attitude, or attitude rate relative to other objects. The practical implementation of navigation generally requires observations, measurements, or sensors to measure relevant variables, and methods of estimating the state of the object from the measured values.

Guidance

refers to the art of determining a suitable trajectory for getting the object to a desired

state

, which may include position, velocity, attitude, or attitude rate. What would be considered a “suitable” trajectory may involve such factors as cost, consumables and/or time required, risks involved, or constraints imposed by existing transportation corridors and geopolitical boundaries.

Control

refers to the art of determining what actions (e.g., applied forces or torques) may be required for getting the object to follow the desired trajectory.

These distinctions can become blurred—especially in applications when they share hardware and software. This has happened in missile guidance [2], where the focus is on getting to B, which may be implemented without requiring the intermediate locations. The distinctions are clearer in what is called “Global Positioning System (GPS) navigation” for highway vehicles, where

Navigation

is implemented by the GPS receiver, which gives the user an estimate of the current location (

A

) of the vehicle.

Guidance

is implemented as

route planning

, which finds a route (trajectory) from

A

to the intended destination

B

, using the connecting road system and applying user-specified measures of route suitability (e.g., travel distance or total time).

Control

is implemented as a sequence of requested driver actions to follow the planned route.

1.1.2 Navigation Modes

From time immemorial, we have had to solve the problem of getting from A to B, and many solution methods have evolved. Solutions are commonly grouped into five basic navigation modes, listed here in their approximate chronological order of discovery:

Pilotage

essentially relies on recognizing your surroundings to know where you are (

A

) and how you are oriented relative to where you want to be (

B

). It is older than human kind.

Celestial navigation

uses relevant angles between local vertical and celestial objects (e.g., the sun, planets, moons, stars) with known directions to estimate orientation, and possibly location on the surface of the earth. Some birds have been using celestial navigation in some form for millions of years. Because the earth and these celestial objects are moving with respect to one another, accurate celestial navigation requires some method for estimating time. By the early eighteenth century, it was recognized that estimating longitude with comparable accuracy to that of latitude (around half a degree at that time) would require clocks accurate to a few minutes over long sea voyages. The requisite clock technology was not developed until the middle of the eighteenth century, by John Harrison (1693–1776). The development of atomic clocks in the twentieth century would also play a major role in the development of satellite-based navigation.

Dead reckoning

relies on knowing where you started from, plus some form of heading information and some estimate of speed and elapsed time to determine the distance traveled. Heading may be determined from celestial observations or by using a magnetic compass. Dead reckoning is generally implemented by plotting lines connecting successive locations on a chart, a practice at least as old as the works of Claudius Ptolemy (∼85–168 AD).

Radio navigation

relies on radio-frequency sources with known locations, suitable receiver technologies, signal structure at the transmitter, and signal availability at the receiver. Radio navigation technology using land-fixed transmitters has been evolving for nearly a century. Radio navigation technologies using satellites began soon after the first artificial satellite was launched by the former Soviet Union in 1957, but the first global positioning system (GPS) was not declared operational until 1993. Early radio navigation systems relied on electronics technologies, and global navigational satellite system (GNSS) also relies on computer technology and highly accurate clocks. Due to the extremely high speed of electromagnetic propagation and the relative speeds of satellites in orbit, GNSS navigation also requires very precise and accurate timing. It could be considered to be a celestial navigation system using artificial satellites as the celestial objects, with observations using radio navigation aids and high-accuracy clocks.

Inertial navigation

is much like an automated form of dead reckoning. It relies on knowing your initial position, velocity, and attitude, and thereafter measuring and integrating your accelerations and attitude rates to maintain an estimate of velocity, position, and attitude. Because it is self-contained and does not rely on external sources, it has the potential for secure and stealthy navigation in military applications. However, the sensor accuracy requirements for these applications can be extremely demanding [26]. Adequate sensor technologies were not developed until the middle of the twentieth century, and early systems tended to be rather expensive.

These modes of navigation can be used in combination, as well. The subject of this book is a combination of the last two modes of navigation: GNSS as a form of radio navigation, combined with inertial navigation. The key integration technology is Kalman filtering, which also played a major role in the development of both navigation modes.

The pace of technological innovation in navigation has been accelerating for decades. Over the last few decades, navigation accuracies improved dramatically and user costs have fallen by orders of magnitude. As a consequence, the number of marketable applications has been growing phenomenally. From the standpoint of navigation technology, we are living in interesting times.

1.2 GNSS OVERVIEW

There are currently four GNSSs operating or being developed. This section gives an overview; a more detailed discussion is given in Chapter 4.

1.2.1 GPS

The GPS is part of a satellite-based navigation system developed by the U.S. Department of Defense under its NAVSTAR satellite program [9, 11, 12, 14–18, 28–31].

