Hard Light Productions Forums

Hosted Projects - Standalone => Diaspora => Topic started by: Horizon on October 06, 2012, 02:20:48 pm

Title: DRADIS acronym -
Post by: Horizon on October 06, 2012, 02:20:48 pm
I see people using the long-hand Direction, RAnge and DIStance. 

However, anyone who's used a radar will tell you Range IS Distance.  That's what 'range' means.  Range to target means Distance to it.  So Range and Distance on a radar as separate units of measurement...well, can someone explain what they mean by Range and Distance as two different units?

I always thought DRADIS stood for Directional Radiological Alarm Detection and Identification System.  Makes more sense to me.

What do you guys think?
Title: Re: DRADIS acronym -
Post by: MatthTheGeek on October 06, 2012, 02:24:45 pm
I think it's a radar with coloured blips and stuff. Fancy names are for fancy people. I'm just there kill stuff.
Title: Re: DRADIS acronym -
Post by: The E on October 06, 2012, 02:54:38 pm
I see people using the long-hand Direction, RAnge and DIStance. 

However, anyone who's used a radar will tell you Range IS Distance.  That's what 'range' means.  Range to target means Distance to it.  So Range and Distance on a radar as separate units of measurement...well, can someone explain what they mean by Range and Distance as two different units?

I always thought DRADIS stood for Directional Radiological Alarm Detection and Identification System.  Makes more sense to me.

What do you guys think?

Direction, RAnge, DIStance is canon. Sorry.
Title: Re: DRADIS acronym -
Post by: Swifty on October 06, 2012, 03:14:00 pm
Direction, Range, and Discrimination makes much more sense to me even if it's not canon. A big part of DRADIS' functions is to discriminate different ship classes and their IFF signatures.
Title: Re: DRADIS acronym -
Post by: newman on October 06, 2012, 03:19:29 pm
To play devil's advocate, range and distance don't necessarily have to mean the same thing. Range can mean range of perception - in this case, a spherical area around the ship inside which DRADIS can detect targets. Distance can then signify distance to targets and between them.

A bit of a stretch, I know, but sci-fi fans are used to stretching reality to cover for lazy writers anyway :)
Title: Re: DRADIS acronym -
Post by: General Battuta on October 06, 2012, 03:31:07 pm
I thought Direction, Range, and Displacement was always the most parsimonious.
Title: Re: DRADIS acronym -
Post by: headdie on October 06, 2012, 03:39:05 pm
Quote from: http://en.battlestarwiki.org/wiki/DRADIS
The "Direction, RAnge, and DIStance" breakdown of the acronym "DRADIS" was listed in an early manuscript of the first half of the Miniseries. Since some major elements of this script were changed (such as Kobol being the sole home of the Colonies, and not separate worlds) in comparison to the completed teleplay, canonical use of this breakdown should be taken with some skepticism.

There is some evidence to suggest that the original breakdown is the canonical version. In "Kobol's Last Gleaming, Part I", Crashdown performs a DRADIS sweep of Kobol. The aerial survey is later presented to the President. For a brief moment, as Roslin takes the survey image out of Billy Keikeya's hand, the DRADIS information printed on the image is visible. The letters on the image are clear and are as follows:
Aerial Survey
D. 41376
Ra. 145.8
Dis. 43.5
The letters represent numerical values. While this is not conclusive evidence, it is consistent with the original manuscript definition.
Title: Re: DRADIS acronym -
Post by: Thaeris on October 06, 2012, 07:15:35 pm
Perhaps the sensor...

Determines the range* to a given contact group and then determines the sphere of infulence** of the contact group?

That actually may be a novel way of dealing with a massive number of contacts at once. For instance in a modern radar set, you may have a Range-While-Search mode (RWS), which will cover a broad range of contacts, but the set itself is rather passive - the radar will need to go into Single-Target-Track (STT) to pick a target to actively lock on to. Track-While-Scan (TWS), however, will actively keep dibs on many contacts simultaneously, but has a limit on how many it can track at any given time.

Thus, if you can break contacts up into large formations, and then break a selected formation down into multiple elements, you can deal with a very large number of contacts while not over-stressing on processing power (that may be a bit too 1980's, but all the aircraft I grew up loving had those limitations :p ). Combine that with a combat datalink, and you've got a great spread of data communication within a battlegroup.

* range => RA
** sphere of influence => diameter of a contact area => distance => DIS
Title: Re: DRADIS acronym -
Post by: Itsalive on October 08, 2012, 09:53:16 pm
I think it might be better explained in Astronomical terms.
D = Direction as in compass degrees with the ships nose being 0 degrees (yaw)
RA = Right Ascension  which is in degrees also with the horizon being 0 and directly overhead being 90 deg. and -90 for directly below (pitch)
DIS = Distance to target.
That would give you a 3 dimensional position reference
Title: Re: DRADIS acronym -
Post by: Ace on October 09, 2012, 02:01:37 pm
It's direction, range, and distance since it's a modified version of the RADAR acronym.
Title: Re: DRADIS acronym -
Post by: General Battuta on October 09, 2012, 02:22:42 pm
It's direction, range, and distance since it's a modified version of the RADAR acronym.

