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Results tagged with Search options user 25

Questions regarding the Global Positioning System's satellites and uses.

7
votes
They could not have used it without some serious modifications. Most GPS systems fall under what is known as the "CoCom", which prohibits GPS from working over 60,000 feet or 1200 miles per hour. Thus it could not have functioned without some significant improvements in the firmware. …
answered May 3 '16 by PearsonArtPhoto
4
votes
, but there has been some work to making one. It would be MUCH cheaper, more accurate, and overall just better. GPS satellites are expensive, they are all space rated atomic clocks, some of the most … . The way indoor GPS typically works is by estimating your location from other means, and looking for the very low signal strength signal coming at the right time. …
answered Apr 2 by PearsonArtPhoto
0
votes
GPS receives use the distance between the user and the satellite, not the distance between satellites. In fact, the name for this is trilateration. If time isn't well known, then one can use an …
answered Jan 3 '16 by PearsonArtPhoto
1
vote
The GPS constellation wanted to be high enough where many of them could be seen, but not in Geostationary orbit, because it wasn't needed. Somewhat arbitrarily it was decided to set them up such that … , they wanted a point to start, but not be in exactly the same plane as GPS. The same repeating orbits seemed like a natural boundary point, and 17 was somewhat arbitrarily chosen as a numerator for the …
answered Apr 5 by PearsonArtPhoto
10
votes
The furthest satellite that I have seen use GPS is the AO-40, an amateur built satellite. In fact, they did a research paper on the subject. The paper states that it was able to achieve a navigation … even further, but just to receive the signal beyond the GPS constellation is impressive. It should be stated that this problem is difficult because the GPS antennas are all focused at the Earth, thus …
answered Jul 21 '13 by PearsonArtPhoto
62
votes
GPS isn't affected by demand, as it is transmitting only from satellites, and the receivers only receive, they do no transmit to the satellite at all. At best, there is a slight degradation by having … antennas in really close proximity. A million man march, each with a GPS device, might cause some degradation as each device will absorb a bit of the energy that others might. If it were to happen …
answered Aug 6 '17 by PearsonArtPhoto
25
votes
lower altitude could in theory work as well, but the chosen altitude seems to be a far enough distance to be useful, but not so far as to have communication link issues, etc. The cost to get a GPS … , however, is that you would need more satellites to ensure that the complete coverage had been met. GPS is fundamentally a military system, and it is required not to have gaps on the ground. It …
answered Aug 30 '15 by PearsonArtPhoto
12
votes
tell the clock to jump forward or backward a certain amount of time. For GPS, this update can occur every 8 hours, but in practice is done every 24 hours. The satellites each have onboard atomic … are sent up to the satellite via the GPS ground network. The time standard used for GPS clocks is a whole number of seconds from UTC. GPS time does not account for leap seconds, thus the whole number of seconds time difference. …
answered Mar 7 '16 by PearsonArtPhoto
3
votes
accurate when straight overhead, it could be a refraction or speed of light error. Make sure your GPS location and time are accurate. Try plotting various of your values vs others. Determine the distance … to a known source. I recommend using the Lunar laser reflectors on the moon. With these, you can get great results. If you are able to do this with satellites, consider using one of the GPS
answered Jan 3 '18 by PearsonArtPhoto