1.2.1.1 GPS Orbits 

The fully operational GPS includes 31 or more active satellites approximately uniformly dispersed around six circular orbits with four or more satellites each. The orbits are inclined at an angle of 55° relative to the equator and are separated from each other by multiples of 60° right ascension. The orbits are nongeostationary and approximately circular, with radii of 26,560 km and orbital periods of one-half sidereal day (≈11.967 h). Theoretically, three or more GPS satellites will always be visible from most points on the earth’s surface, and four or more GPS satellites can be used to determine an observer’s position anywhere on the earth’s surface 24 h/day.

1.2.1.2 GPS Signals 

Each GPS satellite carries a cesium and/or rubidium atomic clock to provide timing information for the signals transmitted by the satellites. Internal clock correction is provided for each satellite clock. Each GPS satellite transmits two spread spectrum, L-band carrier signals on two of the legacy L-band frequencies—an L1 signal with carrier frequency f1 = 1575.42 MHz and an L2 signal with carrier frequency f2 = 1227.6 MHz. These two frequencies are integral multiples f1 = 1540f0 and f2 = 1200f0 of a base frequency f0 = 1.023 MHz. The L1 signal from each satellite uses binary phase-shift keying (BPSK), modulated by two pseudorandom noise (PRN) codes in phase quadrature, designated as the C/A-code and P-code. The L2 signal from each satellite is BPSK modulated by only the P(Y)-code. A brief description of the nature of these PRN codes follows, with greater detail given in Chapter 4.

Compensating for Ionosphere Propagation Delays 

This is one motivation for use of two different carrier signals, L1 and L2. Because delay through the ionosphere varies approximately as the inverse square of signal frequency f (delay ∝ f−2), the measurable differential delay between the two carrier frequencies can be used to compensate for the delay in each carrier (see Ref. 27 for details).

Code-Division Multiplexing 

Knowledge of the PRN codes allows users independent access to multiple GPS satellite signals on the same carrier frequency. The signal transmitted by a particular GPS signal can be selected by generating and matching, or correlating, the PRN code for that particular satellite. All PRN codes are known and are generated or stored in GPS satellite signal receivers. A first PRN code for each GPS satellite, sometimes referred to as a precision code or P-code, is a relatively long, fine-grained code having an associated clock or chip rate of 10f0 = 10.23 MHz. A second PRN code for each GPS satellite, sometimes referred to as a clear or coarse acquisition code or C/A-code, is intended to facilitate rapid satellite signal acquisition and handover to the P-code. It is a relatively short, coarser-grained code having an associated clock or chip rate f0 = 1.023 MHz. The C/A-code for any GPS satellite has a length of 1023 chips or time increments before it repeats. The full P-code has a length of 259 days, during which each satellite transmits a unique portion of the full P-code. The portion of P-code used for a given GPS satellite has a length of precisely 1 week (7.000 days) before this code portion repeats. Accepted methods for generating the C/A-code and P-code were established by the satellite developer (Satellite Systems Division of Rockwell International Corporation) in 1991 [10, 19].

Navigation Signal 

The GPS satellite bit stream includes navigational information on the ephemeris of the transmitting GPS satellite and an almanac for all GPS satellites, with parameters providing approximate corrections for ionospheric signal propagation delays suitable for single-frequency receivers and for an offset time between satellite clock time and true GPS time. The navigational information is transmitted at a rate of 50 baud. Further discussion of the GPS and techniques for obtaining position information from satellite signals can be found in [24].

1.2.1.3 Selective Availability (SA) 

SA is a combination of methods available to the U.S. Department of Defense to deliberately derate the accuracy of GPS for “nonauthorized” (i.e., non-U.S. military) users during periods of perceived threat. Measures may include pseudorandom time dithering and truncation of the transmitted ephemerides. The initial satellite configuration used SA with pseudorandom dithering of the onboard time reference only [19], but this was discontinued on May 1, 2000.

Precise Positioning Service (PPS) 

Formal, proprietary service PPS is the full-accuracy, single-receiver GPS positioning service provided to the United States and its allied military organizations and other selected agencies. This service includes access to the encrypted P-code and the removal of any SA effects.

Standard Positioning Service (SPS) without SA 

SPS provides GPS single-receiver (stand-alone) positioning service to any user on a continuous, worldwide basis. SPS is intended to provide access only to the C/A-code and the L1 carrier.

1.2.1.4 Modernization of GPS 

GPS IIF, GPS IIR-M, and GPS III are being designed under various contracts (Raytheon, Lockheed Martin). These will have a new L2 civil signal and new L5 signal modulated by a new code structure. These frequencies will improve the ambiguity resolution, ionospheric calculation, and C/A-code positioning accuracy.

1.2.2 Global Orbiting Navigation Satellite System (GLONASS)

A second system for global positioning is the GLONASS, placed in orbit by the former Soviet Union, and now maintained by the Russian Republic [21, 22].

1.2.2.1 GLONASS Orbits 

GLONASS has 24 satellites, distributed approximately uniformly in three orbital planes (as opposed to six for GPS) of eight satellites each (four for GPS). Each orbital plane has a nominal inclination of 64.8° relative to the equator, and the three orbital planes are separated from each other by multiples of 120° right ascension. GLONASS orbits have smaller radii than GPS orbits, about 25,510 km, and a satellite period of revolution of approximately 8/17 of a sidereal day.

