L5 and Rorschach Shock
- From: Sam Wormley <swormley1@xxxxxxxxx>
- Date: Thu, 14 May 2009 01:06:56 GMT
L5 and Rorschach Shock
http://mg.gpsworld.com/gpsmg/content/printContentPopup.jsp?id=598043
May 13, 2009
By: Don Jewell
GPS World
L5 Update with Col. Mark Crews
I am sure that many of you remember Colonel Mark Crews when he served with distinction as the chief engineer for the GPS Wing at the Space and Missile Systems Center (SMC). Mark made some legendary and landmark contributions to the future of the GPS constellation as we know it, nationally and internationally. His efforts will long be appreciated by those of us who know about them in some detail. Mark is always the gentleman and is reluctant to boast about his feats, so we may have to do that for him. After you read what Dr. Crews has to say about the L5 payload, I will launch into an issue concerning user equipment that has been on mind for sometime.
Mark retired from the U.S. Air Force several months ago and took a senior position with ITT in Colorado Springs, Colorado, working GPS and other space programs. I tracked him down recently and asked him to fill me in on the specifics of the L5 payload that took so long to finally place in orbit. Mark’s comments are below interspersed with a few of my own. I wanted you to see them because Mark writes well for an engineer with a master’s from MIT and doctorate from Oxford. After you read what Dr. Crews has to say about the L5 payload, I will launch into an issue concerning user equipment that has been on mind for sometime.
The GPS space vehicle IIRM-20/SVN-49, NAVSTAR #63, which was successfully launched on March 24 at 4:34 a.m. EDT from Cape Canaveral Air Force Station, Florida, carries an important payload to demonstrate the new L5 civil signal. The primary purpose of the L5 demonstration payload is to secure frequency filings and protect this part of the spectrum for civilian users worldwide. Unlike other GPS signals, the L5 signal is not multiplexed with other signals. Rather, it is a dedicated civil utility in the ARNS band.
The L5 demonstration signal at 1176.45 MHz employs BPSK-R(10) or Binary Phase Shift Keying spreading modulation with a specified minimum received power of -154 dBW. This essentially safeguards the L5 spectrum with higher power in a wider bandwidth. Subsequent L5 payloads on the Block IIF satellites, when they are launched, will provide additional L5 navigation signal utility. While the demonstration L5 signal does not provide a message capable of being used for navigation purposes, it can and is being monitored by sites around the globe.
Note: The first IIF payload was finally sent to the Cape on May 7.
In March 2007, ITT was put on contract to develop the L5 demonstration payload on IIRM-20. The L5 payload was constructed by ITT from an existing L2 space-qualified payload. The primary new components required were an L5 filter as well as L5 SMIC (synthesizer — modulator — intermediate power amplifier — converter). Due to the GPS satellites (LMCO) flexible bus design, the L5 experimental payload was fully accommodated without any major modifications. As a result, all necessary L5 payload interfaces were readily available for power, telemetry, commanding, timing, and broadcast.
The Air Force, LMCO, and ITT contractor, scientific, engineering, and management teams successfully integrated the L5 payload in record time and conducted numerous integration and compatibility tests to ensure mission success for IIR(M)-20. The space vehicle is currently on orbit and broadcasting the L5 demonstration signal.
There is, however, a very minor problem with the L1, L2, and M-code navigation signals. Any causes would be pure speculation at this point, but the issue is the satellite will not be set healthy until these problems are fixed. Actually, the legacy navigation signals are well within specifications, but are not of the quality we have come to expect from the excellent IIRM payloads. The ITT, LMCO and GPS Wing teams are working the problem hard. It may be a few weeks before the satellite is set healthy, but when that time comes I am sanguine that all the signal issues will be mitigated and the navigation message will be on par with the other IIRM payloads. Meanwhile the L5 signal is strong and clear and it meets all the ITU requirements for successful registration of the L5 frequency. — Colonel Mark Crews
The Warfighter and Rorschach Shock
I have been having this running daydream for several weeks now and thought it might be of interest in case any of you have the same concerns:
It seems a warfighter, freshly returned from theater, service and rank independent, has concerns that drove him/her to seek the help and advice of a psychologist; again service affiliation and gender agnostic because his/her worries should concern all warfighters and those of us that support them. Male pronoun used for ease of reading, and besides according to DoD policy women aren’t supposed to be in combat. If you believe that, I have a bridge for sale!
WF= Warfighter and DR=Psychologist
Setting: Our warfighter has arrived for his appointment with a military psychologist. He is wearing civilian clothes and he is hoping that no one recognized him when he entered the doctor’s office.
WF: (Thinking to himself) What the heck am I doing here? Why do I think this
psychologist can help me? I hope nobody saw me come in. Boy, if the guys in my unit could see me now they would think I really am crazy. I hope it’s not true what they say about warfighters that seek the help of shrinks. I sure don’t need any negative impacts on my career. That reminds me, I have to make doubly sure that our conversation is covered under doctor/patient privilege. Maybe I should just leave…maybe this was not such a good idea.
