I’ve absorbed the basics of how GPS works in the decade since I joined the staff of GPS World magazine, when I barely gave the positioning system a thought. But in those first few months, this is the book I wish I’d had.
Terms I needed to learn back then included pseudorange (nothing to do with juicy fruit), geodesy (not an undiscovered work by Homer) and multipath (not a forking trail in a park).
All of these and more are described in the new book GPS for Everyone: You Are Here by Pratap Misra. Pratap is Professor of the Practice, Department of Mechanical Engineering at Tufts University, and he sent me his new book for review. As a non-engineer, I have found it a great resource — Pratap explains complex subjects in an entertaining, highly readable narrative, accompanied by photos, illustrations and even a few cartoons.
Even if I’m not looking for a little background, I find myself engaged in the story of GPS: its history, its uses today (location-based services, defense, UAVs), privacy concerns and more.
For instance, I hadn’t given much thought to how general relativity had to be taken into account in designing the clocks for GPS satellites. If the clocks hadn’t been designed with an offset, GPS would lose 38 milliseconds a day. So much for an accurate timing reference.
Aother interesting story was the rescue of U.S. pilot Captain O’Grady, downed during the Bosnian conflict in the 1990s and quickly rescued because he was able to provide his coordinates from his handheld Flightmate GPS receiver. Today, of course, military receivers would automatically provide the location, and rescue would be even faster.
Pratap also co-authored with Per Enge of Stanford a graduate-level engineering textbook on GNSS. But for the rest of us, GPS for Everyone: You Are Here is available through bookstores everywhere.
Despite being an avowed Anglophile since my first visit to the United Kingdom, somewhere around 50+ years ago, I just could not help myself. Professor David Last, Professor Emeritus at the University of Wales (Bangor) and former president of the Royal Institute of Navigation (RIN) was holding forth, with that wonderful, attention-arresting public school accent, on weighty PNT (position, navigation and timing) matters before an awestruck audience.
Professor Emeritus David Last.
And what did I do? I just could not stop myself reminding him and everyone within earshot that the American Institute of Navigation (ION) predated the British Royal Institute of Navigation by more than two years. The point being, of course, that while two years actually makes little difference in the scheme of things, actuarially speaking we yanks rarely have the opportunity to make such a claim where our stiff upper-lipped Red Coat cousins are concerned. So, when the opportunity presents itself, as it typically does at ION GNSS+, then in my opinion, we former colonists just have to jump in with both feet — or one if by land and two if by sea, and all that.
An even more compelling argument for being first revolves around GPS versus Galileo operational satellites. The first GPS operational launch occurred in 1978, while Galileo has yet to launch a non-R&D operational PNT satellite, into a useable orbit that is. Now, before you accuse me of being smug, I am actually making a case for increased cooperation between the United States Air Force (USAF) and our European counterparts (ESA) where precision positioning, navigation and timing (PNT) schemes are concerned. For when it comes to satellite navigation and PNT, we yanks can definitely declare “been there, done that” mistakes and successes. What better place to “crow,” or rather, impart our considerable knowledge and network with fellow PNT aficionados, than at ION GNSS+.
ION GNSS+
All vocal eloquence jealousies and juvenile kidding aside, in many respects the ION GNSS+ event is actually the epitome of international cooperation in the PNT and GNSS (Global Navigation Satellite System) arena. This annual premiere event is described as “the world’s largest technical meeting and showcase of GNSS technology, products and services,” and I wholeheartedly agree. Indeed, the 2014 event, which took place from September 8-12 at the Tampa Convention Center in Tampa, Florida, had the stated goal of bringing together international leaders in GNSS and related positioning, navigation and timing fields to present new research, introduce new technologies, discuss current policy, demonstrate products and exchange ideas. It was a networking paradise in a wonderful, albeit somewhat steamy, venue, which you can review in two excellent videos concerning the event at the ION website.
