ION GNSS+ Tutorials

ION GNSS+ pre-conference tutorials have been organized to provide in-depth learning of specific GNSS-related disciplines and will be taught in a classroom setting. Course notes will be provided to registered attendees via the meeting website and a link provided for advance download.

In-Person Attendance: For those attending the conference in-person, AC power will not be made available for individual laptop computers; please come prepared with adequate battery power if required. It is recommended that attendees dress in layers to accommodate varying temperatures in the classroom.

Virtual Learning: The course will be recorded. Registered students may view the recorded course one time within 30 days. Those viewing the recording will not have real-time access to instructor(s) for live chat or question and answer. Note that the virtual learning option allows you to register for tutorials scheduled at the same time.

Tutorial Costs and Registration:
$450 per course if registered and paid by August 16
$500 per course if payment is received after August 16

Register using the ION GNSS+ Registration Form (see the registration page for additional information and policies). ION reserves the right to cancel a tutorial. If cancelled, the full cost of the course will be refunded via the original payment method.

Tuesday, September 17: 8:30 a.m. - 12:00 p.m.
Multi-constellation GNSS Signals and Systems
Dr. Chris G. Bartone, P.E.
GNSS Integrity
Dr. Mathieu Joerger
PNT for sUAVs
Dr. Rob Leishman
Kalman Filter
Dr. Kirsten Strandjord
Tuesday, September 17: 1:30 p.m. - 5:00 p.m.
Introduction to Software Defined GNSS Receivers and Signal Processing
Dr. Sanjeev Gunawardena
The Generation and Application of Precise Time
Dr. Michael J. Coleman
Space-Based Lunar PNT
Dr. Grace Gao
Factor Graphs
Dr. Clark Taylor / Dr. Ryan Watson
Ionospheric Effects, Monitoring, and Mitigation
Dr. Y. Jade Morton




Multi-constellation GNSS Signals and Systems

Date/Time: Tuesday, September 17, 8:30 a.m. - 12:00 p.m. MDT

Registration fee:
$450 if registered and paid by August 11
$500 if payment is received after August 11

Course Level: Beginner

This course emphasizes the fundamentals of multi-constellation GNSS. The course begins with an overview of GNSS followed by presentations on each of the GNSSs in operation and/or development today. The course will highlight common features of the various GNSSs and point out key differences between them.

Topics to be covered include:

  • GNSS segments; space, ground, user segments
  • GNSS link budget
  • Fundamental concept of GNSS position and time determination
  • GNSS coordinate frames and datums and time
  • GNSS signal structure formats: carrier, code, data
  • Direct sequence spread spectrum
  • GNSS antenna & receiver technologies – overview
  • GPS Legacy: C/A, P(Y) code and NAV formats
  • GPS Modernized: L2C, L5, L1C, CNAV and CNAV-2 formats
  • GLONASS
  • GLONASS SV versions
  • Legacy C/A, P codes and FDMA signals
  • Modernized CDMA codes and frequencies
  • Galileo, E1, E6/E6P, E5a, E5b, AltBOC, SAR Codes, frequencies and data formats
  • BeiDou, BDS I, BDS II, BDS III, B1, B2, B3 signals and formats
  • SBAS used throughout the globe
  • QZSS, L1, L2, L5, L6 signals, codes, and services
  • NAViC: L5, S band signals, message types
  • GNSS corrections for clock, code, atmospheric, transit time, etc.
  • GNSS user solutions

Dr. Chris G. Bartone, P.E. Dr. Chris G. Bartone, P.E., is a professor at Ohio University with over 35 years of professional experience and is an ION Fellow. He received his PhD EE from Ohio University, a MS EE from the Naval Postgraduate School, and BS EE from Penn State. Dr. Bartone has developed and teaches a number of GPS, radar, wave propagation and antenna classes. His research concentrates on all aspects of navigation.





