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Geosynchronous GPS?
"Ultimate Buu" writes:
Wouldn't it be prudent for the U.S. to develop a GPS-like system which is based in a geosynchronous orbit, as both the Chinese and Russians are developing ASW (anti-satellite warfare) systems? At the very least such a system should be used as a backup since most precision weapons rely on GPS. It would be much harder for the Chinese to knock out a geosynchronous satellite and it would be almost impossible to do so using lasers (their preferred method at this time). Were you under the impression that GPS was in LEO? GPS is not in GEO, because it doesn't need that specific orbit and because that's a crowded bit of real estate and frequency space as is, but it is in a very high sub-GEO orbit not likely to be reached by first-generation antisatellite weapons. And anything that *can* reach GPS, can almost certainly reach GEO as well. -- *John Schilling * "Anything worth doing, * *Member:AIAA,NRA,ACLU,SAS,LP * is worth doing for money" * *Chief Scientist & General Partner * -13th Rule of Acquisition * *White Elephant Research, LLC * "There is no substitute * * for success" * *661-951-9107 or 661-275-6795 * -58th Rule of Acquisition * |
#2
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Geosynchronous GPS?
difficult to get service at high latitudes.
"Ultimate Buu" wrote in message ... Wouldn't it be prudent for the U.S. to develop a GPS-like system which is based in a geosynchronous orbit, as both the Chinese and Russians are developing ASW (anti-satellite warfare) systems? At the very least such a system should be used as a backup since most precision weapons rely on GPS. It would be much harder for the Chinese to knock out a geosynchronous satellite and it would be almost impossible to do so using lasers (their preferred method at this time). |
#3
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Geosynchronous GPS?
Ultimate Buu wrote:
Wouldn't it be prudent for the U.S. to develop a GPS-like system which is based in a geosynchronous orbit, as both the Chinese and Russians are developing ASW (anti-satellite warfare) systems? At the very least such a system should be used as a backup since most precision weapons rely on GPS. It would be much harder for the Chinese to knock out a geosynchronous satellite and it would be almost impossible to do so using lasers (their preferred method at this time). Sounds like this would merely lead to development of better sattelite knockout weapons... This planet definately doesn't need yet another dumb arms race. -- Sander +++ Out of cheese error +++ |
#4
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Geosynchronous GPS?
On Mon, 4 Aug 2003 11:05:23 +0200, "Ultimate Buu"
wrote: Wouldn't it be prudent for the U.S. to develop a GPS-like system which is based in a geosynchronous orbit, as both the Chinese and Russians are developing ASW (anti-satellite warfare) systems? At the very least such a system should be used as a backup since most precision weapons rely on GPS. It would be much harder for the Chinese to knock out a geosynchronous satellite and it would be almost impossible to do so using lasers (their preferred method at this time). The GPS constellation is at about 12,000 miles altitude... half-way to GEO. They're not going to get much safer than where they are now. Brian |
#5
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Geosynchronous GPS?
On Mon, 4 Aug 2003 11:05:23 +0200, "Ultimate Buu"
wrote: Wouldn't it be prudent for the U.S. to develop a GPS-like system which is based in a geosynchronous orbit, I assume you meant "geosynchronous" in contrast to "geostationary," i.e. a 24-hour orbit vs. a circular 24-hour orbit over the Equator. You might have trouble with the geometry if all the GPS sats orbited in a single plane; I think that a lot of the positions indicated would be ambiguous. The GPS sats will have to be in highly-inclined orbits. Also, geostationary orbit has always seemed to me to be exceptionally vulnerable. Just put a couple of kilos of gravel in the same orbit but going the other way, and pretty soon no comsats. Bob Munck |
#6
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Geosynchronous GPS?
