Navigation is Space

[eroberts]

When at sea, a captain can order a vessel to take a course by referring to directions such as north, east, south, or west. Or he can be more precise by giving a bearing based on North as 0/360<br /><br />How would this work in space? How would some one report the course of another vessel? what land marks would space-crewmen rely on?

 

[kane007]

Pulsars and Galactic Centre.

 

[Aetius]

Real spacecraft use navigation cameras and sun sensors, along with measurements of radio signals from Earth.

 

[yevaud]

If not using the method Aetius mentions, one can describe a moving craft in relation to the plane of the solar system; if it's moving spinwards or anti-spinwards; towards or away from the primary; in reference to a known bodys (e.g. where it is relational to the nearest two planetary orbits). There are numerous methods one can use.<br /><br />Hell, accurately identify three known stars and your relation to them, and you pretty much have it. <div class="Discussion_UserSignature"> <p><em>Differential Diagnosis:  </em>"<strong><em>I am both amused and annoyed that you think I should be less stubborn than you are</em></strong>."<br /> </p> </div>

 

[pyoko]

OK, pointing it in the right direction seems very easy. What about distance travelled? Stars aren't going to move by a detectable degree. Planets move around annoyingly. Radio signal shift or something? Size of the visible Earth? <div class="Discussion_UserSignature"> <p> </p><p> </p><p><span style="color:#ff9900" class="Apple-style-span">-pyoko</span> <span style="color:#333333" class="Apple-style-span">the</span> <span style="color:#339966" class="Apple-style-span">duck </span></p><p><span style="color:#339966" class="Apple-style-span"><span style="color:#808080;font-style:italic" class="Apple-style-span">It is by will alone I set my mind in motion.</span></span></p> </div>

 

[Kalstang]

pyoko: <font color="yellow">What about distance travelled?</font><br /><br />Velocity/speed. If your car is moveing at 60 miles an hour then that is telling you that you can travel 60 miles in one hour. (provided you are able to keep at the same speed constantly throughout those 60 miles.) <div class="Discussion_UserSignature"> <font color="#ffff00"><p><font color="#3366ff">I have an answer for everything...you may not like the answer or it may not satisfy your curiosity..but it will still be an answer.</font> <br /><font color="#ff0000">"Imagination is more important then Knowledge" ~Albert Einstien~</font> <br /><font color="#cc99ff">Guns dont kill people. People kill people</font>.</p></font><p><font color="#ff6600">Solar System</font></p> </div>

 

[Mee_n_Mac]

Let me ask pyoko's next question : How do you measure velocity ? <br /><br />Well one way is to measure acceleration (which you can do with onboard instruments) and then integrate that to get velocity which integrated again gets you distance traveled. But errors can creep into this which is one reason why we have GPS rather than rely on inertial navigation systems (which when good aren't cheap). You can measure speed relative to some object using the Doppler shift but you've got time delays in getting the signal back (unless you've set up some beacons) and even then you've only got speed along the line of sight to that object ... so you need multiple objects to get a 3D velocity. Measuring the redshift of various stars and comparing to a known table could also do it (in theory) though I don't know if equipment in a spaceship could be accurate enough for the relatively low velocities. Now we need an astronomer type person to answer that question. Maybe one will meander by .... <img src="/images/icons/smile.gif" /> <div class="Discussion_UserSignature"> <p>-----------------------------------------------------</p><p><font color="#ff0000">Ask not what your Forum Software can do do on you,</font></p><p><font color="#ff0000">Ask it to, please for the love of all that's Holy, <strong>STOP</strong> !</font></p> </div>

 

[hracctsold]

If you would look in a copy of the ST, nx gen Technical Manual or is it the ST Compendium, there is a detailed section on how to determine the direction travel from where they are at the time. (Or some such nonsence stuff as that). <br /><br />I was just quickly looking for it, but could not locate it, but do remember reading how they determined how to tell what direction to take by the quad. they gave. <br /><br />And it really could not be the compendium because that just listed the shows of the original one, FYI.

 

[etavaunt]

I think any attempt to use trig to calculate your speed/velocity/position from readings taken of STARS apparent angular displacement as you travel, from a moving vessel that would obviously have fuel/people/air etc all moving about in it, is doomed to failure/highly likely to be inaccurate.<br /><br />I know in planes,people moving about alter its attitude, so i guess (under thrust) things moivng about the space-ship would also introduce infintesimal small errors in the base line that would be something like a isocoles triangle mutiple lightyears along its long sides, and only fractions of that along its (distance traveled) short edge.<br /><br />I don't say it would be impossible, but I am pretty sure you would need something much more accurate for a manned vessel. Quite happy to have someone prove me wrong here.<br /><br />I think maybe a COLLECTION of the various methods would be needed. Or a continuious reading taken somehow, and the average taken as correct, from a signifigent number of readings.<br /><br />Are they able to fix their position three dimensionally accurately, just from star fixes, enough to work as their base to calculate firing times?.

 

[yevaud]

Yes, as if you know your position in relation to several fixed known objects (as well as where your destination is), you can accurately determine your position, velocity, bearing.<br /><br />Remember, GPS operates along similar lines, that of relating yourself to several known reference points. <div class="Discussion_UserSignature"> <p><em>Differential Diagnosis:  </em>"<strong><em>I am both amused and annoyed that you think I should be less stubborn than you are</em></strong>."<br /> </p> </div>

 

[lsbd]

Interstellar navigation, with present technology, would be a frakin nightmare. How would you plot a course to some distant planet? It would take some heavy duty calculations, because you would need to know where that planet is going to be, not today, but at some time in the future when you plan to arrive. Do we even have enough information to calculate this?

 

[yevaud]

Oh yes, certainly it would take some heavy calculations, and in real time, or nearly so.<br /><br />But as long as you can obtain several known references - planets, stars, pulsars, quasars - you know your position quite well. Velocity can be derived with a bit more work. <br /><br />Frankly, the real danger I've always seen is any vehicle moving at a fairly high velocity will encounter debris. It's going to hit <i>really</i> hard.<br /><br />(We won't even get into the effects at even higher velocities, though I will say that Radiation is not your friend) <div class="Discussion_UserSignature"> <p><em>Differential Diagnosis:  </em>"<strong><em>I am both amused and annoyed that you think I should be less stubborn than you are</em></strong>."<br /> </p> </div>