This ION conference improves every year in content and attendance, and this year was no exception. Congratulations to Lisa Beaty and her whole team for a great conference, year after year. My favorite events are the annual GPS World Leadership Dinner and the prestigious annual ION Kepler award luncheon. Notice a trend?
GPS World Leadership Dinner
This much ballyhooed event becomes more and more of a draw each year. Tickets are coveted (as scare as hen’s teeth as Granny used to say) and competition is fierce. Every year we have about twice as many people wanting to attend as we have room to accommodate them. So the competition is never boring. This year was special in that one of our own GPS editors was nominated for an award and was overwhelmingly elected to receive it.
The Leadership Award winners this year were Javier Benedicto Ruiz, the Galileo Project Manager from the European Space Agency (ESA), who won in the Satellites category, while an old friend Sherman Lo, who is a senior research engineer and associate investigator (APNT) at Stanford University, won in the Signals category. Our own Eric Gakstatter, contributing editor for Survey and GIS from GPS World, won in the Services category; and finally Oliver Montenbruck, who is head of the GNSS Technology and Navigation Group, from DLR, the German Space Operations Center, won in the Products category.
GPS World 2014 Leadership Trophies.
The invited guests, and there was not an empty seat in the house, heard various perspectives from sponsors Lockheed Martin, Exelis, Raytheon, and Braxton Technologies, as well as visions of GNSS progress from our four award winners.
This event will be covered in much more depth in our December issue, but suffice it to say it was as usual a great event. I wonder from year to year how we will ever top the previous year’s entertainment, which always involves audience participation, but Alan Cameron just keeps coming up with outrageous ideas that seem to always pan out. Hope to see you there in Tampa next year.
The Kepler Award
This year, the highly prestigious ION Kepler Award was won by Dr. Pratap Misra. Even though I am happy to say that through the years many of my friends and colleagues have won this coveted award, I can honestly say, in my opinion, there has never been a more deserving award winner than Professor Pratap Misra.
[Correction: The newsletter summary of this article misspells Pratap Misra’s name. We apologize for the error.—Editors]
Pratap Misra, 2014 Kepler Award recipient.
I have had the good fortune to know Professor Misra for many years, and frankly erroneously assumed, along with many others, that since he is so obviously deserving he had previously won the Kepler Award.
The Kepler Award is presented annually by ION in recognition of an individual’s unparalleled, sustained and significant contributions to the development of satellite navigation. It is the highest honor bestowed by ION’s Satellite Division. Professor Pratap from Tufts University meets and exceeds all of these qualifiers and more. He is simply self-effacing and polite as he quietly goes about being the best in all he endeavors.
Throughout the years, I have found Pratap to be extremely dedicated to his work, and more recently to his students. These are key attributes. Academically, I can honestly say that the authoritative tome Global Positioning System: Signals, Measurements and Performance that he coauthored with, another friend and colleague, Professor Per Enge of Stanford University, is among the most dog-eared in my PNT library. This widely praised volume is often described as a “comprehensive introduction to GPS: the system, signals, receivers, measurements, and algorithms for estimation of position, velocity, and time.” And while it was originally intended as a textbook for senior or graduate-level engineering courses, it also serves remarkably well as a self-study guide for practicing engineers and as a reference tool for writers and researchers. I consider it to be one of the three PNT bibles that are a must-have in every PNT subject-matter expert’s (SME) library. (The other two are Global Positioning System: Theory and Applications, Volumes 1 and 2, by Bradford W. Parkinson and James J. Spilker, and Understanding GPS: Principles and Applications, Second Edition, by Elliott Kaplan and Christopher Hegarty.)
Revised Second Edition by Pratap Misra and Per Enge.
In recent years, Pratap Misra has been honored as both an ION and IEEE Fellow and has served as a past chairman of the ION Satellite Division. He has held numerous volunteer positions within ION, but most recently he has focused on something near and dear to his heart, the support of student programs. This is where Professor Pratap Misra is without peer. Frankly it is obvious that his students adore him, and it is due in no small part to his single-minded dedication to and concern for them.