John Schilling wrote:
"Ultimate Buu" writes: Wouldn't it be prudent for the U.S. to develop a GPS-like system which is based in a geosynchronous orbit, as both the Chinese and Russians are developing ASW (anti-satellite warfare) systems? At the very least such a system should be used as a backup since most precision weapons rely on GPS. It would be much harder for the Chinese to knock out a geosynchronous satellite and it would be almost impossible to do so using lasers (their preferred method at this time). Were you under the impression that GPS was in LEO? GPS is not in GEO, because it doesn't need that specific orbit and because that's a crowded bit of real estate and frequency space as is, but it is in a very high sub-GEO orbit not likely to be reached by first-generation antisatellite weapons. And anything that *can* reach GPS, can almost certainly reach GEO as well. It is crowded and they would rather not have a lot of non-planar satellites wandering around. They would rather distribute them around so as to lessen the Geometric Dilution of Precision. |
#7
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Geosynchronous GPS?
On Thu, 07 Aug 2003 15:20:08 -0400, Robert Munck wrote:
Also, geostationary orbit has always seemed to me to be exceptionally vulnerable. Just put a couple of kilos of gravel in the same orbit but going the other way, and pretty soon no comsats. You'd have to be mighty lucky to hit even one comsat by doing that. They aren't exactly strung out on a wire. A comsat doing good station keeping could be anywhere in a cubic mile volume around the ideal GSO track. Those who are in fuel conservation mode describe daily figure 8s which cover a much larger span (roughly +/- 400 miles North South). Meanwhile, a comsat only presents a few square meters of cross section along the orbital track. Even a couple of kilos of fine sand would have a hard time providing a dense enough pattern to have more than an infinitesimal chance of hitting one in a year. Gary |
#8
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Geosynchronous GPS?
"Ultimate Buu" wrote in message .. .
Wouldn't it be prudent for the U.S. to develop a GPS-like system which is based in a geosynchronous orbit, as both the Chinese and Russians are developing ASW (anti-satellite warfare) systems? At the very least such a system should be used as a backup since most precision weapons rely on GPS. It would be much harder for the Chinese to knock out a geosynchronous satellite and it would be almost impossible to do so using lasers (their preferred method at this time). As mentioned, there half way to GEO (energetically, almost all the way there). Another defence would be to have secret, dormant GPS satellites (in a stealth shroud?) which would activate if other ones were knocked out. I wonder if they have that already? |
#9
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Geosynchronous GPS?
On Mon, 11 Aug 2003 04:50:49 -0400, Gary R Coffman
wrote: ... Just put a couple of kilos of gravel in the same orbit but going the other way, and pretty soon no comsats. You'd have to be mighty lucky to hit even one comsat by doing that. ... A comsat doing good station keeping could be anywhere in a cubic mile volume around the ideal GSO track. ... a comsat only presents a few square meters of cross section along the orbital track. Not by my figures. If there are only 1,000 pieces of gravel and a given comsat takes up 1/1,000,000th of the (one-mile cross- section of the) orbital track, you've about one chance in 1,000 of hitting it. But the gravel is moving through the entire GSO track twice a day (at 6 km/s relative) so it has a good chance of hitting one comsat every day or two and all of them within a year or two. I think the probabilities are actually higher than that. Bob Munck |
#10
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Geosynchronous GPS?
On Wed, 13 Aug 2003 15:48:46 -0400, Robert Munck wrote:
On Mon, 11 Aug 2003 04:50:49 -0400, Gary R Coffman wrote: ... Just put a couple of kilos of gravel in the same orbit but going the other way, and pretty soon no comsats. You'd have to be mighty lucky to hit even one comsat by doing that. ... A comsat doing good station keeping could be anywhere in a cubic mile volume around the ideal GSO track. ... a comsat only presents a few square meters of cross section along the orbital track. Not by my figures. If there are only 1,000 pieces of gravel and a given comsat takes up 1/1,000,000th of the (one-mile cross- section of the) orbital track, you've about one chance in 1,000 of hitting it. You're implicitly assuming that the gravel is randomly distributed. But the gravel is moving through the entire GSO track twice a day (at 6 km/s relative) so it has a good chance of hitting one comsat every day or two and all of them within a year or two. You're implicity assuming the gravel randomly changes squares each orbit. Neither of those assumptions can be taken as a given. Gary |
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