GNSS Integrity

Date/Time: Tuesday, September 17, 8:30 a.m. - 12:00 p.m. MDT

Registration fee:
$450 if registered and paid by August 11
$500 if payment is received after August 11

Course Level: Intermediate

This course will describe (Part 1) fundamental concepts in GNSS integrity, (Part 2) successful implementations in aviation applications, and (Part 3) major challenges in future autonomous navigation for air, ground, and sea transportation. The course will emphasize Receiver Autonomous Integrity Monitoring (RAIM); it will include a handout on RAIM theory and a set of problems with solutions and MATLAB codes.

In Part 1, we will define navigation safety metrics and requirements including integrity and continuity risks, alert limit, and time to alert. We will identify the three major over-bounding methods used to derive high-integrity signal-in-space error models. We will define GNSS faults including, for example, excessive satellite clock drifts. We will outline how integrity-monitoring responsibilities can be allocated between reference-station and user receivers and how prior probabilities of satellite faults are evaluated.

In Part 2, we will briefly describe the major implementations used in aviation applications: the Ground-Based Augmentation Systems (GBAS), the Space-Based Augmentation Systems (SBAS) and the Aircraft-Based Augmentation System (ABAS). We will focus on RAIM and Advanced RAIM; we will use graphical tools of failure mode curves and parity space representations to identify differences between solution separation and chi-squared approaches. We will show recent developments in ARAIM intended to optimize ARAIM integrity and continuity monitoring performance while limiting computational load.

In Part 3, we will review recent efforts in standard developments and performance evaluations to achieve safe navigation in aviation, maritime, railway, and automotive applications. We will discuss recent research on robust modeling of measurement error time correlation that enables high-integrity Kalman filtering of combined GNSS and inertial data. We will identify major challenges in implementing precise point positioning (PPP) and real time kinematic (RTK) to simultaneously achieve high accuracy and high integrity.

Dr. Mathieu Joerger Dr. Mathieu Joerger is an assistant professor at Virginia Tech, recipient of ION’s Parkinson Award (2009), Early Achievement Award (2014), Burka Award and Thurlow Award (2023). He is the senior editor on Navigation for IEEE TAES and a member of the EU/US ARAIM Working-Group-C for the FAA. He received his PhD from Illinois Institute of Technology.





PNT for sUAVs

Date/Time: Tuesday, September 17, 8:30 a.m. - 12:00 p.m. MDT

Registration fee:
$450 if registered and paid by August 11
$500 if payment is received after August 11

Course Level: Beginner to Intermediate

Small Unmanned Aerial Vehicles (sUAVs) are becoming increasingly ubiquitous. While their utilization may not have quite hit projections offered by venture capitalists over the last decade, these vehicles have found utility and have been incorporated into products in a wide variety of ways, for example: remote-control flying, photography and videography, infrastructure/agriculture/construction site inspection, product/medical delivery, racing, mapping, intelligence, surveillance and reconnaissance (ISR), and defense.

sUAVs have been and will continue to be fantastic platforms for enabling research in GNC, PNT, and many other disciplines. A key reason is that sUAVs offer the unique constraint of coupling low size, weight, and power (SWAP) with a critical need for urgency and timeliness of PNT and control information. This class will review the consequences of this unique constraint and the influences on both sensors and algorithms.

This course is a hands-on introduction and review of PNT for sUAVs and will provide in-depth information on current sensors, autopilots, software architectures, and algorithms for PNT. One key algorithm for navigation for sUAVs has been visual-inertial odometry (VIO). This modality, often enabled by machine learning approaches, has been optimized to strike the unique balanced required for the SWAP-timeliness constraint mentioned. This class will provide a hands-on dive into VIO methods and provide python examples to promote further understanding.

This course is applicable for those wanting to utilize UAVs for research, as well as those desiring to better understand the current state of the art in PNT for sUAVs. Pre-requisites and equipment: a basic understanding of PNT topics, including estimation and sensor fusion and object-oriented programming and Python programming language familiarity for the VIO software projects. Attendees will need their own charged laptops if they want to work on the projects in-class. Relevant course materials/notes and software examples are provided to registered attendees in advance.

