[NatureNS] GPS deal - spatial resolution

From: Christopher Majka <c.majka@ns.sympatico.ca>
To: naturens@chebucto.ns.ca
Date: Tue, 20 Oct 2009 10:44:13 -0300
References: <d15.5570b072.380f105c@aol.com>
Precedence: bulk
Return-Path: <naturens-mml-owner@chebucto.ns.ca>
Original-Recipient: rfc822;"| (cd /csuite/info/Environment/FNSN/MList; /csuite/lib/arch2html)"

next message in archive
next message in thread
previous message in archive
previous message in thread
Index of Subjects

Index of Subjects

--Apple-Mail-594-713663003
Content-Type: text/plain;
	charset=US-ASCII;
	format=flowed;
	delsp=yes
Content-Transfer-Encoding: 7bit

In addition to GPS, the Russians have a global navigation satellite  
system called GLONASS  the "GLObal NAvigation Satellite System" in  
English) which began its implementation in 1982. After the end of the  
Soviet Union it fell into disrepair but commencing in 2001 the Russian  
government, in partnership with the Indian government, has been  
rebuilding the system so that it now consists of 20 satellites and  
covers 80% of the globe. There are plans to launch an additional 10  
satellites so that by 2011 they will have achieved 100% coverage of  
the planet. As of May 18, 2007 this system is now available free of  
charge to civilians. It has a horizontal accuracy of 50-70 meters.

http://en.wikipedia.org/wiki/GLONASS

The European Union and the European Space Agency are also working on a  
global navigation satellite system called Galileo which is slated to  
become operational in 2013. There will be a free Open Service (OS)  
available to everyone which will have a horizontal accuracy of < 4 m  
and an encrypted Commercial Service (CS) which will offer a horizontal  
accuracy of < 1 m! This signal can then be combined with signals from  
ground stations to bring the accuracy to < 10 cm. Astonishing!

http://en.wikipedia.org/wiki/Galileo_positioning_system

The Chinese also want to build a system called Compass, but it seems  
to be mostly in a testing planning stage. Only one satellite has been  
launched and I don't know if there is even a projected date by which  
it might be operational.

http://en.wikipedia.org/wiki/Compass_navigation_system

Cheers!

Christopher Majka
(ancient mariner)

On 20-Oct-09, at 10:08 AM, Hubcove@aol.com wrote:

> As Chris said, the degrading of the GPS position was very much a US  
> policy, apparently  primarily to degrade targeting information. The  
> way major manufacturers got around the problem was by marketing  
> Differential GPS. Receivers in significant navigation locations,  
> Chebucto Head for example, received the GPS signal, compared it to  
> the actual position of the receiver and transmitted the correction  
> to shipborne receivers on a frequency of around
> 300khz. Prior to that, while the absolute accuracy of GPS was  
> superior to Loran, the relative accuracy with Loran was very high.  
> In other words, if you put something in the water and noted the  
> Loran reading, it would still be very close to the same reading when  
> you came back, assuming of course it was anchored. Loran errors can  
> be quite large, but are generally constant.
>
> Peter Stow
> (ancient sea captain}
> Hubbards


--Apple-Mail-594-713663003
Content-Type: text/html;
	charset=US-ASCII
Content-Transfer-Encoding: quoted-printable

<html><body style=3D"word-wrap: break-word; -webkit-nbsp-mode: space; =
-webkit-line-break: after-white-space; "><div>In addition to GPS, the =
Russians have a&nbsp;global navigation satellite system called GLONASS =
&nbsp;the "GLObal&nbsp;NAvigation&nbsp;Satellite&nbsp;System" in =
English) which began its implementation in 1982. After the end of the =
Soviet Union it fell into disrepair but commencing in 2001 the Russian =
government, in partnership with the Indian government, has been =
rebuilding the system so that it now consists of 20 satellites and =
covers 80% of the globe. There are plans to launch an additional 10 =
satellites so that by 2011 they will have achieved 100% coverage of the =
planet. As of May 18, 2007 this system is now available free of charge =
to civilians. It has a horizontal accuracy of 50-70 =
meters.</div><div><br></div><div><a =
href=3D"http://en.wikipedia.org/wiki/GLONASS">http://en.wikipedia.org/wiki=
/GLONASS</a></div><div><br></div><div>The European Union and the =
European Space Agency are also working on a&nbsp;global navigation =
satellite system called Galileo which is slated to become operational in =
2013. There will be a free Open Service (OS) available to everyone which =
will have a horizontal accuracy of &lt; 4 m and an encrypted Commercial =
Service (CS) which will offer a horizontal accuracy of &lt; 1 m! This =
signal can then be combined with signals from ground stations to bring =
the accuracy to &lt; 10 cm. =
Astonishing!&nbsp;</div><div><br></div><div><a =
href=3D"http://en.wikipedia.org/wiki/Galileo_positioning_system">http://en=
.wikipedia.org/wiki/Galileo_positioning_system</a></div><div><br></div><di=
v>The Chinese also want to build a system called Compass, but it seems =
to be mostly in a testing planning stage. Only one satellite has been =
launched and I don't know if there is even a projected date by which it =
might be operational.</div><div><br></div><div><a =
href=3D"http://en.wikipedia.org/wiki/Compass_navigation_system">http://en.=
wikipedia.org/wiki/Compass_navigation_system</a></div><div><br></div><div>=
Cheers!</div><div><br></div><div>Christopher Majka</div><div>(ancient =
mariner)</div><br><div><div>On 20-Oct-09, at 10:08 AM, <a =
href=3D"mailto:Hubcove@aol.com">Hubcove@aol.com</a> wrote:</div><br =
class=3D"Apple-interchange-newline"><blockquote type=3D"cite"> <div =
style=3D"FONT-FAMILY: Arial; COLOR: #000000; FONT-SIZE: 10pt" =
id=3D"role_body" bottommargin=3D"7" leftmargin=3D"7" rightmargin=3D"7" =
topmargin=3D"7"><font id=3D"role_document" color=3D"#000000" size=3D"2" =
face=3D"Arial"> <div><font size=3D"3">As Chris said, the degrading of =
the GPS position was very much a US policy, apparently &nbsp;primarily =
to degrade targeting information. The way major manufacturers got around =
the problem was by marketing Differential GPS. Receivers in significant =
navigation locations, Chebucto Head for example, received the GPS =
signal, compared it to the actual position of the receiver and =
transmitted the correction to shipborne receivers on a frequency of =
around</font></div> <div><font size=3D"3">300khz. Prior to that, while =
the absolute accuracy of GPS was superior to Loran, the relative =
accuracy&nbsp;with Loran was very high. In other words, if you put =
something in the water and noted the Loran reading, it would still be =
very close to the same reading when you came back, assuming of course it =
was anchored. Loran errors can be quite large, but are generally =
constant.</font></div> <div><font size=3D"3"></font>&nbsp;</div> =
<div><font size=3D"3">Peter Stow</font></div> <div><font =
size=3D"3">(ancient sea captain}</font>&nbsp;&l