Ipad Navigation w/o wifi or cellular

Hey Guys,

Prior to our last Bahmas trip I downloaded Plan2Nav onto my ipad to use as a backup chartplotter. I went with Plan2Nav because it uses explorer chart's data which is the best available for the bahamas and is more accurate than what is loaded into my raymarine navionics softwear.

Problem is (duh on me) we generally do not have wifi or cellular while we are over there so the gps function on the ipad did not work.

Any ideas? Is there a gps antenna or ap available for ipad that would be compatible with Plan2Nav?

This was discussed in the past ... you do not need the Wi-Fi nor 3G/4G/cellular service to use GPS function on your GPS equipped iPad. Note that you need an iPad that has cellular capabilities to have a GPS enable device as the GPS and cellular functions are built into one chipset on iPads.

Once you have GPS enabled device you only need a clear view of sky to use GPS functionality of your device. You might need some sort of connectivity to download the nav apps and relevant charts for offline use. After that you do not need any connectivity ... no need for a plan/contract with any cell carrier, and SIM does not have to be activated for GPS function to work.

Hope this helps ...

Bad Elf. Plugs into your iPad. < $100.

+1 on the Bad Elf GPS receiver ...

This will make your iPad GPS capable if it is not already.

Thanks, my ipad does not have cellular capabilities. I'll check out the bad elf.

Doug

We use a Dual XGPS150 GPS on our steel trawler. It's bluetooth so we can place the receiver close to the windows and connect with our iPad. Otherwise we have poor GPS reception in the pilothouse.

Rsysol said:

We use a Dual XGPS150 GPS on our steel trawler. It's bluetooth so we can place the receiver close to the windows and connect with our iPad. Otherwise we have poor GPS reception in the pilothouse.

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Have one of these that I used with my old ipod (which does not have gps built in). Plan to use it with my iphone and ipad on the boat, even though both have built in gps, as I understand that the external puck may make positioning more accurate, especially when out of cell range as the iphone/ipad uses cell tower triangulation(?) to supplement the accuracy of the built in gps. Can anyone confirm this?

The better GPS receiver, the better view of sky, the better signal, and the better GPS accuracy.

The cell network based position augmentation works in urban areas/canyons with many cell towers all around you where GPS signal might be obscured by buildings. Do not count on it too much near shore with the towers far apart and/or on one side only.

The well positioned good GPS receiver is all what you need on an open water.

dwhatty said:

...as the iphone/ipad uses cell tower triangulation(?) to supplement the accuracy of the built in gps. Can anyone confirm this?

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This is true of the wifi-only iPad. The wifi/cellular iPads have a stand-alone GPS/Glonas receiver in them and need no connectivity whatsoever to display an accurate position. I have related before that I've used my iPad in the mountains of China and in the Middle East, and Brazil, and most recently in Australia, Malaysia, and France, to track our posiition on the roads and even show us a route to our destination. It does this using previously downloaded maps and its GPS/Glonas reciever.

It does this with the wifi and cellular connectivity buttons in the settings screens both turned off. So zero connectivity. And its positioning is dead-on accurate (or as accurate as GPS signals allow these days). In the case of the street map app that I use, if I zoom in close enough it will show us which side of the freeway we're driving on.

In the case of the Navimatics charting app we use on the boat, when we're in our home marina and I zoom in on the display, it shows us which slip we're in.

Obviously, the iPad has to be able to see the satellites. So it's not going to give a good position if you're in a tunnel. But neither does my stand-alone Garmin automotive GPS.

You don't need a celluar account--- as I said, when we're using our iPad for tracking on land or water the wifi and cellular connectivity are turned off. But you do need a cellular-capable iPad because they're the only ones with the independent GPS/Glonas receiver.

Otherwise the position display is dependent on cell tower triangulation, and cell signals are few and far between in the Chinese mountains.

Marin said:

It does this with the wifi and cellular connectivity buttons in the settings screens both turned off.

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To clarify, are you saying that one should turn these settings to "off" when using a cellular capable ipad, or an iphone, for more accurate navigational positioning? And that an external gps puck then is not necessary?

dwhatty said:

as the iphone/ipad uses cell tower triangulation(?) to supplement the accuracy of the built in gps. Can anyone confirm this?

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"Supplement the accuracy" is the wrong phrase. The GPS chips in the various phones will use known WiFi locations and cell tower triangulation to determine ephemeris data (read about ephemeris in Wikipedia). By knowing an approximate position on Earth, it can determine which satellites should be in view and can spend more time looking for them instead of scanning for the entire constellation of satellites. Once it gets 3-4 satellites, it'll lock the position with full GPS accuracy.

So the WiFi and cellular capabilities won't provide anything in terms of better accuracy but it will provide a faster time-to-first-fix and that's why it's used. From my understanding, cellular triangulation happens independent of whether you have a cellular plan. I find that my iPad without cellular plan locks onto it's position about as fast as my iPhone does.

Dwatty, no.

dwhatty said:

To clarify, are you saying that one should turn these settings to "off" when using a cellular capable ipad, or an iphone, for more accurate navigational positioning? And that an external gps puck then is not necessary?

Click to expand...

No. I turn the connectivity off when I'm in another country (including across the border in Canada) to ensure that I don't do something on the device that would cause it to run up unwanted data or phone charges. Turning the connectivity off makes no difference to the GPS side of the iPad. I simply made the point as a way of emphasizing that you do not need any connectivity with a wifi/celluar iPad to be able to take advantage of GPS tracking and accuracy.

I don't use an external GPS device--- puck--- because it's not necessary with our wifi/cellular iPads.

I don't know how any of this applies to the iPhone, by the way. My wife currently has an iPhone 5, soon to be 6, and while it is obvioulsy both wifi and cellular capable, I don't know if it contains the same kind of independent GPS/Glonas receiver as the wifi/cellular iPad. I've been assuming it doesn't, but I've not downloaded the mapping and charting apps to it that we use on land and on the boat because the screen is too small to make it useful in these applications. I suppose I should try it.......

Duel GPS

We also use the Dual XGPS150 GPS as an external GPS for our non-cellular iPad 1 (!). Connects by bluetooth and works quite well. It is one more thing to charge, but runs all day on one charge. Gives you something to do with an old iPad. I think the Dual cost about $75 several years ago.

Dan
Channel Islands, CA

I went to the Tab4 after Apple made my iPad one pretty much worthless.