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Thread: What if: GPS and all Western satellites are successfully neutralised

  1. #46
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    Quote Originally Posted by FJV View Post


    At about 2:30 in the video, think smaller spheres, because UAV's aren't as high up as sattellites. (the video is a bit meh)

    Drawback is you cover a smaller area with UAV's, but you only really need to cover the conflict area instead of the entire world, so that reduces the demand on such a system.
    OK, here's why I think such a system is not quite all that and a bag of chips: How do the UAVs know where they are? I mean, they may well be able to give you a fix, but relative to what? See my point? The UAVs may well tell you where you are relative to them, but where are they relative to the Earth? Moreover, the thing about real satellites is that their orbits are known, consistent, and most importantly constant. In that respect, they replicate for all intents and purposes, any real star that you will find in the Nautical Almanac and your Rude Starfinder.

    The difference between a GPS fix and one attained by celestial navigation is that the GPS fix is really just like a radar fix on an observable landmark. You know that landmark is there; now you just need to know how far you are from it, so you paint it with your radar. If you are really sexy, you zap it with your fire control radar. Do that with four or more such landmarks and you can get a pretty good fix; ditto with satellites. With a celestial fix, and I'm simplifying things here, you are basically using your Dead Reckoning position, which is purely an estimation based on your expected course and speed over ground, to include set and drift caused by current, as a starting point, and then a trigonometric function of the difference between the height computed of a given star for that time of day and your estimated position on the surface of the Earth, and the actual height observed above the horizon (your sextant shot) of the same star. In other words, you are comparing the position of a star above the horizon taken from the Nautical Almanac for 05:32 AM on August 29th for the general vicinity of the Canary Islands, to your actual sighting of that same star, like Betelgeuse or Aldebaran at the same time and estimated place. The time is important. That chronometer better be gnat's ass accurate or else you will end up in East Jesus. If the height observed is greater, you are closer to your DR position. If the height computed is greater, you are farther away from your DR.

    Your fix not being particularly near your DR is not a bad thing. It just means you have to re-calibrate your estimated course, speed, and the set and drift associated with the ocean currents in the area. Once you have a fix, you correct your course and speed if necessary, and start a new track. You get a good fix with five or six observable stars at either twilight or just before dawn when you have a really sharp horizon, you can get a pretty accurate picture of where you are in the greater scheme of things.

    Now, I am assuming that these UAVs might be set up to orbit one or more known landmarks, like a mountain peak, the Eiffel Tower, Old Faithful Geyser, or whatever, so long as it is fixed in space and is not likely to change. If they can maintain their position in an orbit around that known physical landmark, then they might be able to give you their position relative to that landmark, and then your position from the UAV. I threw this graphic below together as an example of how I think it could work. One UAV orbiting Gibraltar, one orbiting the Eiffel Tower, one orbiting Mt. Vesuvius, one orbiting the Great Pyramid at Giza and one orbiting the Hagia Sophia in Istanbul. I have no clue what altitude they'd have to be operating at in order to maintain UHF LOS or whatever, but probably something on the order of angels 70 to 100 I would think. Should be doable regardless as one doesn't have to worry about keeping the SPAM in the can alive. In any event, as I said, the UAV would have to maintain its position relative to that landmark, and then report both its position in terms of both range and bearing, from that landmark, and your straight line distance from the UAV. That just might work.

    Last edited by desertswo; 30 Nov 13, at 01:42.

  2. #47
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    Quote Originally Posted by desertswo View Post
    OK, here's why I think such a system is not quite all that and a bag of chips: How do the UAVs know where they are? I mean, they may well be able to give you a fix, but relative to what? See my point? The UAVs may well tell you where you are relative to them, but where are they relative to the Earth? Moreover, the thing about real satellites is that their orbits are known, consistent, and most importantly constant. In that respect, they replicate for all intents and purposes, any real star that you will find in the Nautical Almanac and your Rude Starfinder.