Dr. Rob Leishman Dr. Rob Leishman is currently the PNT Area Lead with IS4S and the Mission Capable Navigation Lead for the Resilient Embedded GPS and INS (R-EGI) program. Formerly, he was director of the Autonomy and Navigation Technology (ANT) Center at the Air Force Institute of Technology. There Dr. Leishman led a team of researchers and students in developing cutting-edge, defense-focused autonomy and navigation technologies, primarily for sUAVs.





Kalman Filter

Date/Time: Tuesday, September 17, 8:30 a.m. - 12:00 p.m. MDT

Registration fee:
$450 if registered and paid by August 11
$500 if payment is received after August 11

Course Level: Beginner to Intermediate

The Kalman filter is a powerful recursive estimation algorithm and it lies at the intersection of probability theory and linear algebra. Its effectiveness stems from its ability to optimally estimate the state of a dynamic system in the presence of uncertain, noisy measurements. Probability theory provides the framework to model this uncertainty, as the filter relies on probabilistic models for both the system dynamics and measurement processes. Linear algebra serves as the mathematical backbone for implementing the filter's computational efficiency. Understanding both probability and linear algebra is crucial for comprehending underlying principles and effectively applying the filter in various real-world scenarios.

Concepts to be covered include matrix operations, state-space representation of dynamical systems, recursive linear least squares, and pure prediction. Probability concepts will be explored to grasp the stochastic nature of measurement and process noise, integral in the Kalman filter framework. Key topics in probability include conditional probability, probability distributions such as Gaussian distributions, expected values, and covariance matrices, crucial for modeling uncertainty in navigation systems. Finally, we will conclude by discussing strategies for tuning and evaluating the performance of different filters, ensuring optimal functionality in real-world applications.

Dr. Kirsten Strandjord Dr. Kirsten Strandjord is an assistant professor at the University of Minnesota in Aerospace Engineering. She received her PhD in Aerospace Engineering Sciences from the University of Colorado Boulder, MS in Aeronautical and Astronautical Engineering from Purdue University, and BA in Mathematics, Physics, and Computer Science from Luther College.





Introduction to Software Defined GNSS Receivers and Signal Processing

Date/Time: Tuesday, September 17, 1:30 p.m. - 5:00 p.m. MDT

Registration fee:
$450 if registered and paid by August 11
$500 if payment is received after August 11

Course Level: Beginner to Intermediate

This course aims to provide attendees with a solid understanding of the fundamentals of satellite timing and navigation (satnav) software receivers and associated signal processing. The course is divided into multiple modules, each comprised of a short lecture followed by a software demo that reinforces the concepts and techniques covered. By the end of this course, attendees will have an easy-to-use satnav software receiver running on their laptop that takes multiband live-sky sampled data files, acquires and tracks visible open satnav signals, and outputs signal observables. This receiver is fully configured using JavaScript Object Notation (JSON) files such that modification of the source code is not required. It may be further extended to support numerous advanced research applications.

Topics covered:

  • Overview of satnav bands, signal structures, link budget, and receiver architecture
  • FFT-based signal acquisition and adapting circular correlation to long spreading codes
  • Software-based methods for correlation acceleration: bit-wise, multi-threading, SIMD
  • Carrier tracking loops: FLL, PLL and FLL-aided-PLL
  • Code tracking loops: DLL, non-coherent vs. coherent tracking, correlator spacing, and carrier aiding
  • Tracking of open satnav signals: GPS, GLONASS, Galileo, BeiDou, QZSS, NavIC, and SBAS
  • Internal decision making and control procedures based on signal environment and application
  • Measurement computation (pseudorange, accumulated doppler range/carrierphase)
  • Direct instantiation for multi-frequency tracking (e.g. Galileo E1 to E5a/b)
  • Inter-frequency aiding and duty cycling techniques for low-power applications (e.g. L1/L5 smartphones)

Pre-requisites and equipment: Basic understanding of digital signal processing, object-oriented programming concepts and the Python programming language are helpful but not required to attend this course. Numerous fully-functional demo projects will be provided. If intending to run the demos during the course, attendees must supply their own laptop computers with adequate battery power. The instructor will provide relevant information to registered attendees in advance of the course.

