GPS World

Tag: letters

  • Letters to the Editor: Another View of GPS Origins

    [Ed. Note: Mr. Beard’s letter has been significantly shortened — while trying to preserve its principal points and intent — to fit the space available in this print magazine. Here is a PDF of the full text of the letter and all accompanying footnotes. Scroll down for Brad Parkinson’s reply.]

     

    The articles in the May and June issues of GPS World on the origins of GPS by Drs. Bradford Parkinson and Stephen Powers presented a detailed view of the people involved in the development of the GPS Program. This view on the origin of GPS essentially begins with the so-called “Lonely Halls” meeting where Dr. Parkinson and a group of Air Force officers invented the GPS concept that was subsequently developed by the teams of people discussed in some detail.

    Missing from this view of the origin of the GPS concept are the developments and events leading up to the final decision on what was to have been the Defense Navigation Satellite System. The development, we are now expected to believe, originated from an Aerospace Corporation Study of 1964. The major events in the pre-history of the GPS program are not as well known as the events after the formation of the GPS program since, like the Aerospace study, they were classified and not generally available. Many of the documents of that pre-history have become declassified so that a more historical perspective can be made based on the actual documentation of events rather than subjective recollections of events.

    Having worked during that era, I began as a naval officer assigned as the TIMATION project officer, Navigation Satellite Branch, Astronautics Division, Naval Air Systems Command, from 1968 to 1971. After separation from active duty I began working at the Naval Research Laboratory (NRL) in June 1971 in the TIMATION program, through the origination of the GPS Program, the Navigation Technology segment of the GPS program and became the head of the NRL Space Applications Branch in 1984 onwards. I believe I have a unique perspective on the origins of GPS, having participated from the Navy side. In the following I have attempted to describe the evolution of the TIMATION project and events leading up to establishing the GPS Program from the official Navy record.

    It should be evident in this discussion that at the formation of the GPS Program, the TIMATION project ended, and the efforts following at NRL on NTS and space clock development were funded by the Navy as part of a Joint Program under the managerial direction of the GPS JPO. This relationship has been considerably de-emphasized and confused over the years, to the point where very few remember it.

    The TIMATION project originated in FY 1965 as the Rapid NAVSAT Readout project under tasking by the Bureau of Naval Weapons. This Exploratory Development project was to investigate the feasibility of advanced navigation satellite techniques, among which was the concept of using passive ranging. The project included a number of experimental investigations into the concept of utilizing passive ranging based on precise time synchronization between a satellite and user receiver to produce more accurate and rapid positioning. An experimental satellite was developed and launched into low earth orbit for experiments in determining accurate satellite ephemerides and demonstrating a simplified technique for position fixing based on celestial navigation concepts. These techniques were intended to demonstrate, but were not limited to, two-dimensional positioning. Position fixing utilizing the celestial navigation plotting technique also determined the time offset of the clock in the user receiver so that it could be corrected for positioning or applied to time transfer techniques. An atomic clock was not required. A number of navigation and time transfer experiments were performed with this first satellite and data was collected for analysis of the concept. Another satellite was designed to incorporate the lessons learned from the first satellite and to perform other analytical studies. It was ultimately launched in 1969.

    However, in 1968 the Joint Chiefs of Staff (JCS) formed a Navigation Requirements Panel to conduct a study, the results of which were approved on 24 September of that year. The new joint service navigation requirements established by this study included the ability of a user to precisely position themselves in three dimensions and precisely determine their velocity, continuously and worldwide. During the year following establishing of these new JCS requirements, the TIMATION project was expanded to address these new joint service navigation requirements.

    Consequently, from 1968 through 1970 the TIMATION concept grew from a category 6.2 exploratory development project into navigation satellite techniques to a 6.3 advanced development system concept employing a constellation of medium altitude satellites containing space qualified atomic clocks to a worldwide distribution of various, surface and airborne, passive ranging user equipment. Technical design studies conducted were designed to analyze or experimentally demonstrate the technical aspects proposed to be selected for the DNSS. The specific technical areas that were investigated were: specific frequencies to be used, single or dual frequencies, and the propagation errors associated with their use; arrangement of the constellation of satellites, total number required for worldwide coverage and quality of coverage; ground stations necessary to operate the satellites and their location (foreign soil or U.S. territory); ranging signals to be used, the accuracy provided, resistance to countermeasures and vulnerability to such things as multipath reflections into a simple user antenna; and capability of being denied to the enemy.

    The Navy and the Air Force 621B concepts were the two principal competing DNSS concepts for providing accurate three-dimensional navigational capabilities.

    In 1970 the Astronautics Division of NAVAIR, sponsor of the TIMATION project, requested preparation of a system development plan to include a demonstration phase which could directly transition into an operational system. Such a plan was required for the Advanced Development phase (category 6.3 funding) of the project, which began with the establishment of the Advanced Development Objective (ADO) 34-11X, the requirements document for the project. The plan described the project requirements, approach, and objectives in some detail. In their guidance letter to NRL, NAVAIR provided guidance on the content of the development plan. The primary technical requirement for the effort was the “Precision navigation requirements in Phase I of the JCS Navigation Study approved 24 September 1968. — The most stringent requirement (being) user three dimensional position within the stated accuracies continuously on a global basis.”

    [Ed: A detailed sequence of events, meetings, and memos excised here are fully viewable in this PDF.]

     

    At NRL a GPS program office (Code 7907) was set up in March 1974 to coordinate GPS activities with the GPS JPO and manage NRL program activities. [ . . . .]

    The development of space qualified atomic clocks at NRL, which had recommended and initially focused on cesium standards, began with the experimental rubidium standards on NTS-1. It was originally intended for experimentation with improved quartz crystal standards. The opportunity to include experimental rubidium clocks on NTS-1 presented itself some eight months before the satellite was completed. A new small rubidium frequency standard, model FRK, from Efratom of Munich became available and even though they were not specifically designed for space
    their small compact size and design was attractive as a candidate space clock. Several of the FRK models were purchased from Munich, evaluated and modified for a space experiment in NTS-1. Two units were integrated into NTS- 1 and operated alternately with the primary quartz crystal standard. This same Efratom Model FRK was selected and proposed by Rockwell International for use in their Block I satellites. [. . . . ]

    The clock development conducted and proposed by NRL was the subject of special program interest during these formative years. In February 1974 DDR&E in a memorandum to ASN (R&D) pointed out that “One of the most vital efforts in the recently approved NAVSTAR Global Positioning System (GPS) is clock development. Funds have been programmed under PE 63401N, NAVSTAR GPS, for programmatic developments defined in the DCP. However, there is a small, but important, effort which should be undertaken … I refer to the development of Space Qualified hydrogen maser clock and its correlative counterpart for the ground control station.” These funds mentioned and subsequent development efforts were Navy funds as part of the GPS joint development effort. The importance and emphasis on space qualified atomic clocks was highlighted in the DDR&E expansion of the GPS Phase I program to support the Submarine Launched Ballistic Missile Improved Accuracy Program. In that memo DDR&E called upon the Navy “to expand their NAVSTAR clock development effort. To reduce risk and provide timely NTS-2 support for the expanded satellite program the Navy should provide a second, parallel, cesium clock development, to be done by an aerospace contractor, for use on NTS-2. If either or both of the cesium clocks perform satisfactorily, cesium clocks should be used in any satellites subsequent to the initial six. The Navy NAVSTAR program should also provide in FY 1976 and beyond for (1) a hydrogen maser development for the NAVSTAR ground stations, and (2) efforts leading to a space qualified maser suitable for NTS-3 and future satellites.”

    Considerable documentation and other material describing the extent and contributions to the GPS program resulting from the TIMATION development beginning in early 1974 could be further detailed. But in the interest of keeping this letter relatively brief those aspects will be covered elsewhere.

