Foreword

I built my first crystal radio kit when I was 9 years old. I became hooked on radio technology, even at that tender age, and later went on to build other radios as a teenager, including a shortwave receiver from a kit. I learned how radios worked by building them and tinkering with them. I learned much later on that the famous American physicist, Richard Feynman, also had an interest in radios when he was 11 or 12. He would buy broken radios at rummage sales and try to fix them. That’s the way he learned how they worked. As he says in the first chapter of his book Surely You’re Joking Mr. Feynman!–Adventures of a Curious Character, ‘The sets were simple, the circuits were not complicated . . . It wasn’t hard for me to fix a radio by understanding what was going on inside, noticing that something wasn’t working right, and fixing it.’ As we know, Feynman went on to unravel the nature of quantum mechanics amongst other accomplishments. And, all his life, he took great pleasure in finding things out.

My interest in radio and electronics together with a love of physics led me eventually into a teaching and research career in space geodesy and precision navigation. Over the years, I have been involved with a number of mostly radio-based space geodetic techniques. As a Ph.D. student, I worked with very long baseline interferometry (VLBI) and satellite Doppler (the US Navy Navigation Satellite System or Transit) and as a postdoctoral fellow at MIT, I worked with lunar laser ranging data and was introduced to one of the very first civil GPS receivers: the Macrometer™. Upon arriving at the University of New Brunswick’s then Department of Surveying Engineering in 1981, it was back to satellite Doppler. But within a year or two, GPS captured my attention and it has been virtually my sole interest ever since.