Question about satellites

[Mohoender]

You say that like it is a bad thing!

And I deny any rumors that I am a killer GM!

No I only say it from pure pride. I even managed to kill half a group of player while playing Starwars. They died as they blown up half a city.

During another game, a group of my players managed to flunk their last mission, giving ultimate victory to the Empire remnants.

And I'm the kindest of our small group of GM.

[Legbreaker]

With this kind of coverage, it's very possible that GPS (or it's equivalents) could still be operating in the Cannon Twilight 2000 timeline.

Not a chance I'm afraid.
The GPS satellites require almost constant updating of their internal clocks due to "time dilation". Basically time runs slower in space than it does here on earth (yes, this has been scientifically proven believe it or not), and without the ground stations updating them at least daily, they rapidly become totally useless as navigation markers.

http://en.wikipedia.org/wiki/Spacetime

The difference may only be tiny fractions of a second but that can translate to tens, even hundreds of metres of error accumulating daily without the ground station updates.
Spread that over a year to say mid to late 1998 and GPS might tell you what town you're near, but don't even think about trying to do anything that requires precision such as calling artillery.
Then there's the small issue of needing at least three satellites for a decent fix. With each satellite out of whack so to speak, errors could be compounded even more. Also given that many may well have been knocked out during the war for a variety of reasons, and that they only work when in line of sight, you might get only a few minutes every day of enough satellites over your head.

[Mohoender]

Since Einstein, I have no problem to believe it.

[atiff]

The difference may only be tiny fractions of a second but that can translate to tens, even hundreds of metres of error accumulating daily without the ground station updates.

For reference:
"One of the most significant error sources is the GPS receiver's clock. Because of the very large value of the speed of light, c, the estimated distances from the GPS receiver to the satellites, the pseudoranges, are very sensitive to errors in the GPS receiver clock; for example an error of one microsecond (0.000 001 second) corresponds to an error of 300 metres (980 ft)."

http://en.wikipedia.org/wiki/Gps#Correcting_a_GPS_receiver.27s_clock

[Legbreaker]

It appears that GPS error is approximately 7 metres per 12 hours, or about five kilometres per year if uncorrected. With the unlikelyhood of corrections being implemented since November 1997, by mid 2000, the GPS system (even if satellites still existed) would be out by over ten miles. On the modern battlefield, even in today's civilian world, that sort of error renders GPS totally useless for navigation, let alone plotting artillery, etc.

http://en.wikipedia.org/wiki/Time_dilation#Velocity_and_gravitational_time_dilation_combined-effect_tests

Conventional navigation with map and compass, or even by the stars, is realistically the only way to go in T2k, even in flat featureless terrain such as the desert.

[Targan]

Conventional navigation with map and compass, or even by the stars, is realistically the only way to go in T2k, even in flat featureless terrain such as the desert.

For applications such as navigation at sea accurate time keeping is essential (for longitude anyway, latitude is easier to determine). Luckily things never got so out of hand in the T2K universe that people forgot the date, so assuming you can source almanacs listing the future sunrise and sunsets for given locations on given dates you can reset timepieces to have accurate time.

[natehale1971]

The reason i was talking a bout the GPS sats possibliy being still up there... wasn't about the GPS being used for navigation purposes... but communications. I am wondering couldn't the surviving sats be used for communications

[ArmySGT.]

If you want to.

Using the Manual you can set the time yourself in a PLGR.

[Legbreaker]

IF you know where to point your dish...
AND have the current access codes...

It's really nowhere near as straight forward as it might seem on paper. Without some seriously good maths involved, and the tech to back it up, it's just not worth the effort.

And all that presumes the satellites are still up and functioning.

As for communication, the code/protocol issue is the same. Without the ability to access what is essentially a secure system, and a lot of luck given the complete lack of maintenance of the system since late 1997, using them for communication is a lost cause.

It may seem easy enough to do today, but that's because it's 2011 and we've got MASSES of technology working to make the job easier that most of us aren't even aware off. Wind the clock back 15 years or so and it was a different situation. Then apply bucketloads of war damage to the system and you're looking at the same level of capability which was available around 1970 (at best).

[Mohoender]

For applications such as navigation at sea accurate time keeping is essential (for longitude anyway, latitude is easier to determine). Luckily things never got so out of hand in the T2K universe that people forgot the date, so assuming you can source almanacs listing the future sunrise and sunsets for given locations on given dates you can reset timepieces to have accurate time.

Time determination shouldn't be that much of a problem IMO. I still have a fair amount of mechanical watches around and I'm sure many people do. I bet, that in T2K having or finding one will be a major issue for those wanting to get home.

Then, within each thinking group you would find a navigator (including on land) whose task would be to find his way around using compas, keeping track of time and day and eventually using a sextant (To note, I just read that astronauts had used instruments based on the same principles).

If a group doesn't have a navigator, it should think about finding or forming one. Then, eventual inacuracies or mistakes might lead to very interesting games. Moreover, protecting a good navigator might become a game in the game.

[Targan]

Time determination shouldn't be that much of a problem IMO. I still have a fair amount of mechanical watches around and I'm sure many people do. I bet, that in T2K having or finding one will be a major issue for those wanting to get home.

Then, within each thinking group you would find a navigator (including on land) whose task would be to find his way around using compas, keeping track of time and day and eventually using a sextant (To note, I just read that astronauts had used instruments based on the same principles).

If a group doesn't have a navigator, it should to think about finding or forming one. Then, eventual inacuracies or mistakes might lead to very interesting games.

Very true. The reason I mentioned navigation at sea requiring accurate time keeping is that on land you can use combinations of navigational techniques, including dead reckinging and the use of fixed landmarks, to correct any navigational errors. At sea, in the absence of any landmarks, accurate navigational techniques using chronometers and sextants becomes essential.

Navigation is one of my stronger skills. Spent quite a bit of time at sea as a child. Blitzed navigation during basic training.

[Mohoender]

Navigation is one of my stronger skills. Spent quite a bit of time at sea as a child. Blitzed navigation during basic training.

I'm quite good on land but absolutely not at sea or in the air. Have a character with your skils in a players group and my character would be willing to die in order to save your butt at all costs.

[Mohoender]

Targ

Given what you just pointed out, I realise that the navigation skill is fairly innacurate. It should be completed by two sub-skils : land navigation and spacial navigation (concerning air, sea and space) with the second sub skill being independent and unavailable unless developped in way or another.

[Targan]

That's kind of you to say Mo but if we were at sea and there was anyone available who'd successfully used a sextant in the last 15 years they should be your first choice. I'm waaay out of practice.

In terms of splitting navigation into sub-skills, my playing group is way ahead of you. Navigation skill in Gunmaster has multiple sub-skills. Survival skill can also be used for land navigation but only in terms of basic pathfinding, it is not the primary skill you'd uuse if using a map and compass.