1.2.2.2 GLONASS Signals 

The GLONASS system uses frequency-division multiplexing of independent satellite signals. Its two carrier signals corresponding to L1 and L2 have frequencies f1 = (1.602 + 9k/16) GHz and f2 = (1.246 + 7k/16) GHz, where k = −7, −6, … 5, 6 is the satellite number. These frequencies lie in two bands at 1.598–1.605 GHz (L1) and 1.242–1.248 GHz (L2). The L1 code is modulated by a C/A-code (chip rate = 0.511 MHz) and by a P-code (chip rate = 5.11 MHz). The L2 code is presently modulated only by the P-code. The GLONASS satellites also transmit navigational data at a rate of 50 baud. Because the satellite frequencies are distinguishable from each other, the P-code and the C/A-code are the same for each satellite. The methods for receiving and analyzing GLONASS signals are similar to the methods used for GPS signals. Further details can be found in the patent by Janky [19]. GLONASS does not use any form of SA.

1.2.2.3 Next Generation GLONASS 

The satellite for the next generation of GLONASS-K was launched on February 26, 2011 and continues to undergo flight tests. This satellite is transmitting a test CDMA signal at a frequency of 1202 MHz.

1.2.3 Galileo

The Galileo system is the third satellite-based navigation system currently under development. Its frequency structure and signal design is being developed by the European Commission’s (EC’s) Galileo Signal Task Force (STF), which was established by the EC in March 2001. The STF consists of experts nominated by the European Union (EU) member states, official representatives of the national frequency authorities, and experts from the European Space Agency (ESA).

1.2.3.1 Galileo Navigation Services 

The EU intends the Galileo system to provide the following four navigation services plus one search and rescue (SAR) service.

Open Service (OS) 

The OS provides signals for positioning and timing, free of direct user charge, and is accessible to any user equipped with a suitable receiver, with no authorization required. In this respect, it is similar to the current GPS L1 C/A-code signal. However, the OS is expected to be of higher quality, consisting of six different navigation signals on three carrier frequencies. OS performance is expected to be at least equal to that of the modernized Block IIR-M GPS satellites, which began launching in 2005, and the future GPS III system architecture currently being developed. OS applications will include the use of a combination of Galileo and GPS signals, thereby improving performance in severe environments such as urban canyons and heavy vegetation.

Safety of Life Service (SOL) 

The SOL service is intended to increase public safety by providing certified positioning performance, including the use of certified navigation receivers. Typical users of SOL will be airlines and transoceanic maritime companies. The European (also Geostationary) Navigation Overlay System (EGNOS) regional European enhancement of the GPS system will be optimally integrated with the Galileo SOL service to have independent and complementary integrity information (with no common mode of failure) on the GPS and GLONASS constellations. To benefit from the required level of protection, SOL operates in the L1 and E5 frequency bands reserved for the Aeronautical Radionavigation Services.

Commercial Service (CS) 

The CS service is intended for applications requiring performance higher than that offered by the OS. Users of this service pay a fee for the added value. CS is implemented by adding two additional signals to the OS signal suite. The additional signals are protected by commercial encryption and access protection keys are used in the receiver to decrypt the signals. Typical value-added services include service guarantees, precise timing, ionospheric delay models, local differential correction signals for very high-accuracy positioning applications, and other specialized requirements. These services will be developed by service providers, which will buy the right to use the two commercial signals from the Galileo operator.

Public Regulated Service (PRS) 

The PRS is an access-controlled service for government-authorized applications. It is expected to be used by groups such as police, coast guards, and customs. The signals will be encrypted, and access by region or user group will follow the security policy rules applicable in Europe. The PRS will be operational at all times and in all circumstances, including periods of crisis. A major feature of PRS is the robustness of its signal, which protects it against jamming and spoofing.

SAR 

The SAR service is Europe’s contribution to the international cooperative effort on humanitarian SAR. It will feature near real-time reception of distress messages from anywhere on Earth, precise location of alerts (within a few meters), multiple satellite detection to overcome terrain blockage, and augmentation by the four low earth orbit (LEO) satellites and the three geostationary satellites in the current Cosmitscheskaja Sistema Poiska Awarinitsch-Search and Rescue Satellite (COSPAS-SARSAT) system.

1.2.3.2 Galileo Signal Characteristics 

Galileo will provide 10 right-hand circularly polarized navigation signals in three frequency bands. The various signals fall into four categories: F/Nav, I/Nav, C/Nav, and G/Nav. The F/Nav and I/Nav signals are used by the OS, CS, and SOL services. The I/Nav signals contain integrity information, while the F/Nav signals do not. The C/Nav signals are used by the CS, and the G/Nav signals are used by the PRS.

E5a–E5b Band 

This band, which spans the frequency range from 1164 to 1214 MHz, contains two signals, denoted E5a and E5b