    The difference between a GPS fix and one attained by celestial navigation is that the GPS fix is really just like a radar fix on an observable landmark. You know that landmark is there; now you just need to know how far you are from it, so you paint it with your radar. If you are really sexy, you zap it with your fire control radar. Do that with four or more such landmarks and you can get a pretty good fix; ditto with satellites. With a celestial fix, and I'm simplifying things here, you are basically using your Dead Reckoning position, which is purely an estimation based on your expected course and speed over ground, to include set and drift caused by current, as a starting point, and then a trigonometric function of the difference between the height computed of a given star for that time of day and your estimated position on the surface of the Earth, and the actual height observed above the horizon (your sextant shot) of the same star. In other words, you are comparing the position of a star above the horizon taken from the Nautical Almanac for 05:32 AM on August 29th for the general vicinity of the Canary Islands, to your actual sighting of that same star, like Betelgeuse or Aldebaran at the same time and estimated place. The time is important. That chronometer better be gnat's ass accurate or else you will end up in East Jesus. If the height observed is greater, you are closer to your DR position. If the height computed is greater, you are farther away from your DR.

    Your fix not being particularly near your DR is not a bad thing. It just means you have to re-calibrate your estimated course, speed, and the set and drift associated with the ocean currents in the area. Once you have a fix, you correct your course and speed if necessary, and start a new track. You get a good fix with five or six observable stars at either twilight or just before dawn when you have a really sharp horizon, you can get a pretty accurate picture of where you are in the greater scheme of things.

    Now, I am assuming that these UAVs might be set up to orbit one or more known landmarks, like a mountain peak, the Eiffel Tower, Old Faithful Geyser, or whatever, so long as it is fixed in space and is not likely to change. If they can maintain their position in an orbit around that known physical landmark, then they might be able to give you their position relative to that landmark, and then your position from the UAV. I threw this graphic below together as an example of how I think it could work. One UAV orbiting Gibraltar, one orbiting the Eiffel Tower, one orbiting Mt. Vesuvius, one orbiting the Great Pyramid at Giza and one orbiting the Hagia Sophia in Istanbul. I have no clue what altitude they'd have to be operating at in order to maintain UHF LOS or whatever, but probably something on the order of angels 70 to 100 I would think. Should be doable regardless as one doesn't have to worry about keeping the SPAM in the can alive. In any event, as I said, the UAV would have to maintain its position relative to that landmark, and then report both its position in terms of both range and bearing, from that landmark, and your straight line distance from the UAV. That just might work.
    [/IMG]
    I haven't watched FJV's video, but your explanation makes a lot of sense. But I think having a UAV orbiting a landmark defeats the purpose in this scenario. A fixed orbit around a known location means that the enemy knows where to look for your UAV, just like he did with your satellite.

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    I thought that having three locations was enough to fix your location. Why the extra need for two or three more locations?

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    Quote Originally Posted by cataphract View Post
    I haven't watched FJV's video, but your explanation makes a lot of sense. But I think having a UAV orbiting a landmark defeats the purpose in this scenario. A fixed orbit around a known location means that the enemy knows where to look for your UAV, just like he did with your satellite.
    Yes but it is easier to replace a lost UAV than a lost satellite and is vastly cheaper and easier to do.

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    Quote Originally Posted by cataphract View Post
    I haven't watched FJV's video, but your explanation makes a lot of sense. But I think having a UAV orbiting a landmark defeats the purpose in this scenario. A fixed orbit around a known location means that the enemy knows where to look for your UAV, just like he did with your satellite.
    One more time; how does the drone know where it is? If there is no satellite constellation for it to guide off of, then your next options are a celestial fix, which is doable, but not generally accurate enough for something as sophisticated as a launch box for a Tomahawk strike, or physical landmarks. Those would be the most accurate for a couple of reasons, not the least of which is that they are close relatively speaking, and can be seen by radar in all weathers. Stars cannot; a point that others have made. Meanwhile, Mt. Vesuvius will be there a long, long time, yes?