    It should be evident in this discussion that the TIMATION project ended at the formation of the GPS Program. The subsequent NRL efforts on NTS and space clock development were funded by the Navy as part of a Joint Program under the managerial direction of the GPS JPO, however, many of the fundamental concepts and approaches began during the TIMATION program.

    It is worthy to note as well, that over the years in addition to the recognition afforded Dr. Parkinson as the first program director of the GPS program, the contributions by Roger Easton and NRL have also been recognized. This recognition includes NRL being included as a major contributor to GPS in the Collier Award of 1992.

    — Ronald L. Beard
    Head, Space Applications Branch,
    Space Systems Development Department,
    U.S. Naval Research Laboratory,
    Washington, D.C

    Brad Parkinson replies:

    I have great respect for Ron Beard and the many other fine engineers and spacecraft developers at NRL.

    That said, I respectfully submit that the letter completely misses the point. There was a substantial amount of Pentagon infighting up to the time I took over the Program in late 1972. Ron has done a great job in documenting this cumbersome history. It accurately shows the paper trail from the NRL point of view. Dr. Currie reset the direction when he designated me to lead the Joint Program in 1973. The past assignments were essentially overtaken by that decision. There is another set of paper, that could be dredged out of the USAF files, but to little point.

    The central issue is not paperwork. It is who conceived the concept, demonstrated the technique on the ground, and built the prototype system.

    With a wave of the hands, NRL declares their system was also three-dimensional, yet the Easton patent clearly was not and the patent was clearly burdened with a militarily-
vulnerable signal structure. Apparently they disown their own preferred design. Yet, the patent is the clearest public record of NRL thinking.

    The letter ignores:

    • 
The first clear explanation of the tradeoffs between the various space navigation alternatives was the 621B “Woodford and Nakamura” study of 1964/66. It included the three-dimensional technique we selected in the final GPS design.
    • The essential keys were: A. Single frequency transmission (CDMA) and B. Simultaneous ranging to four satellites. Both keys were conceived by 621B and demonstrated by the White Sands testing of real hardware (1970/1973). This became the basis for the GPS design in 1973. It is also the basis selected for all of the “copycat” systems by other countries (Russia has now announced a CDMA signal). NRL cannot point to any advocacy of such a system.
    • 
NRL was indeed (as Ron points out) charged with clock development (but their spacecraft CDMA transmitter was provided by the JPO, not by NRL). Note that the early 621B study advocated atomic clocks in space for the system. NRL was not able to provide a useful space-borne clock until the fifth GPS prototype satellite. This was after the Rockwell/Efratom clock had become the only operational satellite clock used in the first four prototype satellites and after the GPS system testing had gained approval to proceed to full-scale development in 1980. Problems with the NRL test satellite precluded its inclusion in the test constellation.

    It is correct that NRL advocated a MEO system, similar to the one we adopted for GPS. The Air Force’s 621B had wanted to demonstrate the four-dimensional technique using spacecraft, and launching the system a world-sector at a time. There are pros and cons both ways, but the controversy was both political and technical. The key to our selecting the GPS MEO constellation design was that it enabled the 4-6 satellite sub-constellation that was star (not solar) synchronized and that technique can be attributed to Major Gaylord Green of the Air Force. This allowed the extended testing on our well-instrumented range at Yuma Proving Ground.

    In 1973/74, my problem was to find a way to advocate the right system without re-igniting the NRL/621B warfare. At that time, I chose to ignore most of the true 621B heritage of the JPO proposal and, in public, talk up the NRL contribution. A number of my colleagues in Aerospace and the old 621B were very perplexed with my behavior. I felt it was the right path to allow us to proceed with actually building the system.

    I genuinely supported the NRL clock technology efforts, and was very disappointed when they were not able to meet our schedule. The space-qualified cesium clock, developed under NRL/Bob Kern, was a phenomenal accomplishment in spite of being late.

    — Bradford W. Parkinson,
    Edward C. Wells Professor of Aeronautics and Astronautics (Emeritus)
    and Hansen Experimental Physics Laboratory
    Stanford University, Stanford, California

  • Letters: L5; An Advisor Bids Farewell

    The L5 Signal

    I wish to second Jim Spilker’s comments in his recent letter to the editor regarding the two wonderful GPS history articles by Brad Parkinson. My endorsement of his comments also includes those about the origins of the L5 signal with reference to the 1999 paper by Spilker and Van Dierendonck, “Proposed New Civil GPS Signal at 1176.45 MHz.” Jim commented in the letter that “. . . . the work I did in designing the GPS L5 signal was performed as a gift to the U.S. Air Force, Federal Aviation Administration, and our country, . . .” It was a generous contribution, and I applaud it.

    However, this leads me to comment on other very important but underreported gifts to L5 and subsequent signal developments. A small indication of the L5 contributions is given in the brief acknowledgement at the end of the referenced paper, “The authors wish to acknowledge the contributions of Dr. C.R. Cahn and Thomas Stansell in the selection of this signal.” It also is important to recognize that the L5 signal structure was formulated within an RTCA committee of mostly volunteers. Among other key participants, in addition to A.J., was Dr. Chris Hegarty.

    The L5 signal design included several innovations which influenced subsequent development of modernized GPS signals and of signals for other GNSS. My ranking of the most important L5 innovations is:

    • Center frequency of 1176.45 MHz in an ARNS band
    • Two signal components, one with a data message and the other without (pilot signal)
    • Forward error correction (FEC) (first GPS use, borrowed from WAAS)
    • Overlay code to frame symbols and eliminate need for bit synchronization
    • CNAV message structure for better accuracy and more flexibility

    The list doesn’t include the 10.23 MHz code clock rates or having two signals in phase quadrature, which were included in the first GPS satellite launched in 1978. The new center frequency was recommended by Karl Kovach (then with ARINC and now with Aerospace) and adopted before the signal design began, but it was central to the L5 purpose of having a civil signal in an ARNS band. This same center frequency also will be provided by Galileo and Compass, so it was a vital innovation. Although forward error correction had been adopted for WAAS, the first use on GPS was the L5 design. In one form or another, it too will be used on most if not all other GNSS signals.

    The second and fourth innovations in the list above were contributed by Dr. Charlie Cahn with help and encouragement from Richard (Rich) Keegan and myself. Having a dataless or pilot signal provides a significant boost to performance and has been adopted for almost every subsequent GNSS signal. The problematic C/A bit synchronization process has been eliminated by the data symbol overlay code (or equivalent) in all subsequent signals. The CNAV message format was principally developed by Karl Kovach with significant help from Art Dorsey of Lockheed Martin.

    In summary, Brad Parkinson helped memorialize many of the early “GPS Heroes” who made GPS what it is today. Other heroes have contributed to GPS modernization, and credit should be given where credit is due. Brad mentioned Charlie Cahn, one of my real heroes, who helped shape the 621B and early GPS signals and has continued to contribute in many ways. In addition to the very significant innovations mentioned above, Charlie was key to similar improvements made in the subsequent L2C, M-code, and L1C signal designs.

    — Tom Stansell
    Kauai, Hawaii

    An Advisor Bids Farewell

    Paul Cross
    Paul Cross

    Many thanks for the kind invitation to GPS World’s Leadership Dinner. I have to decline as I won’t attend ION-GNSS this year. I will retire from University College London at the end of September. I don’t plan to remain active in the world of GNSS after my retirement so this would be a good time for me to step down from the Editorial Board. I’ve very much enjoyed my association with GPS World and have benefited enormously from it.

