Astroidic Ships

[Malenfant]

</font><blockquote>quote:</font><hr />
I think you can actually get a direction just from measuring the very very small time difference between events on different sides of a single detector today. You don't need to space things that widely apart.

Not in most cases as most events are emissions from the stations receiving rebounds of its Emissions.
</font>[/QUOTE]Um, you realise we're talking about neutrinos here. They don't "rebound" off anything. I'm talking about being able to figure out direction from the difference between events in a rather large neutrino detection tank, which I think has been done.

 

[aramis]

The reason for separation is to get more than 1 sec of arc difference; at that range, most computers can get a fix based upon two directional lines and find te point source.

With a directional (azimuth and elev) sensor that provides magnitudes, you only need 2 separate fixes to determine range and location.

With magnitudes only, you need no more than 4; a triangle on a plane, and one above plane. With this you can do the trig to find the point source.

Current S&R using ELT fixes is usually done by using a two-dimentional DF reciever, man portable (L-Per). Two fixes from a distance of a mile apart will provide a good bearing plot on anything within 3-4 miles; you don't even need the magnitude reading for determining distance. (Although, if the ELT is at full charge, it's usually indicative.) The L-Per I used as a cadet in the late 80's weighed less than 2KG, used a dual antenna with a fixed 2ft separation. In a few odd drills, we turned it sideways to gain an elevation fix. (In one, it was sitting on top of a building).

Neutrino sensors are directional, in that the smashed particle goes in the direction smashed, and triggers a descending luminesscence trail away from source. (The exact internals of HOW it luminesces are immaterial for the most part; it is enough to know that it does.)

A few hundred meters separation (easily done on a battleship) gives reliable fixes for a goodly distance.

 

[SlightlyLyons]

Originally posted by Aramis:

In short, they are great because they can tell you the magnitude and type of reaction. They suck because they rely upon unobtanium solutions.

We're talking about thousands of years time here, much less then one thousand years ago landing a man on the moon was considered Imposable. As long as it doesn't violate any laws of physics Unobtanium is good enough for me.

 

[Malenfant]

Originally posted by Aramis:

In short, they are great because they can tell you the magnitude and type of reaction. They suck because they rely upon unobtanium solutions.

Maybe, but we know how Traveller tech works (thanks to FF&S), and we have a pretty decent understanding of how strong, weak and electromagnetic forces work at least (and we can armwave more about gravity). If you look at the nuclear damper, and realise just how damn useful the capability to control strong and weak forces is, then you can do all sorts of great things with it. Like explaining small neutrino sensors, for example .

 

[BetterThanLife]

If you are moving and the target is stationary then you need two bearings, And they can be seperated in time so you only need one sensor. If you are both moving then three is your best bet. Now if your computer is fast enough. The angle doesn't have to be that great. In theory, with accurate enough sensors if the angle is 100th of a second of arc it is enough to determine the target. YOu could in theory get three readings in less than a second. That would give you a good tight triangle to locate the target in. Of course these are lightspeed sensors so at greater distances that causes other problems.

MAtter of fact since most sensors are lightspeed sensors, how do you use point defense against a laser?

And remember that even though hightech, high grade passive sensors can be used at 2 parsecs remember the information from 2 parsecs away is 6.5 years old.

 

[Malenfant]

And remember that even though hightech, high grade passive sensors can be used at 2 parsecs remember the information from 2 parsecs away is 6.5 years old.

That timelag generally doesn't matter for astronomical/astrographic mapping purposes though, which I presume is what such sensors would be used for. Obviously they're going to be useless for spotting ships though.