GPS & International Competitors

Course Length:



A thick swarm of radionavigation satellites – at least 128 of them! — will soon be orbiting our home planet. They will be owned and operated by six different sovereign nations hoping to capitalize on the technical and financial success of America’s highly successful GPS. In this comprehensive fourday short course Tom Logsdon will describe in detail how these various international navigation systems work and he will review the many practical benefits they are providing to civilian and military users scattered around the globe. He will also describe the salient features of each navigation system, describe its signal structure, and explain how you can use it most effectively in practical situations.

Course Outline:

  1. The GPS and Its Breakthrough Technologies. Carrier waves. Signal structure. Modulation techniques. Relativistic Time Dilations. Inverted navigation.
  2. Glonass: Russia’s Highly Capable Copy of the GPS. Performance capabilities. Orbital mechanics. Glonass subsystems. Russia’s SL-12 Proton booster. Dual-capability GPS/Glonass receivers.
  3. Minimizing Mutual Interference between International Constellations. Spread spectrum signals. Binary offset carrier modulation. Split spectrum approaches. Those magical Fourier Transforms. Finding the proper frequency ratios.
  4. Designing Effective Radionavigation Receivers. One-page block diagram. Passive and active antennas. Code tracking and carrier tracking loops. Commercial chipsets. Military receivers. Those remarkable breakthroughs in your cellphone. Spaceborne receivers.
  5. Military Applications. Tactical and strategic warfightiing capabilities. Autonomy and survivability enhancements. Smart bombs and artillery projectiles. Paveway weapon systems. Jamming. Spoofing. Cryptography. Spoofing countermeasures.
  6. The European Galileo and the Chinese BieDou. Consulting assignments in Strasbourg and Friedrichshaven . Early constellation designs. Galileo coming of age. The Chinese “Big Dipper”. Constellation iterations. Split spectrum signal structure. BeiDou’s special Navcom features.
  7. India’s IRNSS and Japan’s QZSS. The regional constellation being launched by India. Seven geosynchronous satellites dancing across the sky. Rubidium atomic clocks and corner cube reflectors. Figure-8 ground traces. Japan’s unique quasi-zenith constellation. Providing navigation, audio, video, and data services. Local-area coverage characteristics. Awesome summary charts.
  8. Popular Performance-Enhancement Techniques. Integrated GPS/Inertial navigation partnerships. Today’s ring laser gyros and fiber-optic gyros. MEMS technology. Differential navigation and pseudosatellites. Wide-area differential navigation. Carrier-aided solutions. 3D attitude-determination methodologies. Einstein’s theories of relativity and their impacts on spaceborne navigation systems.


  • The presenter was very energetic and truly passionate about the material.

  • Tom Logsdon is the best teacher I have ever had. His knowledge is excellent. He is a 10!

  • Mr. Logsdon did a bang-up job explaining and deriving the theories of special/general relativity - and how they are associated with today's navigation solutions.

  • I loved his one-page mathematical derivations and the important points they illustrate.


REGISTRATION:  There is no obligation or payment required to enter the Registration for an actively scheduled course.   We understand that you may need approvals but please register as early as possible or contact us so we know of your interest in this course offering.

SCHEDULING:  If this course is not on the current schedule of open enrollment courses and you are interested in attending this or another course as an open enrollment, please contact us at (410)956-8805 or Please indicate the course name, number of students who wish to participate. and a preferred time frame. ATI typically schedules open enrollment courses with a 3-5 month lead-time.   To express your interest in an open enrollment course not on our current schedule, please email us at

For on-site pricing, you can use the request an on-site quote form, call us at (410)956-8805, or email us at


  • Tom Logsdon has worked on radionavigation satellites and their constellations for more than 20 years. He helped design the Transit Navigation System and the GPS and he acted as a consultant to the European Galileo Spaceborne Navigation System. His key assignments have included constellation design, military and civilian applications, survivability enhancements and spacecraft autonomy studies.

    Over the past 30 years Logsdon has taught more than 300 short courses in 31 different countries scattered across six continents. He has also made two dozen television appearances, helped design an exhibit for the Smithsonian Institution, and written and published 1.8 million words, including 34 non-fiction books. These include Understanding the Navstar, Orbital Mechanics, and The Navstar Global Positioning System.

    Contact this instructor (please mention course name in the subject line)


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