    I wish you and the magazine continued success. You have come a long way over the past twenty years or so and you are now, and have been for some time, the premier source of news (and very useful gossip!) relating to GNSS worldwide. I don’t know anyone of any significance who doesn’t read GPS World every month. Your highly accessible technical articles have been of enormous help to many cohorts of students here at UCL, and all over the world.

    Take care and stay healthy! All the very best,

    — Paul Cross
    London, UK

  • Are You a Professional? Follow-up Letters and Using GIS for Commercial Real Estate Market Research

    I’m happy that last week’s article titled “Are You a Professional?” evoked responses from readers. I thought I’d share a couple of the responses I received. Also, I’ve included a good piece on using GIS for commercial real estate market research.

     

    "Are You a Professional?" letter to the editor from an independent GIS consultant:

     

    A comment on your piece on professional. I have generally thought of professional as a simple English word that contrasts with unprofessional, and that’s what I think you were saying, too. Only when I started working with people who have to be registered and licensed did I come to understand that some people associate being professional with being registered and/or licensed.

    Part of the confusion may be the English language: the words profession and professional sound very related. I grew up with the idea that a profession is something requiring special education and training, and the examples were always doctors and lawyers and teachers and ministers. By this definition, house painting could be a profession for someone who applies effort to learning about all of the different products and their uses and when they will fail and so on.

    Wikipedia gives this: "A profession is a vocation founded upon specialised educational training, the purpose of which is to supply disinterested counsel and service to others, for a direct and definite compensation, wholly apart from expectation of other business gain."

    That part about disinterested counsel could be an important piece of the confusion/distinction/pride?

     

    "Are You a Professional?" letter to the editor from a state government GIS Specialist:

     

    In response to your article "Are You a Professional?" I would like to note that I work in state government.  In civil service we have "professional" working titles and "secretarial" working titles. So, by default, I am considered a professional because of my particular title — which is a GIS Specialist.  But personally, I feel that there is a difference between conducting oneself as "professional", and actually being a "professional." If you conduct yourself as a professional, using the word as an adverb, you could be considered as such, in any job you hold. There is a professional manner of dress and conduct required to elicit respect from both your colleagues, and your clientele. However, when using the word as a noun, a professional used to imply, though perhaps not by official definition, that a person had an advanced education, or extensive experience, to some degree. They may not hold a PhD, but they would probably hold some type of degree, or possess extensive years of service in a particular field. I have both a degree in Graphic Design and almost 20 years of experience in the mapping industry, so I feel I am a professional for a multitude of reasons (none of which involve salary, as that is really negligible at best).
     
    Also, I can completely understand where Gretchen Peterson is coming from in terms of her issues with map design, because I have had similar moments of exasperation at the poor design aspects in maps containing very complex datasets.   Having experience in both the design and the analytical aspects of mapping, I have a better understanding of both areas.  And although I consider myself a professional, I would not consider myself an expert of either.  I have created maps since the days of scribe coat and Leroy lettering guides. I have remained in the field through the various computerized incarnations of digital mapping, including command line driven Sun Microstations, to the current Windows driven applications we have today. One thing that did remain consistent through it all, was the aspect of map composition and design, which is very often overlooked. I feel some type of graphic design courses should be part of a required curriculum for a Cartography, or GIS major, at any university. Or, at the very least, as an elective listed along with the course of study.  Another frustration I have with the industry is the lack of understanding, of both the technology and map design, on the part of the clients that require the work.  There are those that only worry about the "eye candy" factors without understanding the work involved in the actual data.  And there are those that don’t care if a map is almost illegible, because their main concern is the content of the data, as opposed to its visual interpretation.   A person working in this industry should really be able to wear a variety of hats in order to completely convey their intentions to an audience with any type of data.  It is necessary to understand both your medium, and your audience, to achieve the most understandable and artistically rendered presentation of such scientific information.  It’s a true mix of science and art, and quite often grossly misunderstood.

     

     

    Following is a short piece from Esri writer Karen Richardson. I first met Karen at Esri’s Redlands office in the mid-90’s. When discussing the issue of position accuracy with land surveyors, I often use the commercial real estate example to illustrate how GIS can be a powerful tool even if the spatial accuracy is not within a centimeter, or even a meter, or even five meters.

    Using GIS to Improve Market Research in Commercial Real Estate

    Edens & Avant owns, operates, and develops community-oriented shopping centers in primary markets throughout the East Coast. More than 130 centers in 14 states make up its portfolio. The company’s clients include regional and national retailers such as Fresh Market, Whole Foods, Publix, Starbucks, and Target. The success of the company’s shopping centers is based on generating the best mix of retailers and creating high-profile developments that are optimally aligned with neighborhood need and market opportunity. Edens & Avant is headquartered in Columbia, South Carolina, and has regional headquarters in Boston, Massachusetts; Washington, D.C.; Atlanta, Georgia; and Miami, Florida.

    Seeing a Place through Data

    Edens & Avant required a system to research markets and locations as well as a platform to quickly market that information to prospective retailers. Whether a retailer is looking to open a new store, add a second store, or move from across town, the company has to be ready with a strong case for the retailer to move into an existing shopping center or a new development. Purchasing one-off reports to research each shopping center becomes inefficient when dealing with hundreds of locations that have rapidly changing information like demographic data.

    In addition, instead of banking on the promise of growth driven by the housing boom—the standard model a few years ago—developers must now develop projections based on less robust growth and more conservative economic projections. "Healthy shopping centers are the ones that are located in markets with a diverse workforce and good balance of daytime-to-household population," says David Beitz, director of geographic information systems (GIS), Edens & Avant. As a result, the company needs to analyze, aggregate, and display accurate demographic information on a daily basis.

    Use the Find Similar feature to identify new markets
    that are similar to markets in which retailers are already successfully operating

    Better Decisions through Mapping

    Edens & Avant uses Esri Business Analyst software on the desktop and online to help its clients make the most informed decisions. Clients can see and understand all information available for each shopping center location, including address, major roads, competition, population density, and growth. Business Analyst Online (BAO) is used to generate a customized six-page report annually for each shopping center that is then used by investment leasing and development group agents so they can better visualize and understand their markets. The software helps identify new markets that are similar to those in which the retailers are already successfully operating. If staff members need customized reports or maps, they can request them from the GIS group.

    Integration with Bing Maps provides monthly updates to aerial, road, and hybrid (aerial with labels) maps. "Using Business Analyst and Bing Maps, we are able to find locations fast," says Beitz. "Being able to view aerial images allows us to give a better context to our clients about location. This is particularly helpful when looking at larger areas."

    The company looks carefully at optimizing its shopping center portfolio by selling properties in secondary and tertiary markets and buying properties in primary markets with dense populations in core-based statistical areas (CBSAs). Business Analyst is used to look at daytime population, income changes, and population changes, among other information. "It is very important to know the demographics in order to find areas that will perform best in this new economic climate," says Beitz.

    Imagery combined with GIS software and other data make it easier to find the best store placement for retailers

    Combining city data with updated demographic data ensures Edens & Avant has the most current information for their clients

    Results

    Edens & Avant can now serve its clients’ needs internally without outsourcing to third parties. They can research markets and assist in quickly leasing space by providing spatial information via maps and reports that uniquely characterize neighborhoods and are specific to each retailer. The ability to combine city building permit data ensures that Edens & Avant has the most current information for its clients. As a result, two planned grocery-anchored shopping centers are going forward in areas where population doubled even though residential construction recently slowed down. Being able to find and track this growth with Business Analyst allowed the company to minimize the carry time of the land and provide the shopping center sites based on the retailers’ timelines. Concludes Beitz, "Without the information to support these decisions and an accurate and appropriate way to communicate it, these projects wouldn’t have been as successful."

    Karen Richardson of Redlands, California, is a writer for Esri.

    Thanks, and see you next week.

