On my return trip from the Robinhood Rendevous I experienced a complete loss of GPS coverage on two separate occasions(all data fields went blank). Both events occurred during periods of heavy rain. The loss of signal, I assume occurred due to the intensity of the rain. My GPS is a sternrail mounted Garmin 45 on a CD27.
I've used Loran in intense rain on several occasions and never missed a beat.
It made me reflect on the importance of dead reckoning and tracking position. Has anyone out there had a similar experience.
Craig Urquhart
Satu CD27 #272
Satu@gwi.net
Loss of GPS Coverage In Heavy Rain
Moderator: Jim Walsh
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Neil Gordon
Re: Loss of GPS Coverage In Heavy Rain
>>...I experienced a complete loss of GPS coverage ...<<
Hasn't happened to me, but my mom taught me to stay out of the rain. <g> Doesn't surprise me that heavy rain would block the signal. GPS doesn't work indoors, either. I get an occasional loss of signal under the dodger.
You're right about keeping a dead reckoning. My practice is to take a GPS fix at reasonable time intervals... fixes closer together the closer I am to things I don't want to be closer to <s>... and I log the fixes. That way, if I lose the GPS, I have a record of where I was, probably no more than 30 minutes ago.
Even in familiar coastal waters, it's a good idea to take and record your position. Could be you find yourself over the side and out of sight, and your inexperienced crew is trying to tell the CG where you are. Easier to tell them that you're writing your last position and the time in this here notebook than to give them a quick lesson on GPS operation. (Besides, with a handheld, sometimes the GPS goes overboard, too. <g>)
Regards, Neil
s/v LIQUIDITY
Cape Dory 28 #167
neil@nrgordon.com
Hasn't happened to me, but my mom taught me to stay out of the rain. <g> Doesn't surprise me that heavy rain would block the signal. GPS doesn't work indoors, either. I get an occasional loss of signal under the dodger.
You're right about keeping a dead reckoning. My practice is to take a GPS fix at reasonable time intervals... fixes closer together the closer I am to things I don't want to be closer to <s>... and I log the fixes. That way, if I lose the GPS, I have a record of where I was, probably no more than 30 minutes ago.
Even in familiar coastal waters, it's a good idea to take and record your position. Could be you find yourself over the side and out of sight, and your inexperienced crew is trying to tell the CG where you are. Easier to tell them that you're writing your last position and the time in this here notebook than to give them a quick lesson on GPS operation. (Besides, with a handheld, sometimes the GPS goes overboard, too. <g>)
Regards, Neil
s/v LIQUIDITY
Cape Dory 28 #167
neil@nrgordon.com
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Don Carr
Re: Loss of GPS Coverage In Heavy Rain
I have never experienced total 'blackout'. Howver I have experienced errors beyond SA where I have lost all but 2 satellites. This has occured on heavy overcast days.On my return trip from the Robinhood Rendevous I experienced a complete loss of GPS coverage on two separate occasions(all data fields went blank). Both events occurred during periods of heavy rain. The loss of signal, I assume occurred due to the intensity of the rain. My GPS is a sternrail mounted Garmin 45 on a CD27.
I've used Loran in intense rain on several occasions and never missed a beat.
It made me reflect on the importance of dead reckoning and tracking position. Has anyone out there had a similar experience.
Craig Urquhart
Satu CD27 #272
One must realize that GPS, like VHF is 'line of sight' and clouds i.e.
rain may refract the signal or distort the signal so that the GPS in its error correction logic discards the data from the satellites.
To reiterate Neils comment and your own and the Coast Guard's advice:
ALWAYS, ALWAYS, ALWAYS; HAVE AT LEAST 2 METODS OF NAVIGATION ACTIVE ON YOUR BOAT. IF POSSIBLE HAVE 3. Repeat that 3 times. Even LORAN has some faults.
carrd@erols.com
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Neil Gordon
Re: Loss of GPS Coverage In Heavy Rain
>>ALWAYS, ALWAYS, ALWAYS; HAVE AT LEAST 2 METODS OF NAVIGATION ACTIVE ON YOUR BOAT.<<
*Looking around* is the best and most reliable. No batteries, either. <g> You'd be amazed how many buoys get run down by boaters staring at the GPS. <g>
Regards, Neil
s/v LIQUIDITY
Cape Dory 28 #167
neil@nrgordon.com
*Looking around* is the best and most reliable. No batteries, either. <g> You'd be amazed how many buoys get run down by boaters staring at the GPS. <g>
Regards, Neil
s/v LIQUIDITY
Cape Dory 28 #167
neil@nrgordon.com
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Catherine Monaghan
Re: Loss of GPS Coverage In Heavy Rain
Craig,
There are a number of things that can cause GPS errors and blackouts. Disturbances in the ionosphere (space storms) and solar storms and flares can create enough distrubance in the signals from satellites to cause major errors and/or prevent their signals from reaching the Earth. This not only effects GPS systems but communications satellites as well. And just as a bad storm can cause "clutter" on an HF radar screen, it can reek havoc on GPS signals as well.
The DOD and DOT which control the GPS system can also degrade the system (selective availability) as well as cause blackouts.
You can check the <a href="http://www.navcen.uscg.mil/gps/default.htm">USCG's website</a> for <a href="http://www.navcen.uscg.mil/gps/status/d ... m">current status information</a> regarding the GPS system and <a href="http://www.navcen.uscg.mil/gpsnotices/d ... m">planned interruptions</a>.
catherine_monaghan@merck.com
CD32 Realization
Raritan Bay
catherine_monaghan@merck.com
There are a number of things that can cause GPS errors and blackouts. Disturbances in the ionosphere (space storms) and solar storms and flares can create enough distrubance in the signals from satellites to cause major errors and/or prevent their signals from reaching the Earth. This not only effects GPS systems but communications satellites as well. And just as a bad storm can cause "clutter" on an HF radar screen, it can reek havoc on GPS signals as well.
The DOD and DOT which control the GPS system can also degrade the system (selective availability) as well as cause blackouts.
You can check the <a href="http://www.navcen.uscg.mil/gps/default.htm">USCG's website</a> for <a href="http://www.navcen.uscg.mil/gps/status/d ... m">current status information</a> regarding the GPS system and <a href="http://www.navcen.uscg.mil/gpsnotices/d ... m">planned interruptions</a>.
catherine_monaghan@merck.com
CD32 Realization
Raritan Bay
On my return trip from the Robinhood Rendevous I experienced a complete loss of GPS coverage on two separate occasions(all data fields went blank). Both events occurred during periods of heavy rain. The loss of signal, I assume occurred due to the intensity of the rain. My GPS is a sternrail mounted Garmin 45 on a CD27.
I've used Loran in intense rain on several occasions and never missed a beat.
It made me reflect on the importance of dead reckoning and tracking position. Has anyone out there had a similar experience.
Craig Urquhart
Satu CD27 #272
catherine_monaghan@merck.com