Dr. Sanjeev Gunawardena Dr. Sanjeev Gunawardena is a research associate professor with the Autonomy & Navigation Technology (ANT) Center at the Air Force Institute of Technology (AFIT). He has 25 years of experience in RF, digital and FPGA-based system design. His expertise includes satnav receiver design, advanced satnav signal processing and implementation. Dr. Gunawardena received a BS in engineering physics and a BSEE, MSEE and PhD EE from Ohio University.





The Generation and Application of Precise Time

Date/Time: Tuesday, September 17, 1:30 p.m. - 5:00 p.m. MDT

Registration fee:
$450 if registered and paid by August 11
$500 if payment is received after August 11

Course Level: Beginner to Intermediate

Time and frequency are fundamental concepts in the design of many technologies, especially the Global Navigation Satellite Systems (GNSS) on which we are quite reliant for navigation. Even alternative sources of navigation and legacy approaches to geo-positioning rely upon precise clocks. Industries from utilities to financial markets are also dependent on time synchronization with ever increasing needs for precision. For these reasons, understanding the base measurements and realizations of time can be useful for a growing number of research and development areas. This tutorial aims to introduce the foundational elements of time, from its definition to its dissemination into the user segment.

The main topics this course will cover are: the definition and realization of the SI second; generic design of various atomic frequency standards; statistics and metrics quantifying clock performance; the generation of international timescales and local clock ensembles; the comparison of remote timescales or clocks; and applications of these elements to various industries as well as navigation accuracy. Since foundations of precise time are the main thrust, there will be heavier emphasis on the former topics listed above. Important time comparison techniques including two way time transfer will be covered. The material will also highlight recent findings from the timing community on important topics regarding time and frequency and their dissemination by GNSS.

This course is geared towards scientists without significant experience in time metrology or clocks who desire an introduction to these topics. It will be assumed that attendees have a high-level understanding of the role of GNSS clocks, but nothing about the specifics topics mentioned above.

Dr. Michael J. Coleman Dr. Michael J. Coleman is a research mathematician in the Naval Center for Space Technology at the US Naval Research Laboratory in Washington, DC. He is also head of the Systems Analysis Section within the Space PNT Branch. His main work at NRL has been development of the next generation GPS timescale and alternative or experimental precise time dissemination systems. Dr. Coleman chairs the Clock Products Committee of the International GNSS Service and is a delegate to the BIPM’s Consultative Committee on Time and Frequency.





Space-Based Lunar PNT

Date/Time: Tuesday, September 17, 1:30 p.m. - 5:00 p.m. MDT

Registration fee:
$450 if registered and paid by August 11
$500 if payment is received after August 11

Course Level: Beginner

We are entering a new era of Moon exploration. There are more than forty missions planned within the next decade by ten space agencies, not even counting the efforts of private sector companies like SpaceX and Blue Origin. After more than fifty years since the Apollo program, NASA's Artemis mission will land humans on the Moon including the first woman and first person of color. Exploring the Moon also serves as a crucial stepping-stone for the success of future deep space missions. With the increase in human and robotic exploration, we must provide position, navigation, and timing (PNT) services anywhere on the Moon. In this tutorial, we will cover the following topics.

  • An introduction to currently planned missions for lunar exploration
  • Main lunar navigation services and Key Performance Indicators (KPIs)
  • Overview of candidate orbits for lunar navigation
  • End-to-end navigation architecture
  • Candidate orbit determination and time synchronization (ODTS) baseline solution for lunar navigation
  • Lunar reference frames
  • Frequencies selected for lunar navigational signals
  • Lunar PNT engine for different user missions, such as descent and landing and rover surface PNT

Dr. Grace Gao Dr. Grace Gao is faculty in the Department of Aeronautics and Astronautics at Stanford University. She leads the Navigation and Autonomous Vehicles Laboratory (NAV Lab). Her research is on robust and secure position, navigation and time (PNT) with applications to manned and unmanned aerial vehicles, autonomous driving cars, as well as space robotics.





