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National Space Policy: NSDD-42 (issued on July 4th, 1982)
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#62
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National Space Policy: NSDD-42 (issued on July 4th, 1982)
In sci.space.policy Scott M. Kozel wrote:
GPS is not "offensive space-based weaponry", and for you to assert that it is, shows you have an agenda to post disinformation about the topic. Fine. And I doubt many people would argue against that. But surely you don't want to claim that specificly military tailored and military controlled navigation satellites used in weapons targeting are part not of space militarisation? -- Sander +++ Out of cheese error +++ |
#63
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GPS Megadeath
Steven James Forsberg wrote:
: The problem with that is... We had no need of such a capability. : What an SSBN needs is a method of knowing it's position *without* : having to surface, or preferably even coming close to the surface. We : already had that capability with SINS, SINS/ESGM, and with ESGN. : From the point of view of an SSBN, GPS is 'nice-to-have', not 'must : have'. I'm not certain I quite agree with that. You may do so. I'll refute as best I can without risking a vacation in Kansas. (Do keep in mind I did this stuff for a living.) The USN definitely needed such a capability. For starters, SSBNs launch from relatively close to the surface, and in launching advertise themselves very well, and are not supposed to be anywhere near an enemy when they do. Thus, coming close to or at the surface is not such a liability. SSBN's launch from considerably beneath periscope depth. Transiting to PD and back to launch depth not only increases the length of the launch process, but increases the 'something is up' signature. We won't launch if we know we are being shadowed, but for obvious reasons we always behave as if we are being shadowed and just don't know it. Thus coming close to the surface does the two things the USN has always avoided (and spent a great deal of money to avoid[1]); increasing the length of the launch sequence and increasing the launch signature. Thus coming to or close to the surface is a liability. [1] For example, modifying the valves used to pressurize the launch tubes in order to reduce the noise they generated. The pressurization and flow control valves in the hovering system were also modified for greater quietness because setting up that system as we made other launch preps was a noisy and very obvious signature. Across the history of the SSBN force reducing the indiscretion rate and reducing the length and signature of the launch process have been right behind accuracy (and not far behind at that) in the goals and requirements of the system. Thus LORAN capability was added to the bouy and wire (discussed below) and the BQS-3 secure fathometer developed to avoid surface exposure. We did/do have mast mounted antenna for Transit/GPS, but these are used as little as possible to avoid going near the surface. This is particularly true if you are going to be using satcomms for any purpose - verification, mission update, etc. We don't, not really. Satcomm is a backup for two other systems, one which allows us to patrol deep (the bouy) and another which allows us to patrol near (but not breaking as satcomm requires) the surface (the wire). Also, SSIXS is a store-and-forward system (which requires interrogation by the SSBN) rather than the continuous comms provided by the systems the surface fleet and the rest of the DoD uses. Secondly, the USN wanted to be able to use SSBN launched missiles in counterfire, not a a countervalue, role. You can nuke a city without too much accuracy, but if you want to plink hardened silos and buried targets accuracy becomes much more important. Certainly accuracy is important, but SSBN/SLBM system design also has to consider issues (outlined above) that an ICBM system does not. That was a prime driver behind the development of the ESGM/ESGN. Not only was it more accurate than SINS, but it also required fewer and less frequent (possibly detectable) external updates to maintain overall system accuracy. D. -- Touch-twice life. Eat. Drink. Laugh. |
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GPS Megadeath
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National Space Policy: NSDD-42 (issued on July 4th, 1982)
Sander Vesik wrote:
Scott M. Kozel wrote: GPS is not "offensive space-based weaponry", and for you to assert that it is, shows you have an agenda to post disinformation about the topic. Fine. And I doubt many people would argue against that. But surely you don't want to claim that specificly military tailored and military controlled navigation satellites used in weapons targeting are part not of space militarisation? I just got done refuting that notion. GPS has many civil uses, and is no more "space militarisation" than is things like computers, calculators, and microelectronics that makes modern satellites feasible, plus weather satellites and other communication satellites. Accurate ICBMs and SLBMs existed by the thousands, on both sides of the Iron Curtain, decades before GPS ever existed. |
#67
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National Space Policy: NSDD-42 (issued on July 4th, 1982)
In sci.space.policy Scott M. Kozel wrote:
Sander Vesik wrote: Scott M. Kozel wrote: GPS is not "offensive space-based weaponry", and for you to assert that it is, shows you have an agenda to post disinformation about the topic. Fine. And I doubt many people would argue against that. But surely you don't want to claim that specificly military tailored and military controlled navigation satellites used in weapons targeting are part not of space militarisation? I just got done refuting that notion. GPS has many civil uses, and is no more "space militarisation" than is things like computers, calculators, and microelectronics that makes modern satellites feasible, plus weather satellites and other communication satellites. This is simply nonsense. When was the last time you saw a receiver on sale that could actually make use of all GPS? GPS is not in any way comparable to computers or modern electronics. It is not even designed for civilian use, you may as well claim military cargo planes are not military aircraft at all. In fact, if you go by US laws, any placement of satellites in orbit at all is space militarisation due to classification of satellites and satellite technology as munitions Accurate ICBMs and SLBMs existed by the thousands, on both sides of the Iron Curtain, decades before GPS ever existed. Which is utterly irrelevant to whetever GPS is space militarisation or not. -- Sander +++ Out of cheese error +++ |