    Follow me on Twitter at http://twitter.com/GPSGIS_Eric

  • Letters to the Editor

    Our readers respond to the cover features in the April, May, and June issues: the two-part special the “Origins of GPS” and Richard Langley’s look at “GPS by the Numbers.”

     

    GPS0610_Cover
    Source: GPS World

    Spilker and Parkinson: from GPS Origins to L5

    Thank you so much, Brad, for the recognition you gave me in your history of GPS origins in the May and June issues.

    I keep in my sometimes near photographic memory the numerous hours and trips we made over these many years, especially in the early days when you were Joint Program Director of GPS, the meetings we had with Bob Cooper and the Navy admirals. You

    offered me the opportunity of a lifetime to contribute a little.

    The one thing that you did not mention because of modesty is your ability to put together a team of Air Force officers so outstanding that I have not seen a comparable group anywhere else.

    There is at least one other contribution worthy of inclusion, later in the program. One day during a board meeting at Stanford Telecom, I pointed out to Bill Perry that Congress had just zeroed out the GPS budget. He immediately got on the phone to the chairs of the House and Senate Armed Services Committee. Sam Nunn was chair for the Senate, and after much work and many calls, talked them into reversing that decision.

    I have often thought that had the two parallel Navy Timation and Air Force 621B programs not been folded together as a single joint program, neither program would have survived.

    On another subject, I think there is still work to be done on precision interoperability of multiple GNSS. How does it relate to “bounded inaccuracy” and integrity and precision positioning and carrier-phase precision?

    Finally, many probably do not know it, and I have not received any recognition for it, but the work I did in designing the GPS L5 signal was performed as a gift to the U.S. Air Force, Federal Aviation Administration, and our country, with no compensation of any kind including my travel to the ION conference where I gave the award-wining L5 paper with AJ Van Dierendonck.

    [See J. J. Spilker and A. J. Van Dierendonck, “Proposed New Civil GPS Signal at 1176.45 MHz,” Proceedings of ION GPS-99, Institute of Navigation, and an earlier, similar paper at the June 1999 ION Annual Meeting. — Ed. ]

    GPS0410_Cover
    Source: GPS World

    I only mention it now because of the successful Block IIF launch. I ask nothing in return, and only hope it is of some value to our country and the world.

    — Jim Spilker, Jr.
    Half Moon Bay, California

    Brad Parkinson replies:

    Thanks to both you and AJ. It will be an outstanding addition to civil (and I hope military) options. Thanks also, of course, to the groups that ironed out the myriad of important details.

    You also deserve credit for the initial work on split spectrum. Recall we suggested it for the civil signal to attain separation, and it was immediately endorsed and selected as the basis for the military L(M) signal.

    — Brad Parkinson
    Palo Alto, California

    Selling GPS

    Reading your two-part history of GPS origins recalled another story about those early years, and an influential Air Force officer.

    Major General George Keegan was one of the most interesting people I met in my 35 years of Air Force civil service. Primarily an intelligence officer, he was considered one of the leading authorities on the Soviet Union, had been military attaché in the American Embassy in Moscow, and had just been given interim assignment as Director of Plans and Programs, HQ Air Force Logistics Command. He probably did not know anything about logistics, but he had a large staff to help him.

    It was soon evident that he liked to come out to California, ostensibly to see his troops there (my office). What he really wanted was to go to the RAND Corporation in Santa Monica, the first non-profit brains factory set up in 1946 to guide the military services. RAND had a group of retired generals and admirals who war-gamed all sorts of scenarios to test various plans and to critique experiences leading to recommendations for changes. This was stimulating and valuable to him.

    I was in charge of arranging his visits, and he was highly interested in the programs underway and especially in development at the Space and Missiles Systems Organization, where I worked. I would arrange briefings for him and occasionally drive him to our offices outside Norton Air Force Base near San Bernardino where the ballistic missile programs were developed.

    We were collocated with the SAMSO Development Plans shop on the 4th floor of the Aerospace Corporation headquarters building when he called to set up a visit. He asked me what he had not been briefed on. I thought of one program, then called 621B, and told him it was a study area with a lot of promise. He asked me to set it up.

    The “Program” was one lieutenant colonel in an office up the hall from us. He was managing several contracts to explore and develop the concepts for operation and conceptualize the hardware for development of what is widely known now as GPS.

    The lieutenant colonel, whose name is lost to me, was not enthusiastic about briefing Gen. Keegan. I told him he was going to be on the Air Staff, he had security clearances for everything, and he would be smart to accommodate him. He agreed, but obviously reluctantly.

    When General Keegan arrived, the lieutenant colonel started to describe the program as then projected. Gen. Keegan was obviously excited at what he was hearing, and he started throwing questions.

    As a little background, knowing where you are precisely and being able to use that information is one of mankind’s oldest problems, and for the military forces, it is of the highest value. Among the many guidance systems in the inventory were Loran, OMEGA, TACAN, and many others. The annual costs to develop, maintain, improve, and operate these ran into hundreds of millions if not billions of dollars, and all of them operated with severe limitations.

    General Keegan asked, if 621B were developed and deployed successfully, would it supplant and obviate the need for Loran? He got an extremely reluctant answer, yes. Would it replace TACAN? Same answer. OMEGA? Same answer.

    I remember him sitting there staring at a very discomfited lieutenant colonel. He said, if I recall his words correctly, “Colonel, you don’t know what you have here. I don’t think you realize its importance. I will just have to sell it for you.” Later, when the General had left, the lieutenant colonel asked me if he was kidding. I replied that, from what I knew of him, he meant what he said.

    Fast forward now about two years. General Keegan was the Intelligence Chief, HQ U.S. Air Force. Program 621B had progressed, had several people in the development planning process, and was ready to expand greatly if funding were provided by the Department of Defense. It was in competition with many other Air Force, Navy, and Army programs, and there wa
    s no assurance that all would be approved.

    At that time, possibly even today, there was an annual Department of Defense conference to allocate funds called the Defense Systems Acquisition Review Committee, or DSARC. Each agency presented its case. The 621B program chief was there (I now recall him to be Col. Parkinson, from reading the article), and he came to see us after the meeting in Washington. He was euphoric, and he wanted to know who General George Keegan was. I told him of the briefing I had arranged with his predecessor several years ago, and what Keegan had said. He said General Keegan had come through in spades.

    This is second-hand reporting, but what happened was that before the DSARC began, General Keegan, who was not a member, asked the chairman for permission to address the group. What he said was something like this:

    “Perhaps once in your lives, if you are extremely fortunate, you may have the opportunity to influence a development that may truly benefit your country. Today you have an opportunity to foster a program that will not only be of enormous value to all the armed services, but provide the answer to one of man’s oldest problems. Program 621B will give the military capabilities that will surpass anything ever imagined, and give the civilian world a spinoff of obvious immediate value and unlimited future potential. Whatever else is approved today, this program should be considered vital.”

    The program director said General Keegan’s remarks were delivered with passion, and when he had finished and left their room, everyone looked at each other. He said their presentation was made easy — they were asked a lot of questions, and they had the opportunity to fully describe the timing, the impact, and the significance.

    The result was they were not only fully funded, but they were told that if they could use more funds later, to let them know. He said after that speech, there was no question in anyone’s mind that there would be a wide open road for their program.

    One of the rewards of my job in those years was being aware of and sometimes, in some way, involved in many fascinating events and programs. In this case, I inadvertently set in motion a chain of circumstances that, in a small way, may have facilitated the development of one of the most rewarding developments that came from the space and missile programs of the 1960s, ’70s, and ’80s.

    I did not sell GPS, but, unknowingly, I helped.