    As Blademaster has indicated, UAVs are cheap. Keep throwing them up there until you eliminate whatever is a threat to them. Then you eliminate whatever sent the threat up there in the first place.

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    Quote Originally Posted by Blademaster View Post
    I thought that having three locations was enough to fix your location. Why the extra need for two or three more locations?
    More is better. A typical morning's star sighting will include five to six good observable bodies. The more you can refine your fix, the more accurate it will be. We also shoot multiple land marks when doing visual or radar navigation while entering or leaving port. I don't believe I've ever shot less than five. You play fast and loose with that sort of stuff and go aground, some really mean old men will take away your birthday.

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    Quote Originally Posted by cataphract View Post
    But I think having a UAV orbiting a landmark defeats the purpose in this scenario. A fixed orbit around a known location means that the enemy knows where to look for your UAV, just like he did with your satellite.

    without going into detail....

    the landmark is a point in time

    the landmark can also be virtual - it can be a random geolocation that makes no sense to a human or an analyst but is a waypoint or marker as big as the eifel tower as far as the UAS control system is concerned

    UAS behaviour is entirely dependent on its mission set

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    As long as the UAV can receive 3 ground stations, the position of the UAV can be triangulated from the ground stations. (it can fly anywhere in such an area)

    You could also triangulate directly from the ground stations, but the UAV's would extend the range.

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    There's an assumption going on in here that UAS are all using satellites to do their shopping - that's not necessarily so.

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    Quote Originally Posted by gf0012-aust View Post
    There's an assumption going on in here that UAS are all using satellites to do their shopping - that's not necessarily so.
    No, it's not. However, that's as far as I'm going with that one.

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    Quote Originally Posted by desertswo View Post
    No, it's not. However, that's as far as I'm going with that one.
    Not referring to you making an assumption...

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    Quote Originally Posted by gf0012-aust View Post
    Not referring to you making an assumption...
    Oh, I know. That wasn't my point. It's just that I know a whole lot more about this stuff than most, as I was on the ground floor of drone technology and its applications in C4ISR. So while I'll offer observations on this or that, I won't go into too many grim details. Like elaborating on your post. Bad juju for all concerned.

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    Quote Originally Posted by desertswo View Post
    Oh, I know. That wasn't my point. It's just that I know a whole lot more about this stuff than most, as I was on the ground floor of drone technology and its applications in C4ISR. So while I'll offer observations on this or that, I won't go into too many grim details. Like elaborating on your post. Bad juju for all concerned.
    ack

    ditto this end on C4ISR

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    "But how often do you practice them [land nav] in the field exercises?"

    I'll have a partial answer in a few weeks. Curious to see how a co-employee, newly-commissioned 2Lt infantry officer, reviews his OBC (or whatever they call it now) experience. Particularly land nav and how it's practically integrated. It's only partial as that's institutional training. What goes on at the troop level is more telling. I know this-I have utter disdain for any soldier above the rank of PFC and any officer regardless of rank who can't land navigate.

    It would be a long, slow slide and enough to stretch the wildest imagination must occur before armies and nations are brought to their knees because of technological over-reliance. You are correct, however, that older technologies might regain some relevance. PADS (Position Azimuth Determination System) might, for instance, make a re-emergence. A cool, HUMVEE mounted gyro-nav system that had to periodically re-orient over a known point and a limited range (about twenty miles max from the orienting station). Still, a quantum leap forward for artillery survey. New and utterly revolutionary in 1985.

    Outmoded by 1991.
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    Quote Originally Posted by S2 View Post
    [B]

    It would be a long, slow slide and enough to stretch the wildest imagination must occur before armies and nations are brought to their knees because of technological over-reliance. You are correct, however, that older technologies might regain some relevance.
    I can't tell whether you are concerned about technological over-reliance bringing down nations or you are not concerned. I see technology replacing human problem solving to the extent that cutting the power could make us virtually helpless. But what I want to understand is the term over-reliance. At what point does it become 'over' versus simply 'reliant"?
    To be Truly ignorant, Man requires an Education - Plato

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