|
|
| Author |
Thread Statistics | Show CCP posts - 0 post(s) |
Xianthar
STK Scientific
The Initiative.
   |
Posted - 2009.02.14 19:44:00 -
[1]
Assuming all fixed points are non co-located and reasonably spaced out around the unknown point
Distance to an unknown point from 1 known location (a probe) will place the unknown spot somewhere in a sphere around that probe with radius = the distance measured.
Distance to an unknown point from 2 known locations will place the unknown location somewhere on the circle than is the intersection of the spheres formed when looking at each probe separately
Distance to an unknown point from 3 known locations will place the unknown location as one of 2 points, the intersection of the spheres formed when looking at each probe separately
Distance to an unknown point from 4 known locations will place the unknown location at precisely 1 possible location.
Nothing is made up here, 4 locations are required to find a point in open 3d space.
Triangulation works on the surface of the earth to find "stuff" because with 3 known distances you get 2 possible locations for the unknown, if the known locations are properly spread out only 1 of those 2 possible points will be on the earths surface, thus you can rule out the other.
More known distances just help to account for inaccuracies in the distance measurement method which there is always some due to various issues. For instance the GPS system has to account for the fact that time travels slower on the earths surface than it does in orbit.
cheers
|
Xianthar
STK Scientific
The Initiative.
|
Posted - 2009.02.14 20:15:00 -
[2]
 Originally by: Hugh Ruka
Originally by: Xianthar
Triangulation works on the surface of the earth to find "stuff" because with 3 known distances you get 2 possible locations for the unknown, if the known locations are properly spread out only 1 of those 2 possible points will be on the earths surface, thus you can rule out the other.
More known distances just help to account for inaccuracies in the distance measurement method which there is always some due to various issues. For instance the GPS system has to account for the fact that time travels slower on the earths surface than it does in orbit.
cheers
triangulation on earth works only on land. since the height is given by the height of the surface, you only need to work 2 dimensions (a plane bent to form a sphere basicaly).
however it would not work underwater or in the air, as it would give an infinitely long line of possible locations :-)
nope, you will not get an infinite line of points, you will get precisely 2 points in any reasonable arrangement, its simply the intersection of 3 spherical shells, which can never result in an infinite line.
cheers
|
Xianthar
STK Scientific
The Initiative.
|
Posted - 2009.02.14 20:32:00 -
[3]
Originally by: Miss Moonwych
Basicly you were/are assuming that the target lies exactly in the A,B,C plane. Which most of the time wont be the case.
M.M.
its also theoretically possible to locate a point with just 2 know distances but the location of the 2 probes and the unknown location would have to be co-linear, the odds of which are really, really bad, still i wonder if CCP implemented it.
cheers
|
Xianthar
STK Scientific
The Initiative.
|
Posted - 2009.02.15 09:00:00 -
[4]
Originally by: Kopkiller
Edit: Did you actually know a GPS knows your altitude?
actually it doesn't, the gps system locates the receiver to a point in space through trilateration (apologies for my improper use of triangulation earlier). you would need to compare this point to a topo map to get your true altitude which is what "good" systems do. alternatively you can make estimates at the location of the surface based on the shape of the earth (which is not a sphere) and thus make a guess at the altitude tho its not nearly as accurate and would be similar to a barometric pressure based altimeter reading.
cheers
|
Xianthar
STK Scientific
The Initiative.
|
Posted - 2009.02.15 09:02:00 -
[5]
Originally by: Jack Jombardo
Only 3 probes needed would be nice.
Had a scan with 7 (!) probes out last night and couldn't get a result better as 81% after nearly full probe-time :(.
this has nothing to do with the number of probes, CCP has now said multiple times that the sensor strength of some sites needs to be rebalenced thus the hard to find sites before, 10/10 plexes for example are currently impossible to find. this will be fixed later.
|
|
|
| |
|