    — Don Hallwerck
    Long Beach, California

    GPS0410_Cover
    Source: GPS World

    Let Me Count the Waves

    I read your publication with great delight but little understanding — with the possible exception of Mr. Langley’s contributions, especially “GPS by the Numbers” in the April issue. Fiddling with my calculator years ago, I quickly found pi to eight digits using 355/113. Do you suppose Mr. Langley has a better simple m/n?

    — John Woodcock
    Bellevue, Washington

    Richard Langley replies:

    Thanks for your message and kind words about GPS World. Fraction approximations to pi is an interesting topic, one that I didn’t have much room to write about in the numbers article. Your use of 355/113 as a good approximation for pi is one that has been known for awhile. It was first discovered by the Chinese mathematician, Zu Chongzhi in 480 A.D. It is good to seven digits. You need more than an 8-digit calculator to show this, though. Type 355/113 into the Google searchbox to get an answer to 9 digits and you’ll see that only the first 7 are valid. It’s somewhat more complicated, but the fraction 103993/33102 gives pi to 10 digits. These fractions can be derived from the continued fraction representation of pi. For a discussion of that and many other interesting facts about pi, see Wikipedia.

    I have received the latest issue of GPS World. What a remarkable accomplishment! An outstanding example of sustainability, commitment, impact, and excellence! The Innovation column has constantly been a source of inspiration and ideas for all, not least GNSS students around the world.

    If ever you have the chance to collate them in one single pdf file and put it on your website or/and that of GPS World, this would be a most valuable contribution and worth more than many books on the subject I can think of!

    Congratulations, and may we see you on the front page for the 300th column!

    — Gerard Lachapelle
    University of Calgary, Canada

    Just read your “Numbers” article. I enjoyed it very much, especially because I am writing java code for an SDR-GPS-receiver I am building. As a starter I am trying to decode Kai Borre’s data file. I just finished implementing parallel code search using FFT. Gives remarkable insight in DSP. I am a retired engineer and radio amateur PA1KDG. Keep on writing and I’ll keep on reading — promise.

    — Kees de Groot
    Wageningen, The Netherlands

    Richard Langley replies:

    Many thanks for your message and interest in the GPS World Innovation column. Coincidentally, one of my students has just finished up a Ph.D. project on designing a strategy for implementing a SDR-GPS receiver and presented his results in April. Good luck with your project.

  • Letters to the Editor: The Other Shoe

    The Other Shoe

    I read Don Jewell’s column in the March Defense PNT newsletter (see env-gpsworld-integration.kinsta.cloud/othershoe), on the troubling concern about GPS dependency, with considerable interest. I thought he made some excellent points, and, in my capacity as a member of GPS World’s Editorial Advisory Board, I would like to present some further thoughts for consideration.

    I thought Don was pretty fair with General Schwartz’ comments, including the thinly veiled reference to underlying Air Force (AF) motives toward a smaller GPS constellation. However, in addition to focusing on the comments of one senior individual, you might also give some thought to the actions and motives of many in both the civil and military communities who have not only failed to embrace but have also resisted the advancement of a National Positioning, Navigation and Timing (PNT) Architecture and the holistic management framework necessary to implement it.

    After 2-plus years of work by 30-plus government agencies (military and civil), an enterprise-level view of the PNT Architecture was presented to the public at the ION conference in Savannah in 2008. Since that time, discussions regarding its implementation have proceeded very slowly within the government. The Architecture contains all the elements you identify as contributing to the “Perfect Handheld GPS,” though, at the enterprise level, many have not technologically matured to the necessary system-of-systems level that would permit acquisition decisions under government rules. As you know, that will take focused technical analysis and trade studies, as well as further development in some cases to bring promising technologies along. Commercial industry does it faster, but its solutions are in most cases unique and proprietary, and not necessarily applicable for use by government agencies, particularly the military.

    You also advocate for more tightly integrated GPS capability, “resulting in impregnable GPS for all users.” That thought pervades the enterprise PNT Architecture, beginning with its foundational recommendation (that GPS remain the cornerstone) and extending through many of the 18 other recommendations which follow. In the Architecture, however, we put a slightly different twist on the objective of GPS integration.

    We recognize that, while GPS service can be improved by increases in signal power, possible additional signal frequencies, and a larger constellation, GPS itself can never become “impregnable.” Rather, by integrating GPS with augmentations and complements of several different types, our objective is to create continuously available PNT of high precision and fidelity from a variety of sources without regard to which particular source(s) is/are contributing to the solution at any particular point. I like to refer to that as “cloud PNT” with a bow to the recent advancements in “cloud computing.”

    Finally, with regard to eLoran, the PNT Architecture envisioned a place in 2025 for an evolved eLoran-type capability, recognizing the possible value of frequency diversity, higher power, signal penetration, carrying 2D position and precise time, all in a relatively low-cost government-provided LF/MF service. Of course, it would have had to compete with other technology alternatives, but that potential course now seems foreclosed. You make the point that the basis for eLoran is, of course, the Loran-C system whose operation was recently terminated by the Obama Administration.

    The most troubling aspect of that termination was the statement in the Federal Register announcement that the DHS would continue an assessment to determine if a single, domestic system is needed as a GPS backup for critical infrastructure applications at the same time it determined that the continued operation of the viable backup represented by Loran was not necessary.

    Go figure.

    — Jules McNeff
Editorial Advisory Board (since 1990), GPS World

    The Spy

    A prescient reader wrote a comment on the webpage of a recent story about the demise of Loran. See env-gpsworld-integration.kinsta.cloud/rtcm and scroll all the way down. It begins:

     Tso had just installed the last of a series of innocuous-looking boxes in a field some miles to the west of New York City. . . . It, and the other 299 units like it, had a single purpose. It was so simple, and it had been handed like a gift to him by the U.S. government itself. . . . .

    The Other Spy

    I loved your blog, “The Spy Who Loved Me” (see env-gpsworld-integration.kinsta.cloud/wideawake).Please make sure to keep us updated if there is any follow-up from him!

    — Brett Buyan, Santa Barbara, California

     

  • Letters to the Editor: Smartphone Revolution

    Nice article on “The Smartphone Revolution” in the December issue. I am not so tech-y about the working of GPS/indoor GPS, but I am interested more in this technology specific to indoor GPS (repeaters).

    Can the smartphones get indoor GPS signals correctly and quickly? If the smart phones are really smart that they can connect to GPS satellite from indoor locations, then do the GPS repeater products become obsolete?

    — Saad B.

    Author Frank van Diggelen replies:
    The simple answer to your first question is yes, many of these smartphones can get GPS signals indoors. But indoors is a big and varied place, and the more complete answer is that the term “indoor GPS,” like “offroad vehicle,” describes the presence of a capability, not the absence of all limitations. So even if your GPS receiver works indoors in some locations, there will always be other places it doesn’t. And it will generally work better where there are stronger signals, like outdoors.

    Similarly, for your second question, high-sensitivity GPS will work some places indoors, but not everywhere, so there is a role for repeaters. However, GPS repeaters are like a long cable from the repeater’s receiving GPS antenna; so any GPS receiver that gets signals from a repeater will compute the position of the repeater’s receiving GPS antenna.

    Nice article. One comment and one question.

    Comment: The IGS ultra-rapids that started in 1999–2000 were from the beginning available for the future. They always contained 24 hours of estimated orbits and 24 hours of predicted orbits usable in real time. As I was responsible for generating these products within the IGS at that time, I am pretty sure that was the case.

    Question: I do not understand why you write that turning off SA (Seletive Availability) was an enabler for A-GPS!? I know that one possible feature of SA was an artificial degradation of the satellite ephemerides but this option was never exercised to my knowledge. So using a global network to obtain broadcast ephemerides and predict them into the future was always possible. Nothing fundamentally changed when SA was turned off!?