Factor Graphs

Date/Time: Tuesday, September 17, 1:30 p.m. - 5:00 p.m. MDT

Registration fee:
$450 if registered and paid by August 11
$500 if payment is received after August 11

Course Level: Intermediate (attendees should have an introductory knowledge of filtering)

While the Kalman Filter (KF) family (linear KF, EKF, UKF, etc.) has been the workhorse of navigation systems for several decades, the factor graph is a generalization of the Kalman Filter that offers improved performance for non-linear systems and is more easily applied to complex systems. The goal of this tutorial is to take a practitioner who is familiar with the Extended Kalman filter and introduce them to factor graphs. By the end of the tutorial, the attendants should be able to create a simple factor graph system and will have been exposed to some of the more advanced concepts that make factor graphs an exceptional choice for navigation problems.

More specifically, this tutorial will introduce the factor graph representation of dynamic systems and how this representation is equivalent to a weighted least squares problem that can be solved with sparse matrix computational tools. We will demonstrate the (surprisingly low) computational costs of factor graphs and methods used to keep those costs low. We will also introduce popular software packages that can be used to solve factor graph problems, including GTSAM. Complex estimation problems that can be difficult to handle with other estimation frameworks will be introduced in the factor graph framework and examples solutions to these problems will be demonstrated.

Dr. Clark Taylor Dr. Clark Taylor is the Autonomy and Navigation Technology (ANT) center director at the Air Force Institute of Technology. He received his PhD from University of California, San Diego in 2004 and previously worked as a senior research engineer with the Air Force Research Laboratory and an assistant professor in electrical engineering at Brigham Young University.


Dr. Ryan Watson Dr. Ryan Watson currently works at Xona Space Systems enabling integrity for their LEO satellite navigation constellation. He previously worked at the NASA Jet Propulsion Laboratory and the Johns Hopkins University Applied Physics Laboratory on problems related to state estimation/data fusion for robotic and space missions. He holds a PhD from West Virginia University.





Ionospheric Effects, Monitoring, and Mitigation

Date/Time: Tuesday, September 17, 1:30 p.m. - 5:00 p.m. MDT

Registration fee:
$450 if registered and paid by August 11
$500 if payment is received after August 11

Course Level: Beginner to Intermediate

Ionospheric effects are major threats to the availability, continuity, and accuracy of GNSS solutions. Models, global networks of GNSS stations, and LEO satellite-based radio occultation constellations have been established to monitor and predict the ionospheric effects. This course will present an overview of the current state-of-art understanding of the various ionospheric effects on GNSS-based navigation systems and their mitigation techniques. The course consists of five parts. The first part is a review of the fundamental properties of the ionosphere that impact satellite navigation signals and PVT solutions. The second part discusses the ionospheric refractive effects, their contributions to the GNSS measurement model, Total Electron Content (TEC) estimation techniques and TEC products, higher order refraction errors, and refractive effect correction techniques. Part 3 covers ionospheric scintillation effect, with a focus on climatology and morphology of scintillation occurrences, and the impact of scintillation on RTK and PPP systems. Part 4 takes a deeper look into GNSS receiver signal processing algorithms designed to combat ionospheric scintillation for ground- and LEO satellite-based receivers. Part 5 will provide an update on the latest development in ionospheric effects monitoring and forecasting using machine learning algorithms, worldwide GNSS observations, as well as the ionospheric effects on signals transmitted from LEO satellites. We will finish the course with an outlook for outstanding challenges in the field.

Dr. Y. Jade Morton Dr. Jade Morton is Helen and Hubert Croft Professor in the Aerospace Engineering Sciences Department at the University of Colorado, Boulder. Her research interests lie at the intersection of satellite navigation technologies and remote sensing of Earth’s ionosphere, atmosphere, and surface. Dr. Morton was a president and Satellite Division Chair of ION, and a recipient of ION Thurlow, Burka, Kepler, IEEE PLANS Kershner, and AGU SPARC award. She is a Fellow of IEEE, ION, and RIN.