Naval Academy GPS Error Plot

[Ken Coit]

At the Naval Academy link below is a Java application that seems to take forever to load and run, but even on this old machine (300 MHz) it did finally run. What it shows is another example of GPS errors over a 6 hour period.

I plan to contact the source of this to find out what equipment he is using to track the Rickover building, but it is clear that GPS in its Standard Positioning System form is not good enough in at least some locations for anchor alarms, let alone precise navigation of channels. Those with GPS driven autopilots beware!

Keep on sailing,

Ken Coit, ND7N
CD/14 #538
CD/36 #84 Parfait
Hailing Port: Raleigh, NC
Sailing from: Beaufort, NC



parfaitNOSPAM@nc.rr.com

[Frank Vernet]

It's a funny thing -- as much time as I spent sitting in Rickover Hall, I never felt it moving and the view never changed!

A related story:

In the early 1980's Nimitz Library, which is located adjacent to Rickover Hall, was also moving. Only it was moving vertically - as in down! Rumor had it that the architects neglected to account for the weight of the books and the building was slowly sinking into the Severn River! Not sure what the engineers did to arrest the settling, but Nimitz Library still stands today.

Frank Vernet
Sirius
CD33 #84

[Ken Coit]

I have copied the entire notice below, but you can check it out at the link.

NOTICE TO MARINERS



INTERFERENCE TO GPS RECEIVERS FROM CONSUMER ELECTRONICS-GRADE ACTIVE VHF/UHF MARINE TELEVISION ANTENNAS





It has come to the attention of the U.S. Coast Guard and Federal Communications Commission that certain consumer electronics-grade active VHF/UHF marine television antennas are causing operational degradation in the performance of GPS receivers. This interference may be realized as a display of inaccurate position information or a complete loss of GPS receiver acquisition and tracking ability and the interference interactions have been reported up to 2000 feet from the interference source. This interference has been associated in some instances with temperature extremes or proximity to a television broadcast site.



If you are experiencing recurring outages or degradation of your GPS receiver you should perform an on-off test of your TV antenna. If turning off the power to the antenna results in improvement in the GPS receiver performance, the antenna may be the source of interference in the GPS band. In that case, you should contact the manufacturer of the antenna and identify the symptoms. If the test is not positive and the GPS interference persists, you may contact the Coast Guard, Office of Spectrum Management via email at CGComms@comdt.uscg.mil or through the Coast Guard Navigation Information Service at

703-313-5900/email: nisws@navcen.uscg.mil.

Navigate cautiously,

Ken

At the Naval Academy link below is a Java application that seems to take forever to load and run, but even on this old machine (300 MHz) it did finally run. What it shows is another example of GPS errors over a 6 hour period.

I plan to contact the source of this to find out what equipment he is using to track the Rickover building, but it is clear that GPS in its Standard Positioning System form is not good enough in at least some locations for anchor alarms, let alone precise navigation of channels. Those with GPS driven autopilots beware!

Keep on sailing,

Ken Coit, ND7N
CD/14 #538
CD/36 #84 Parfait
Hailing Port: Raleigh, NC
Sailing from: Beaufort, NC

parfaitNOSPAM@nc.rr.com

[randy]

It's a funny thing -- as much time as I spent sitting in Rickover Hall, I never felt it moving and the view never changed!

A related story:

In the early 1980's Nimitz Library, which is located adjacent to Rickover Hall, was also moving. Only it was moving vertically - as in down! Rumor had it that the architects neglected to account for the weight of the books and the building was slowly sinking into the Severn River! Not sure what the engineers did to arrest the settling, but Nimitz Library still stands today.

Frank Vernet
Sirius
CD33 #84

I've always wondered where the plebes who bilged out went.....FOOTINGS!



RJcapedory@aol.com

[Neil Gordon]

I notice they didn't say anything about TV antennas interfering with traditional navigation methods, e.g., using compass, paper charts and actually looking around to see where you are.


Regards, Neil
s/v LIQUIDITY
Cape Dory 28 #167



neil@nrgordon.com

[Ken Coit]

But sometimes "convenience" is irresistable.

Keep on sailing,

Ken Coit, ND7N
CD/14 #538
CD/36 #84 Parfait
Hailing Port: Raleigh, NC
Sailing from: Beaufort, NC

I notice they didn't say anything about TV antennas interfering with traditional navigation methods, e.g., using compass, paper charts and actually looking around to see where you are.


Regards, Neil
s/v LIQUIDITY
Cape Dory 28 #167

parfaitNOSPAM@nc.rr.com

[Neil Gordon]

>>But sometimes "convenience" is irresistable.<<

Don't get me wrong... I use convenience, I just don't like to rely on it exclusively.


Regards, Neil
s/v LIQUIDITY
Cape Dory 28 #167



neil@nrgordon.com