    — Tim Springer

    Frank van Diggelen replies:
    Just to be clear, the article enumerated seven enabling technologies for the revolution of GPS in cell phones (they are: A-GPS; massive parallel correlation; high sensitivity; coarse-time navigation; low-power TOW decoding; host-based GPS; and RF-CMOS), and a dominant spin-off technology: long-term orbits good for many days into the future.
    The demise of SA made it easier to predict long-term orbits for two reasons: technical and commercial.

    Technically, if you used the code- or carrier-phase measurements in your orbit modeling, then it was easier if these measurements were not degraded. Of course, you could have corrected them differentially, but the article makes the point that things were harder (not impossible) when SA was on.

    On the other hand, if all you did was use the broadcast ephemeris in your predictions, then as you suggest nothing changed, technically, if the ephemeris degradation option was not exercised. But the fact that this degradation option existed made it a more difficult commercial proposition to develop a system for predicting many days of ephemeris. Thus the end of SA certainly helped facilitate the commercial availability of predicted ephemeris that is valid for many days into the future.

  • Letters

    Below is a letter sent on November 3 by Senators Joe Liberman, chairman, and Susan M. Collins, ranking member, Committee on Homeland Security and Governmental Affairs, to Secretary of Homeland Security Janet Ann Napolitano protesting the termination of the Loran service:

  • Letters to the Editor

    You Go Too Far, Too Far, to Be Honest

    Reaction to August’s editorial, “Fair Play to Those Who Dream,” concerning the as-yet unreleased Galileo signal specification, came swift — and mixed — from both sides of the Atlantic. Correspondents were unanimous, however, in wishing their names kept off the record.

    From Europe:
    “I really think you go too far, too far to be honest.”

    “I truly appreciate your open words. They come right out of my heart. I’m not sure, though, whether they are loud enough to make the European Space Agency and European Union wake up at last.”

    From the United States:
    “. . . ranting sensationalism . . .”

    “Nice job. I think you will get some kudos for this.”

    Interference Counter-Effort Gets Cart Before Pony

    Your May 2009 editorial bemoaned the fact that, despite rhetoric to the contrary, blessed little had been accomplished in our ability to identify and localize sources of GPS interference. Some of my colleagues might describe me as a bit obsessed with this issue, but I think it a healthy obsession.

    The most recent attempt I’ve seen that addresses this issue is a program sponsored by the Department of Homeland Security (DHS). Based on a briefing of this effort that’s available on the Internet, I seriously doubt that this program, as presently structured, has much chance of yielding a useful product. Why? Because I believe the approach to be thoughtless rather than thoughtful. And I mean “thoughtless” in the literal, not pejorative, sense. Those involved in the program, as listed in the briefing, are among the brightest talents available to address this issue.

    My past dissatisfaction with the way the government has treated this issue — at least from the early 1980s — stems from what I call its planning-to-plan mode. An agency would lay out an elaborate plan, replete with words like “coordinate” and “support,” but include few if any specific action items such as “Agency A should develop specific capability B.” So no one was on the line to deliver.

    Preparatory to writing this letter, I thought I would do a few searches to see if there were any new initiatives underway. I was rather pleasantly surprised to see that DHS had produced, and briefed, a study titled “GPS Interference Detection and Mitigation.” That is, until I read it.

    The DHS briefing is a 25-slide presentation. To its credit, it doesn’t plan-to-plan. The brief lays out a procedure to address the issue. But once we eliminate the boilerplate describing the non-specific tasking and coordination, we wind up with roughly seven slides devoted to a detailed description of the central data repository and the logging of data. Excluding a page that vaguely describes potential sources of data without describing how they could contribute to the tasking, there are zero pages devoted to the sensors! But these sensors are the heart of the system, and will dictate the types of data that the central facility must process.

    The problem is compounded since, according to the briefing, the only aspect of the program assigned funding is the central data repository. So we’re putting the seed money into some generic repository? A classic case of buying the cart before the (as yet) undefined pony.
    What’s the problem? I think there are several.

    • First (and I’m guessing here), someone was given a mandate to do something. And with insufficient time to do the necessary thinking. Which primarily requires a few folks closing the door, putting their feet on the table, and actually thinking about the problem.
    • This, in turn, produced a description of a processing/repository center that had to be generic, since without defining the sensors one can’t define the data types, formats, and quantity that the sensor arrays would provide. So how does one spend the repository funding indicated by the DHS study?
    • And, it’s a hard problem. You can’t solve it by just brute force.

    Let me end by suggesting how I would contrast a thoughtful approach from a thoughtless approach to the issue. The thoughtless approach would be to develop a one-size-fits-all solution, by which all data sources will filter through the distribution chain to the repository.

    The thoughtful approach is for one of the guys/girls to eventually take his/her feet off the table, and suggest, “Hey, our major heartburn at this time is fratricide! Rather than spend a lot of time and money reporting this interference, why not adopt procedures for preventing it? And, given we provide a training program in place on potential problem sources and corrective procedures, we might spend a few dollars on the type of jam meter (see Phil Ward’s paper in Inside GNSS, Sept/Oct 2007) to show that violations will be monitored.”

    Under this scenario, with a bit of luck, a potential San Diego (2006) or Rome AFB (1997–1998) event never gets to the reporting stage.

    Is the above the ultimate solution? Of course not. Countering the intentional jamming of GPS will be the larger challenge. But a bit of forethought appears preferable to blindly funding the cart,
    before knowing how the pony behaves.

    — Terry McGurn, Reston, Virginia

    Military Handhelds

    I just wanted to say how much I enjoyed Don Jewell’s column, “The Warfighter and Rorschach Shock.” It is a sad fact that the DoD has not woken up to the potential of a market-driven procurement process for products like handheld GPS. I’m of the opinion that if tamper-resistant SAASM OEM chips or boards were available to the Garmins of the industry, and the military user had his choice of units, we’d see a much superior offering to the warfighter at a lower net cost. Companies like Garmin are not GPS receiver builders, they buy their receivers from companies like SiRF and Broadcom. Their expertise is as systems integrators and they do a superb job of it. Obviously, the warfighter values this expertise and wants to use it — so why don’t we give them what they want?

    — Logan Scott, Breckinridge, Colorado

    Time for GPS 101

    Ijust read Don Jewell’s article “Time for GPS 101.” I too am appalled by the ignorance of the public and, more importantly, of our political decision-makers, not just about GPS (critical enough in isolation) but about a myriad of national and global safety and security issues. As a 30-year member of the aerospace engineering community, I am fearful of the future of our country and society because of bad decisions made by ignorant decision-makers, sometimes supported by technical “experts” who provide bad information and advice, usually from their own ignorance but often cynically from a hidden agenda.

    — Name Withheld

    I truly enjoy Don Jewell’s editorials!

    After reading the GPS 101 column, I wondered: Why is there nothing presenting this technology to children? (If there is, I have yet to find it.) Before their minds turn to mush, I believe if we start them with the basics, coupled with the present technology evolving as fast as it is, imagine what they could be doing with GPS when they graduate from high school! I understand that the teenagers have the iPhone with the hip applications and such, but wouldn’t it be neat to see a seven-year-old with a handheld scouring a park looking for his/her first geocache?

    — John Pollard, Southeastern, Electric Cooperative, Sioux Falls, SD

    I enjoyed your “Time for GPS 101” article. Your point was driven home last night as I watched the National Geographic Channel program, Known Universe: “The Fastest,” when they used GPS in their discussion of the relativistic effects of velocity. To my horror, they described how the GPS receiver sends signals to the satellites which are used to determine your time and space coordinates. The ignorance of the unwashed masses may be excused, but when a channel dedicated to science gets it so wrong, I really worry.