Scene: Turning to leave, our warfighter runs right into the psychologist!
DR: Pardon me. Let me introduce myself. I am Dr. Rorschach. Are you XXXX?
WF: That’s right, doc, and I am here for my 1000 hours appointment. Thanks for agreeing to see me on such short notice; and it’s nice to meet you, I guess.
DR: Great, you are right on time! I appreciate punctuality, it’s a German trait, I think. Please come right into my office and make yourself comfortable. Is this the first time you have ever visited a psychologist or psychiatrist?
WF: You bet it is doc, shrinks aren’t exactly high on our wish lists in the military and frankly I am surprised at myself for even keeping the appointment, but I am concerned about some things and I hope you can help. Our conversations are confidential, right?
DR: Yes, don’t worry; they are covered by doctor/patient confidentiality as long as I don’t perceive that you pose a serious threat to yourself or to the safety of someone else, except for enemy combatants of course… That’s a joke. Oh well. Then I am forced to notify the authorities.
WF: OK, and don’t worry, doc, it’s not that kind of a problem.
DR: Ja gut! I have your record here and I don’t see any evidence of disciplinary problems, so what can I help you with today? What seems to be the problem?
WF: Well, I’m not really sure. I just seem to be disoriented lately and I have this vague unease about my destiny…you know, my final destination. I have tried to work it out myself, but I have some problems reconciling my sense of duty and my own solution to the problem. I feel kind of guilty sometimes.
DR: When exactly did these feelings start?
WF: During my first deployment to theater, and I have a total of four tours in country. I just returned a few days ago. I am heading out for some R&R tomorrow morning, but wanted to get this concern off my chest first, Doc.
DR: OK, can you be a little more specific about your disorientation and why you feel guilty about your solution?
WF: Doc, have you ever been to the theater, the AOR?
DR: No, I can’t say that I have had that pleasure. (laughs uneasily)
WF: Well Doc, it’s this way. No matter whether it’s high mountain passes that block out the sun or vast expanses of desert that seem endless and that all look the same, it is easy to become disoriented and lose your way over there. When you lead men as I do, it is just not de rigueur to get lost…people get hurt that way. And in a way that’s part of what’s bothering me. I can’t afford to get lost and be responsible for someone being seriously injured or worse because of my lack of ability or expertise, or because I can’t figure out how to work a difficult piece of equipment.
DR: Naturlich, aber doesn’t the military issue you devices to keep you oriented and to prevent you from getting lost? It’s called GPS, I think, and if your equipment works anything like the one in my Mercedes, it is a cinch to use. Don’t you have one of those devices, what’s it called?
WF: Well, that’s the problem, Doc. It called a DAGR and it stands for (expletive deleted) darn antiquated GPS receiver, only it doesn’t.
DR: Doesn’t what?
WF: Doesn’t work worth a (expletive deleted) darn and yet that is what the government has issued me to lead my men with.
DR: So how does that make you feel?
WF: Frustrated! That’s why I’m here.
DR: There must be something I don’t quite understand. I really need to more fully understand your problem. Why would the government issue you something that doesn’t work? That doesn’t make sense to me. Especially something as important as your primary navigation device. You know I can’t find anything without the GPS in my Mercedes. I depend on it all the time. In fact I don’t know how I ever got along without it. It makes driving so much more pleasurable. That big, bright color screen — I just follow the voice commands. It may surprise you and please don’t tell anyone, but I have a female British voice on mine. I think her voice is sexy. What voice do you prefer?
WF: You don’t get it Doc, there is no voice on my DAGR and the screen is black and white and there are not any interactive maps; virtually no situational awareness. It’s very frustrating.
DR: No color screen, no maps, no British female voice. What kind of GPS is that? I have never heard of such a thing. How old is this DAGR thing anyway?
WF: Well Doc as I understand it, the unit was originally designed in about 1995 and there have been virtually no major changes since the initial design.
DR: Ja, so you’re telling me that you are leading men through the mountains and around an inhospitable desert with a piece of equipment designed 14 years ago. That’s simply unbelievable. Are you sure? I mean I am driving around in my Mercedes with the latest in GPS technology, and all I have to worry about is other drivers, although that is sometimes very worrisome, but I digress, and you are risking your life and the lives of your men with antiquated 14-year-old technology?
WF: You got it, Doc. Now you are starting to see the problem from my point of view. The DAGR is so bad that I don’t use it as a handheld device. Instead I went out and spent my own money on a civilian unit, very similar to what you have in your Mercedes, and with automatic map updates every day. So my unit has maps that are actually more current than the military unit. No surprise there. My screen is in color and I have an option for that female British voice to guide me and I can even put in street names and place names to navigate to, unlike the DAGR.
DR: Wait a minute, now I really don’t understand. If you can’t put street names or place names in your DAGR, then how do you navigate?