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GPS Megadeath
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#69
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National Space Policy: NSDD-42 (issued on July 4th, 1982)
Sander Vesik wrote:
Scott M. Kozel wrote: Sander Vesik wrote: Scott M. Kozel wrote: GPS is not "offensive space-based weaponry", and for you to assert that it is, shows you have an agenda to post disinformation about the topic. Fine. And I doubt many people would argue against that. But surely you don't want to claim that specificly military tailored and military controlled navigation satellites used in weapons targeting are part not of space militarisation? I just got done refuting that notion. GPS has many civil uses, and is no more "space militarisation" than is things like computers, calculators, and microelectronics that makes modern satellites feasible, plus weather satellites and other communication satellites. This is simply nonsense. When was the last time you saw a receiver on sale that could actually make use of all GPS? GPS is not in any way comparable to computers or modern electronics. It is not even designed for civilian use, you may as well claim military cargo planes are not military aircraft at all. You're the one who is posting nonsense. Obviously you've never seen the commercially available receivers that instantly provide the exact coordinates of a location to within a few feet. That has valuable civil navigational uses. In fact, if you go by US laws, any placement of satellites in orbit at all is space militarisation due to classification of satellites and satellite technology as munitions Complete, utter nonsense. Accurate ICBMs and SLBMs existed by the thousands, on both sides of the Iron Curtain, decades before GPS ever existed. Which is utterly irrelevant to whetever GPS is space militarisation or not. It is totally relevant, since those ICBMs and SLBMs can be (and were) very accurate without GPS. You're just looking for any far-fetched excuse possible to attack the U.S. |
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GPS Megadeath
From Derek Lyons:
(Stuf4) wrote: You could likewise argue that Air Force strategic bombers had no need for GPS because they had INS supplemented with TACAN and RADAR. The behavior of the USAF across it's history supports that argument, they were a latecomer to GPS, not an early adopter. The bombers depended on radar and visual sightings once they entered the bombing run. One suspects their involvement was more attributeable to politics (increasing the accuracy of manned bombers increases their viability, and being involved in a program that was in space but not USAF controlled) as any desire for accuracy. Perhaps I was not clear enough the first time. Derek, GPS was funded because: INS was neither accurate nor reliable. INS may be accurate after being fixed to a known location, but INS *does not measure position*. It does not even measure velocity. It measures acceleration. And that means that the slightest error gets integrated into a larger error in velocity, which gets integrated into an EVEN LARGER error in position. Over short periods of time, INS accelerometers were well known for running the position away with a skewed platform. Bomber missions take several hours and there are long stretches of time between fixes where INS's often behave badly. It took diligence of a highly skilled navigator to keep the INS "corralled", so to speak, by regularly pumping good fixes into the system. ....and *even then* it was known to go inaccurate. Aside from errors within the INS itself, even highly skilled navigators would make errors in identifying radar targets to fix off of (there were lots of other sources of error as well). The optimal solution was to measure position directly, instead of integrating all those errors. The Air Force was in on the *ground floor* for the DNSS (renamed GPS), so I don't know why anyone would say that they were latecomers. The Navy had a 2-D system that worked at extremely low velocity. Jets can't stop like subs can. And jets need 3-D position. It *was* the Air Force who created such a system. The most significant GPS contribution from the Navy was the atomic clocks. The basics of the signal theory came from the Air Force. As derived from MOSAIC, it was the technology that was designed for positioning ICBM launches that gave us the system we use today. Air Force technology. Notice that even today the space shuttle is involved with a GPS upgrade. For every flight to date it had multiple INS with multiple TACAN. If this was deemed reliable and accurate enough then the GPS conversion would be a complete waste of time and money. Now talk to the astronauts and see how badly the want GPS. They want it because it's available. There was certainly no such clamor during the design phase. While the shuttle is capable of doing automatic navigation fixes from TACAN stations, it still suffers the accuracy problems inherent in INS systems that don't get precise position updates. Part of astronaut pilot training is practicing landings with *bad nav*. This is why they want GPS. They don't like the idea of their nav system taking them down to a spot that is so far off the runway that they crash. The primary issue isn't convenience. It isn't technology fashion trends. It's a matter of living, versus not. The reason why there was no "clamor during the design phase" was because there was no GPS when shuttle was designed. It was just a theory. ~ CT |
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