[NatureNS] GPS deal - spatial resolution

Date: Tue, 20 Oct 2009 20:10:09 -0400
From: "Paul S. Boyer" <psboyer@eastlink.ca>
To: naturens@chebucto.ns.ca
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--Boundary_(ID_Sp9StD11l1OAK198iihBgQ)
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I have a source who tells me that the military version of GPS is  
incredibly accurate.  If you let the receiver sit in the same place  
for a day, it will attain an accuracy of less than a millimeter.

On 20 Oct 2009, at 9:44 AM, Christopher Majka wrote:

> 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
>


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<html><body style=3D"word-wrap: break-word; -webkit-nbsp-mode: space; =
-webkit-line-break: after-white-space; ">I have a source who tells me =
that the military version of GPS is incredibly accurate. &nbsp;If you =
let the receiver sit in the same place for a day, it will attain an =
accuracy of less than a millimeter.<div><br><div><div>On 20 Oct 2009, at =
9:44 AM, Christopher Majka wrote:</div><br =
class=3D"Apple-interchange-newline"><blockquote type=3D"cite"><div =
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 informa