I don't follow. Radio detection and ranging somehow maps to direction, range and distance?
Title: Re: DRADIS acronym -
Post by: Herra Tohtori on October 09, 2012, 03:17:19 pm
I think it might be better explained in Astronomical terms.
D = Direction as in compass degrees with the ships nose being 0 degrees (yaw)
RA = Right Ascension  which is in degrees also with the horizon being 0 and directly overhead being 90 deg. and -90 for directly below (pitch)
DIS = Distance to target.
That would give you a 3 dimensional position reference

I would otherwise agree but in astronomy context Right Ascension means the target's horizontal separation from a given reference point, and declination is its elevation from horizontal plane.

Reference point in astronomy is typically the point of vernal equinox; in three-dimensional coordinate system for a battlestar, you would probably use the direction of the bow as the fixed point of reference.

Right ascension in astronomy is typically given in hours, minutes and seconds (24 hours to full circle, 60 minutes to an hour, 60 seconds to a minute) because in the Equatorial coordinate-system, objects on celestial sphere seem to move due to Earth's rotation, and it made sense to bind their horizontal location with that horizontal movement; this was useful for porting the equatorial coordinates into local horizontal coordinates which are usually given in altitude (elevation from horizon) and azimuth (distance from north in degrees), both given in degrees.

Declination is given in degrees of angle above (or below) the equator.

The analogy of Equatorial coordinates vs Horizontal coordinates regarding the DRADIS is that if DRADIS used Declination, Right ascension and Distance, that means the navigational program would generate a reference coordinate system that would be the same for all ships, and movement in that system would be relative to this coordinate system. This would make some sense, as then the DRA coordinates of targets would remain constant even if your ship turned towards them or away from them; if all ships in your group used the same reference point, then you could use the same coordinate system to relay position information directly to other ships WITHOUT having them always convert the given values into their own local Horizontal coordinate system, in which the reference point would probably be the forward direction and the local "up" of the ship.

Perhaps the lead ship of a group of ships always transmits their initial reference frame to other ships' DRADIS systems and everyone uses this reference frame for the time they remain in the same system.

Note that ships in Ragtag Fleet always seem to perform jumps with same heading - perhaps this is to facilitate faster DRADIS synchronization, or something.


Quote from: http://en.battlestarwiki.org/wiki/DRADIS
The "Direction, RAnge, and DIStance" breakdown of the acronym "DRADIS" was listed in an early manuscript of the first half of the Miniseries. Since some major elements of this script were changed (such as Kobol being the sole home of the Colonies, and not separate worlds) in comparison to the completed teleplay, canonical use of this breakdown should be taken with some skepticism.

There is some evidence to suggest that the original breakdown is the canonical version. In "Kobol's Last Gleaming, Part I", Crashdown performs a DRADIS sweep of Kobol. The aerial survey is later presented to the President. For a brief moment, as Roslin takes the survey image out of Billy Keikeya's hand, the DRADIS information printed on the image is visible. The letters on the image are clear and are as follows:
Aerial Survey
D. 41376
Ra. 145.8
Dis. 43.5
The letters represent numerical values. While this is not conclusive evidence, it is consistent with the original manuscript definition.

Well, the problem here is this:

Direction = 41376
Range     = 145.8
Distance  = 43.5

...sense, these values make none.

Even if you interpret the DRADIS acronym as Declination, Right Ascension, Distance, you get

Declination         41376
Right Ascension   145.8 
Distance                43.5

...it still doesn't make perfect sense because 41376 doesn't fit in any angular units I ever heard of.

I would expect D (be it direction or declination) to be given in degrees. Right ascension in astronomy is typically given as degrees but can be easily converted to degrees, so the RA value in this example fits.

However, if you swap the D. and Dis. values, you get this:


Declination         43.5  (degrees)
Right Ascension    145.8  (degrees)
Distance         41376  (metres)


...which makes sense in that it gives two reference points for direction and one for range, which is what you can work with in a polar equatorial coordinate system.

Given this consideration, my most likely explanation for that "aerial survey" thing is that they dun goofed.


Even if we considered that a goof-up, this still isn't any actual proof that this is what the DRADIS acronym would stand for. It would make some sense, but it isn't any sort of proof.


For all we know, DRADIS may not even be an official acronym but just something that sensor operators began using for reading out information readings, or for these two values always being shown in close proximity on the screen and being easy to pronounce together... and before you know it everyone starts to use the term.
Title: Re: DRADIS acronym -
Post by: newman on October 09, 2012, 03:28:49 pm
I suspect this thread put way more thought into what DRADIS means than the show's writers ever did.
Title: Re: DRADIS acronym -
Post by: Colonol Dekker on October 09, 2012, 03:57:20 pm
Splurge-Dis.
Title: Re: DRADIS acronym -
Post by: Horizon on October 10, 2012, 02:16:55 pm
I think it might be better explained in Astronomical terms.
D = Direction as in compass degrees with the ships nose being 0 degrees (yaw)
RA = Right Ascension  which is in degrees also with the horizon being 0 and directly overhead being 90 deg. and -90 for directly below (pitch)
DIS = Distance to target.
That would give you a 3 dimensional position reference

Having been trained and practiced in celestial navigation, this actually stands a lot of reason. 
Title: Re: DRADIS acronym -
Post by: Sobbsy on October 10, 2012, 10:11:20 pm
Before I read the 'canon' explanation of the term, I always assumed it stood for Direction, RAdius, DIStance... I assumed Radius because there's clearly a spherical radius around the source vessel that it scans beyond.
Title: Re: DRADIS acronym -
Post by: Colonol Dekker on October 12, 2012, 04:49:31 pm
Well that just sounds needless..