RE: Pulsar Nav accuracy

Another way to look at it:
Pulsar A and B form a "known" line of known distance. So an analogy is a
tall pine tree growing on flat ground, Pulsar A is the base, Pulsar B
the top.  If I stand somewhere and get an angle to the base and an angle
to the top, in your argument I would know exactly where I was.	The
problem is, if I walk in a circle at exactly the same distance away from
the tree, the angle looking down to the base is always going to be the
same and the angle looking up to the top is always going to be same as I
measured before. Does that mean that even though I walked somewhere, I'm
still in the same spot?  You need that third point to determine where on
the circle you are. 

--Binhan

> -----Original Message-----
> From: hal@buffnet.net [mailto:hal@buffnet.net]
> Sent: Tuesday, February 26, 2002 9:10 PM
> To: gzg-l@csua.berkeley.edu
> Subject: Re: Pulsar Nav accuracy
>
> Lets say for the sake of argument, that I attempt to take a bearing on
> Pulsar A.  I get that bearing.  At the same time, I have 
> someone else, or
> the computer take readings automatically) that gets the 
> bearing on Pulsar
> B.  For this "exercise" I have the bearings on both known 
> Pulsars, along
> with their *known* 3d co-ordinates.  From those two known 
> co-ordinates, I
> should be able to compute the third co-ordinate (my 
> location).  This is why
> I am confused as to why it should require more than *two* 
> pulsars...  Mind
> you, I'm not saying "exact" co-ordinates down to precision values, but
> general ball park at least.
> 
>	 Hal
>