Every time we meet, the majority of his words and thoughts concerns his students. Their welfare is always uppermost in his priority list. Inevitably, while we are attempting to conduct a quiet and private conversation or interview, we are constantly being interrupted by well-meaning students, past and present, who just want to thank Pratap for his help and support. I could fill up several pages with the technical accomplishments of Professor Pratap Misra, but none of those accomplishments, recognitions or awards mean as much to him as the love, support and success of his students. It is so obvious to anyone who pays attention that he wholeheartedly thinks of his students as and treats them just like family.
I am sure, or at least hope, we all have past professors or teachers in our lives that we remember fondly, and then there are the few or perhaps only the one that changed the course of our lives for the better. Professor Pratap Misra is one of those rare latter individuals, so deserving of the appellation — a professor that made a difference in the lives of his students. I am so proud that he deservedly won the Kepler Award and am deeply honored that I can call him my friend.
GPS-IRT Update
The Global Positioning System Independent Review Team (GPS-IRT) is now officially part of the Independent Strategic Assessment Group (ISAG) under the auspices of the Institute for Defense Analyses (IDA). For 19+ years, the GPS-IRT was a separate team within IDA that researched GPS matters with the “goal of insuring both the military and civilian communities would benefit from new GPS/PNT capabilities and services.”
As a result of this organizational change, Air Force Space Command (AFSPC) chose to formally recognize the GPS-IRT’s 19+ years of effort in support of GPS modernization.
Last Thursday, General John Hyten (USAF), the commander of Air Force Space Command, presented a commemorative plaque to Mr. Kirk Lewis, the executive director at IDA, for both the GPS-IRT and the ISAG. The plaque will be displayed with the GPS satellite on permanent display at AFSPC headquarters, in the James V. Hartinger building on Peterson Air Force Base, Colorado. The plaque contains the names of the four prestigious chairmen who led the GPS-IRT over the last 19 years, as well as the names of the members of the IRT over that same time period. Sadly, two of the chairmen and five of the members are no longer with us, but we can only hope they are looking down upon us fondly and giving us guidance of a different sort.
Until next time, happy navigating, and remember: GPS is brought to you courtesy of the United States Air Force.
The Institute of Navigation’s (ION) Satellite Division awarded Pratap Misra its Johannes Kepler Award on September 12 at the ION GNSS+ Conference in Tampa, Florida, for his contributions to satellite navigation education, the understanding of GLONASS, and receiver autonomous integrity monitoring.
Misra is credited with tracking GLONASS satellites using the AF Deep Space Tracking Network to determine their orbits in the coordinate frame used by GPS, while the satellites broadcast their positions in the Soviet coordinate frame. Misra is recognized for his ground-breaking work on navigation with combination of GPS and GLONASS signals and is the western world’s leading expert on what’s now the Russian satellite navigation system. He was a technical advisor to the Federal Aviation Administration for many of the bilateral and multi-lateral committees that worked on the development of GPS/GLONASS spectrum sharing and avionics.
Additionally, Misra has worked on receiver autonomous integrity monitoring (RAIM), and contributed a novel approach that does not require the simplifying assumption of Gaussian errors. He was also the first to provide a RAIM algorithm that leveraged the receiver clock to put a bound on the vertical position error. These algorithms are expected to play a significant role in the upcoming multi-constellation environment.
Misra is a research associate professor of Mechanical Engineering at Tufts University, and is well known for the textbook that he co-authored with Professor Per Enge of Stanford University, Global Positioning System: Signals, Measurements and Performance. Misra is a past chair of the ION Satellite Division and has held numerous volunteer positions within ION, most recently focusing on the support of student programs. He is both an ION Fellow (2003) and IEEE Fellow (2007).
The Kepler Award recognizes and honors an individual for sustained and significant contributions to the development of satellite navigation. It is the highest honor bestowed by the ION’s Satellite Division.
