What this discussion is missing is the distinction between stand alone gps and 
assisted or augmented gps found in most mobile or cellular devices. Mobile 
devices having cell service or internet provider can augment gps. If the mobile 
device has no gps and no cell service it can still get a position from WiFi 
connection.  These are usually called location devices rather than gps and will 
only work with internet or cell service within range.  If the device also has a 
gps or has external gps access it will work anywhere that gps signals are 
available which is just about world wide. As long as your charts are downloaded 
on the device it should work anywhere.  The following discussion is from 
Wikipedia. 

Standalone/self-ruling GPS devices depend solely on information from 
satellites. A-GPS augments that by using cell tower data to enhance quality and 
precision when in poor satellite signal conditions. In exceptionally poor 
signal conditions, for example in urban areas, satellite signals may exhibit 
multipath propagation where signals skip off structures, or are weakened by 
meteorological conditions or tree canopy. Some standalone GPS navigators used 
in poor conditions can't fix a position because of satellite signal fracture 
and must wait for better satellite reception. A regular GPS unit may need as 
long as 12.5 minutes (the time needed to download the GPS almanac and 
ephemerides) to resolve the problem and be able to provide a correct 
location.[2]

An assisted GPS system can address these problems by using external data. 
Utilizing this system can come at a cost to the user. For billing purposes, 
network providers often count this as a data access, which can cost money, 
depending on the plan.[3]

To be precise, A-GPS features depend mostly on an internet network or 
connection to an ISP(or CNP, in the case of CP/mobile-phone device linked to a 
cellular network provider data service). A mobile (cell phone, smart phone) 
device with just an L1 front-end radio receiverand no GPS acquisition, 
tracking, and positioning engine only works when it has an internet connection 
to an ISP/CNP, where the position fix is calculated offboard the device itself. 
It doesn't work in areas with no coverage or internet link (or nearby base 
transceiver station (BTS) towers, in the case on CNP service coverage area). 
Without one of those resources, it can't connect to the A-GPS servers usually 
provided by CNPs. On the other hand, a mobile device with a GPS chipset 
requires no data connection to capture and process GPS data into a position 
solution, since it receives data directly from the GPS satellites and is able 
to calculate a position fix itself. However, the availability of a data 
connection can provide assistance to improve the performance of the GPS chip on 
the mobile device.

Sent from my iPhone

> On Jan 19, 2019, at 10:56 AM, T power via CnC-List <cnc-list@cnc-list.com> 
> wrote:
> 
> Hi Bruce,
> 
> I was thinking of using a Samsung tablet also. Do you happen to sail 
> offshore, If so are you still able to run a Nav program in real time when out 
> of range of cell and wifi?
> 
> Cheers,
> 
> Tom Power
> Invictus
> C&C 30 MK1
> Fredericton, NB
> From: CnC-List <cnc-list-boun...@cnc-list.com> on behalf of Bruce Whitmore 
> via CnC-List <cnc-list@cnc-list.com>
> Sent: Saturday, January 19, 2019 9:43 AM
> To: Rick Brass via CnC-List
> Cc: Bruce Whitmore
> Subject: Re: Stus-List Tablet for navigation
>  
> Hello all,
> 
> I am going to mildly disagree with the statements about tablets having to be 
> cellular capable.  I have an old (2014) Samsung Galaxy 10.1 tablet that is 
> wifi only, and it has GPS capability that I have used on my boat.
> 
> So while that statement might be right for other makes and models, it is not 
> correct for my tablet.
> 
> Kindest Regards, 
> 
> Bruce Whitmore
> 
> (847) 404-5092 (mobile)
> bwhitm...@sbcglobal.net
> 
> 
> 
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