Re: From Raymarine Time change on GPS satellite constellation worldwide


 

Eric,

I believe you are mostly correct, but let me add something.

Your boat's GPS position is based on the elapsed time for a signal to be received from the satellite by your GPS normally utilizing 3 or more satellites that fall in line-of-sight to your boat. Longitude is based on time, but has no impact on the calculation performed in a Furuno GPS. 

The error that was experienced during the last rollover had to do with the "year calculation," but not the difference in signal travel time. I saw a Furuno GP80 (very common on SMs) operating perfectly, but with the wrong year associated with the date and time. I saw another GP80 working perfectly with the correct year. The difference was because of the manufacturing date by Furuno. The later made Furuno had been modified, and this modification compensated for the year issue. The later model Furuno was made in 2002. I certainly do not what will happen with other brands.

I am going to guess that any GPS made after about 2000 will be fine, and if it isn't 100% correct, this situation may only affect the year posted on the screen.

Best,

Bill Rouse
720 Winnie St.
Galveston, Texas 77550
832-380-4970



On Tue, Feb 26, 2019 at 1:33 PM eric freedman <kimberlite@...> wrote:

The last rollover was 20 years ago. Almost all Kimberlite Amel Super Maramu’s will be affected in some way with original equipment.

I wrote Raymarine and they are still analyzing what the affect will be with  respect to long lat as it is based upon time.

The Raymarine list does not list the older units, it will also affect in some way gmpcs.

 

Fair Winds

Eric

Kimberlite Amel Super Maramu #376

 

 

From: main@AmelYachtOwners.groups.io [mailto:main@AmelYachtOwners.groups.io] On Behalf Of CW Bill Rouse
Sent: Tuesday, February 26, 2019 8:58 AM
To: main@amelyachtowners.groups.io
Subject: Re: [AmelYachtOwners] From Raymarine Time change on GPS satellite constellation worldwide

 

The world is not ending as forums like Cruiser's Forum would lead you to believe.

 

I believe that it will only affect GPSs that were manufactured before the last rollover. AND, it will only affect the time/year on the screen of the GPS.

Best,

CW Bill Rouse
720 Winnie St
Galveston Island, TX 77550
+1(832) 380-4970

 

On Mon, Feb 25, 2019, 9:28 PM eric freedman <kimberlite@...> wrote:

 

http://forum.raymarine.com/showthread.php?tid=7453

 

 

 

From: main@AmelYachtOwners.groups.io [mailto:main@AmelYachtOwners.groups.io] On Behalf Of eric freedman
Sent: Monday, February 25, 2019 10:17 PM
To: main@AmelYachtOwners.groups.io
Subject: Re: [AmelYachtOwners] Time change on GPS satellite constellation worldwide

 

I found this article

 

https://www.spirent.com/blogs/positioning/2018/january/gps-rollover-week

 

 

From: main@AmelYachtOwners.groups.io [mailto:main@AmelYachtOwners.groups.io] On Behalf Of eric freedman
Sent: Monday, February 25, 2019 9:38 PM
To: main@AmelYachtOwners.groups.io
Subject: [AmelYachtOwners] Time change on GPS satellite constellation worldwide

 

I heard that every 20 years the time is adjusted in the GPS satellite constellation.

I also heard that the adjustment will occur in April this year and might affect our GPS units and navigation items.

Has anyone else heard about this?

Fair Winds

Eric

Kimberlite Amel Super Maramu #376

 

Join main@AmelYachtOwners.groups.io to automatically receive all group messages.