    — John Zander, St. Inigoes, Maryland
     

  • Letters to the Editor

    DAGR Remarks

    In the April edition, an article titled “DAGR Extended” covered news from the Space & Missiles Center regarding the GPS Wing awarding a follow-on contract to Rockwell Collins to provide Defense Advanced GPS Receivers (DAGR).

    At the end of the article appeared an “Unofficial Word,” which made derogatory and inaccurate remarks about the use of the DAGR.

    We are disappointed that the staff of GPS World did not contact us for a response to the accusations made in the article. Had you contacted us, our response would have been the following:

    The DAGR provides the only means for dismounted soldiers or special operators to obtain location information of sufficient accuracy, reliability, and integrity for targeting purposes. Our warfighters use the DAGR to call in close air support missions, which the DAGR delivers GPS-guided munitions with pinpoint accuracy through its Advanced Laser Range Finder and Fire Support functions. The DAGR also provides unique Gun Laying Azimuth Determination applications.

    Use of a commercial GPS in these circumstances would entail significant risk that would be totally unacceptable. No other handheld GPS is authorized, nor should it be authorized, for use in military targeting operations.

    In the combat theater, our soldiers and special operators are working in extremely difficult conditions — environmental conditions where the DAGR functions consistently and provides warfighters with the information they vitally need.

    On April 30, we celebrated the delivery of the 300,000th DAGR, which is proven testimony to the utility and reliability of the product.

    In the future, we’d appreciate an opportunity to respond firsthand.

    — Robert Haag
    Senior Director, Soldier Solutions
    Rockwell Collins

    Don Jewell, Military & Government Editor, replies:

    I could not agree with you more. At the same time, I totally disagree with your comment that our remarks were “derogatory and inaccurate … about the use of the DAGR.”

    The conclusions drawn in that “Unofficial Word” (not, by the way, written by me) came directly from several industry and government warfighter panels (many of them attended by Rockwell Collins), face-to-face interviews, letters, and a plethora of personal e-mails from warfighters over the last 24 months. The results were unanimous: the DAGR, according to our warfighters who have opted not to use it, is too big, too heavy, has limited battery life, a black-and-white screen, is basically obsolete, and has a very difficult, definitely not user-friendly interface. Our interviews and correspondence show that the DAGR, as a standalone device, has been replaced by various GPS handheld or wrist-mounted units, Garmin and Trimble primarily.

    How can I then agree with your comments? Because your letter very carefully only defends the use of the DAGR as an embedded device. Indeed it has been our experience that the only warfighters that consistently give the DAGR high marks are the soldiers using the DAGR as an embedded device: those responsible for directing fire — bombs or artillery on target. In a recent interview session with more than 40 soldiers, only the soldier responsible for directing fire said that he used the DAGR in any capacity. He stated, “For directing fire I use my DAGR because it has the necessary interface for laser designators and communications to direct fire. Other than that, I depend on my Garmin, as does everyone else I know, for a personal GPS unit. The Captain uses the DAGR as an input to the Blue Force Tracking (BFT) system that stays in the Humvee or Stryker vehicle.”

    As I, and many others, in many articles, have said all along, the DAGR as an embedded piece of equipment, with dual frequencies, encryption, and approved government interfaces, serves a necessary and critical function: supplying BFT information and directing fire. As you correctly point out, it is the only approved government PNT source for directing fire. That is a good thing; all information and interfaces needed for the direct-fire mission have been worked out and do not need to be duplicated. Warfighters directing fire use the DAGR because there is no alternative, but for every other purpose for which they rely upon handheld GPS equipment, the DAGR is found seriously wanting. Suffice it to say the design is more than 14 years old, and the unit was dated when first released.

    I have spoken to several Rockwell Collins representatives about my concerns and those of the warfighters over the years, and usually they do not dispute the DAGRs’ shortcomings. However, recently I was shown a picture, by a senior Rockwell Collins representative, of a new Rockwell Collins government GPS unit that impressed me as much as a simple picture of a GPS unit can. I asked for more information and a unit to review and I am still waiting. My problem, and I say this in all sincerity, is not with Rockwell Collins, as I know you built the DAGR to outdated government specifications that were generated in the early 1990s; by Moore’s law that is more than seven generations old by today’s standards. My primary concern is the safety and welfare of our warfighters. I know you can do much better, but the antiquated and non-responsive government acquisition system has prevented you from making changes and updating the poorly designed user interface. Rockwell Collins makes tremendous radios and avionics, which I used successfully throughout my 30-year military career, except for PLGR and DAGR units, which I consistently found to be inferior.

    I consider myself a sophisticated GPS user and have tested more than 80 individual GPS units from manufacturers around the globe, yet I find your equipment and interface totally confusing. So please help me. Send me the new proposed government equipment with the color screen, the new interface, and hopefully new capabilities, and I will gladly review it in the magazine.

    Several of my articles have helped gain waivers from the U.S. government for official use of thousands of commercial and civilian GPS handheld units in theater, mostly military-hardened Trimble units. If you have a great new handheld unit, then please send me an example to review and I will do that. Maybe we can get official waivers to use it in theater. I sincerely hope that is the case.
    The soldiers, sailors, and airmen of the U.S. military have voted by purchasing their own units or by obtaining waivers. Even the newest recruits, whose low salary qualifies them for state assistance and food stamps, spend their money on commercial GPS units. As a very distinguished friend and world-renowned GPS expert said recently in a public forum, “You may not know it, but there has been an unofficial competition among military users for GPS handheld units, and Garmin won.” You have delivered 300,000 DAGRs, but how many of those units are actually in use today as stand-alone devices?

    GAO Report

    In my opinion the “GAO Questions GPS Health” article in the June issue focuses too much on the IIF as the potential problem. The May 14–15 National Space-Based PNT Advisory Board meeting heard a presentation from the DoD on GPS issues and challenges. During the briefing, Brigadier General Hyten acknowleged (as asserted in the GAO report) that there are three somewhat equally scary risks: delay of IIF, delay of OCX contract award, and delay of GPS IIIA. In the GAO report, the real doomsday scenario (in the 2015–2017 time frame) was from a two-year slide on the GPS IIIA program. You should also be aware that the graphs in the GAO report don’t account for two mitigation tools the DoD has in reserve: retired satellite still in space that could be revived (there are three at the moment), and power management as a means to extend satellite life.

    I’m less worried about the first graph in the report that shows a dip in the 2010 time frame than I am about the catastrophic dip in the second chart around the 2015 time frame. I think we have a good chance of having fired our silver bullets by that time and will be much more constrained with respect to available mitigations. It is good you are writing about this as it raises awareness of the issue which could aid in the development of a more robust risk mitigation plan before this becomes a crisis.

    I have been somewhat troubled by the anti-IIF program bias in the overall dialog on the subject. I don’t have full visibility or historical knowledge of what all went wrong there; what I do know indicates there was plenty of culpability to go around between the contractor and the government. I am concerned that too much focus on publicly spanking IIF will detract from fixing the root causes of the dilemma we are in: the requirements development processes and acquisition programs applied to GPS are broken. That is exacerbated by a lack of stable policy with respect to the long-term strategy for GPS development and sustainment. There are definitely lessons to learn from the IIF experience. But the difficulties associated with that program should be seen for what they are: symptoms rather than the root cause.

    — Name Withheld

  • Letters to the Editor: Election Results Disputed

    Editor’s Note: Full transcripts of the pre-election debate are available here: Part 1 and Part 2.

    I hereby notify you that I contest your counting of the ballots of the Signal Party versus the Toy Party. Here are some facts:

    According to your own admission, there were 123 people at the dinner, and you counted 108 votes. The 15 votes that you did not count were obviously cast for me, which makes my count 46 + 15 =  61. My son-in-law voted absentee which you did not count. He officially registered and was part of the meeting. That makes my votes 62, equal to the Toy Party. If you add my own vote, I am a clear winner.