WF: Doc, with the DAGR you have to use geographical coordinates which we get from a map of dubious origin, and we have to take those coordinates and fat finger them into the device. But that’s not the worst of it. Once you have the waypoints in the DAGR it only gives you, as the crow flies, times and distances; it does not take into account any terrain features, roads, or obstructions, like mountains or lakes. So the distances and ETA’s are always wrong. It’s really very frustrating.
DR: This device really sounds primitive. Why does the military want you to use it?
WF: Doc, it is the Program of Record and the approved government device, and when you use it hooked to or embedded with other equipment it really works well, but as a handheld personal navigation device it really sucks. But then I’m sure you don’t have to worry about things like that in the hospital. I mean you guys always have the most up-to-date equipment, right. Just like your Mercedes.
DR: Ach Du Leber! Not exactly, but when there is better equipment, we try to get it, or send our patients to a nearby civilian facility that has all the modern diagnostic equipment. It’s too bad you can’t do that out in the field with your GPS.
WF: But you see Doc, that’s exactly the problem. As I said, I bought a civilian GPS unit, two of them actually, and that’s what I depend on day-to-day to navigate in country. The problem is they are not approved by the DoD and I’m afraid that if something happens, it will be my neck on the chopping block. Although in many cases the government is actually paying for the civilian units.
DR: So you are the only one that has bought a civilian GPS unit?
WF: (laughing) Not by a long shot Doc. We all have them. None of us use the DAGR as a handheld device when we are dismounted. It can be dangerous to use that thing. It takes forever to get a fix when you first turn it on, something called TTFF or time to first fix, and the accuracy is no better than our commercial or civilian units that give you a fix in about 30 seconds. Gee, even my Apple iPhone gives me a fix in about four seconds and the satellite overhead maps are far superior to anything on the DAGR and of course they are in color. Did I mention the DAGR has a black and white screen?
DR: Again, this doesn’t make sense. Why would the government insist you use an old piece of equipment that is so inferior to what is available on the commercial market?
WF: It’s primarily because the military unit has the ability to receive another encrypted frequency when it is “keyed” and supposedly be a little more accurate and the “keyed” DAGR is supposed to be spoof proof.
DR: You mean when you key, whatever that means, this device it becomes classified? And then you have to carry it around a war zone. And what is spoof proof anyway?
WF: You see, the device that keys the DAGR contains classified information, and after the DAGR is keyed we have to protect it at a higher level of security than if it was not keyed. The keying keeps the enemy from intercepting the GPS signal, messing with it, and then sending it on, which can cause our units to tell us we are someplace we are not. Alt least that’s what I was told.
DR: Has this ever happened, this spoofing thing? And what does this DAGR thing cost anyway? It sounds expensive, but at least it’s big, bulky, and obsolete (laughs).
WF: It’s not funny, Doc, and no, I have never heard of an actual spoofing incident. I read an article about it being accomplished by some scientist and engineers at Cornell University, but the spoofing unit had to be within six inches of the unit being spoofed, and then it could only spoof one unit at a time. And Doc, the DAGR cost between $1700-2000. The worst part about that is, if we loose it or damage it, we are responsible for it and have to pay for it. Consequently most handheld DAGR units go into the footlocker the minute they are issued and they never see the light of day. You would think the DoD would wonder why all the units look brand new when they are returned. They have never been used and probably never will be.
DR: It sounds to me like you have found the solution. Lock the unit away and use a commercial or civilian unit. If lives depend on it, and they do, at least use something that works. Ja, problem solved, yes?
WF: But Doc I have this guilt complex. I have always followed the rules and regulations and now those rules, as dumb as they are, put me and my men in jeopardy. So I did just what you just suggested and now we are all using commercial or civilian GPS units. The problem is it is against DoD regulations, unless you get a waiver, and who knows how that works? I certainly don’t. What do I do and what do I tell my men? They look up to me and expect me to do the right thing.
DR: I can’t tell you to break the rules or disobey DoD regulations, but I can tell you that your first responsibility is to your men and safeguarding their lives. You are not going to be an effective leader if you are anxious and worrying about this DAGR thing all the time. My advice would be to use the best equipment you have available. Equipment that will ensure you know where you are and where you are going. You can’t afford to get lost and put you and your men in a life-threatening situation. I seem to remember that happened to a young soldier early in the war named Jessica Lynch. Just use your best judgment and keep you and your men safe. And it might help to find out more about that waiver thing.
WF: Thanks Doc, I know you’re right, but I’m still a little anxious about it. You know, it’s keeping me up at night and I even have dreams about it.
DR: Ach! Wahoo! Freud in Himmel! Now we are talking. You know dreams tell us a lot about ourselves. What was your relationship like with your father? No, first please take a look at these inkblots and tell me what you see!
WF: Doc, look, I really appreciate all your help, but can we save those inkblots until next time? I really have to go. And I think our time is up.
DR: OK, Ja! Gut! And next time I will show you my Mercedes GPS, Ja?
Until next time, happy navigating and aufwiederzehn.
Don
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