    (I will not bring up the fact that you unfairly did not allow my two grandsons to vote. You cannot use the excuse that they could not write. My daughter could have filled the ballots for them. )

    Even if you don’t count my vote, Tom Hunter was the only legitimate vice president at the meeting. According to the rules, the  VP casts the final vote when votes are equal. He votes for me! You can ask him directly if you don’t believe me.

    Your process was not fair:

    • My investigation reveals that many voters had “hanging chads,” some from Florida;
    • many people voted twice for Greg
    • some dead people voted (I can name them if you want!)
    • You even counted votes of Canadians!
    • The main moderator (Richard) was bribed by Greg! I have photo of Greg buying Coke for Richard and giving him a free Garmin for his car. I copy to Richard and Greg to admit their guilt! Otherwise I will publish the photo of Richard drinking Coke.
    • I may also find your photo drinking Coke.

    This is a serious national security concern. I will bring it up at next year’s meeting and am ready to take it all the way to the Supreme Court if you don’t count the votes fairly!

    There are lots of questions to be answered to the court: Who had custody of the ballots before, during, and after the count? Who were the people who participated in counting the ballots, and what were their qualifications?

    The fact is that the Signal Party won. I demand a re-count!

    — Javad Ashjaee

    Once again, I can only express my deepest disappointment that my colleague would feel the need to drag such a clear outcome through the mud and unnecessary contortion of the legal arena. We all know that does not serve either of our constituencies, but simply enriches the lawyers. I would have expected Mr. Ashjaee to be one of the people who most clearly understood that the will of the people is not subject to the random decision-

    making of the judicial branch. However, as a concilitory gesture to move our great industry forward, I would offer Mr. Ashjaee a seat in the new cabinet as Minister of Accuracy in the Satellite Party government.  

    — President-elect Greg Turetzky

    Editor’s Note: The parties have entered out-of-court discussion to which the magazine is not privy, nor will it entertain any further disputation. Election results stand as announced. However, in the interest of full public disclosure, we wish to allay Minister Ashjaee’s concerns about the identities and qualifications of the ballot guardians and counters.

  • Letter to the Editor: Who Invented GPS?

    In your August 2006 issue, you raised the question: Who was first with GPS? And you concluded that a debate may not be useful. You may be right. In spite of Richard Easton’s Internet claim that his father, Roger Easton, invented GPS by filing an enabling U.S. patent number 378 9409 in 1974, he must have had his doubt. For he preceded his article with a quote by Alexander von Humboldt, who had observed that the third stage of scientific discovery “finally credits the wrong person.”

    From its very beginning, the invention of GPS was teamwork. First and foremost among them were the rivaling research teams of the U.S. Air Force and the U.S. Navy.

    In the 1940s, the navigation system LORAN, still in use by ships today, was developed by an MIT research team while Ivan A. Getting was a researcher at MIT’s Radiation Laboratory. In 1951, Getting became the head of research and engineering at Raytheon Corp. in Waltham, Massachusetts. They developed a mobile ballistic missile guidance system, called MOSAIC. In 1960, Getting was asked by the Air Force to create a nonprofit military systems development organization and became president of Aerospace Corp. While planning new ballistic missile systems, space-launch systems and high powered chemical lasers, he focused on and became an evangelist for Navstar. “GPS was incubated in the mind of Ivan Getting,” noted the National Inventors Hall of Fame when it inducted him and Colonel Bradford Parkinson.

    Everybody agreed, however, that many others were part of the several inventor teams and deserve credit as well.

    Back in 1991, as president of ACSM, I had the opportunity to speak to Col. Bradford Parkinson’s GPS expert, Col. Gaylord Green. He told me that their small team of six or seven scientists had built the GPS architecture in 1972, in less than a month. Air Force team members included Mel Birnbaum, Bob Rennard, and Jim Spilker. The GPS concept and theory had been established earlier as a Transit system, and has always been an “institutional endeavor,” said Green.

    Richard Easton also mentioned James Buisson, Thomas McCaskill, Don Lynch, Charles Bartholomew, Randolph Zirn and “an important outsider,” Robert Kern, as talented team members of his father, Roger, at the Naval Research Lab (NRL). It turns out that the important outsider, Robert Kern, became the founder of Frequency & Time Systems, Inc. (FTS), a manufacturer of atomic clocks for GPS satellites, in Beverly, Massachusetts, in 1971.

    He may or may not be a descendant of the famous Swiss instrument manufacturer Kern A.G., which is related to Wild Heerbrugg of Switzerland, now Leica. In its website, Milestones of Technology, it describes that it had conducted the first feasibility study for the GPS program 621B of the U.S. Air Force in 1967. Likewise, in 1971, it defined, designed, and built early prototype receivers for the Navy’s GPS program Timation. As Gaylord Green pointed out, GPS has always been an institutional endeavor.

    To sum it up, the diverse teams of GPS inventors and designers were led by at least three outstanding American scientists. They are Ivan A. Getting of Raytheon and Aerospace Corporation, who in the 1950s “incubated GPS in his mind;” Bradford Parkinson of the U.S. Air Force, who helped create GPS in 1972; and Roger Easton, of the U.S. Navy Research Laboratory, who filed the enabling patent in 1974.

    Thanks to their joint effort, simultaneously or in succession, we can today look at GPS applications, both military and commercial, where the sky is truly the limit.

    – Gunther Greulich, PLS, PE,
    Former president ACSM

  • Letters to the Editor – December 2006

    Need Clear Vision

    Well done on the editorial this month (“Skies Cloudy All Day,” October). I totally agree with you regarding the lack of clear vision for our GPS future. And I’m not saying there is not vision at the Air Force, but the GPS programs must be backed by the full Congress and its funding. We must put government funding behind that vision to make it a reality. When we as U.S. citizens say GPS is critical to our national security, and even our livelihood more and more each day, we must back that with the bucks to keep it healthy and strong as the utility that it has become.

    – Ellen Hall
    President, Spirent Federal Systems Inc.

    NDGPS Killer App

    This is in response to the October 2006 letter “NDGPS Budget” by Tim Smith and the reply by Erik Gakstatter. There will be a killer application for NDGPS, for ground vehicles to know their position precisely to the meter, especially in the urban canyon setting where satellite reception can be very poor. This effort is spearheaded by the Department of Transportation (DOT) for the Intelligent Transportation System (ITS). In addition, the Vehicle Infrastructure Integration (VII) consortium consists of several state agencies, automobile manufacturers, and vendors to implement vehicle-to-vehicle-to-roadside communications via Dedicated Short Range Communications (DSRC). The primary purpose is to enhance vehicle safety using communications for collision avoidance, signal violation warning, near instantaneous traffic information, and road hazard warnings. In this case accurate GPS positioning is very important and where NDGPS can fill the need. Secondary purposes are to provide a wide range of applications starting with local electronic signage, navigation aids, traveler information, electronic payments (fuel, parking, tollway), ramp metering, and a wide variety of potential consumer applications in the vehicle.

    The article “Safe in Traffic” in the very same issue of GPS World describes the whole project and the use of GPS for ground vehicle transportation, but not the need for accurate GPS positioning which could be provided by NDGPS.

     – Neal W. Probert
    President, ProbeStar Technical Systems

    WAAS in the East

    Could you please tell me when WAAS will be up and running in Eastern Canada?

     – Kenneth Lewis
    Government of New Brunswick

     

    Editor’s Reply: There have been some changes due to geostationary satellite repositioning. See the web page of the University of New Brunswick’s Wide Area Augmentation System Monitoring Station and the Federal Aviation Administration’s “New WAAS GEO Status as of 11/9/06” PDF file.