Cell Phone use on open water

[Lanny]

Looking for some information. I currently have a Garmin iQue M5 PDA/GPS that I use for hunting with topo maps and as a backup to my chartplotter on my boat using NOAA free maps. This unit is starting to show signs of failing. I am looking at replacing it with another PDA/GPS or preferable a iphone, droid, windows 7 phone, etc. I have several questions I have not been able to get answered talking to the phone people from the various services(att, Verizon, etc)

Below are some of the questions I have and was hoping that some of the boaters on here may be using them and can shed some light.

1. Make and models of phones you are using out in the open water?
2. Some of these phone use aGPS and/or GPS. If 12 miles off shore and no cell service will the aGPS still track and keep
showing your current location or do they only use the cell towers to triangulate your location?
3. Do I need to get a phone that has GPS and aGPS if they make them? Brand, model?????
4. Software or apps for these phones…and recommendations? I have seen one by memory-map.com that makes the
software I use on my PDA now makes an app that can be used on and iPhone
http://www.memory-map.com/mm-iphone.htm . Has anyone tried it on an iPhone and not have cell service?
5. What about apps for the other phones?

Thanks for any help you can provide.
Lanny

 

[Workdog]

I have a Blackberry Curve with internal GPS capability. Compared to a Garmin/whatever handheld GPS, the Curve's GPS capability and functions are limited. In the case of Blackberry, you can get positional info through either the GPS function or through tower triangulation. Triangulation position accuracy can be very gross depending on tower location and numbers. The GPS function may cost you a monthly fee of $10 or so. In a year's time, you could have paid for a better GPS. The worse thing for me with a cell phone GPS is, anyone with the knowhow could track wherever you are, even when the GPS app is not running.

 

[Grog]

Droid, built in GPS and downloadable maps. Be sure you download the maps beforehand.

 

[Lanny]

Droid, built in GPS and downloadable maps. Be sure you download the maps beforehand.

I assume you mean to download the maps at home and not expect to download over the air.

 

[GWTour275]

I have a Droid, Google maps eliminates the need for a GPS totally. Can you download marine maps for this? This would be a great Backup for my 4212.

 

[Lanny]

From what I understand if you are using Google maps you have to have cell service to keep the maps updated. If you get off route and you don't have cell service the maps won't update, you may still have GPS and a track but when you run out of the current map I don't know what will happen. Will the track still show on a blank screen or will it quit? That is why I want to be able to download maps and make sure it is using true GPS and not thru cell service.

 

[Pez Vela]

I use an iPhone for general cell phone purposes. I have had an iPhone 3G, and I now have an iPhone 4. Each of these cell phones have internal GPS antennas. These are true GPS machines and do not need cellular coverage to provide location services. iPhones may be loaded with the Navionics marine app (or apps) for your geographical area. The apps are available for purchase through the iTunes app store. Purchase of the Navionics app includes all the charts for your area of interest, and they are thus embedded in your iPhone and travel with you. No cellular service is needed to update the charts as your position on the water changes. The opposite is true for the Google Maps app which comes with the iPhone. As you travel on land within cellular coverage areas, the land based maps are updated by cellular transmission. If you lose cell coverage, your iPhone will not update the land based maps. That is why, for hunters and land based explorers who venture beyond cellular coverage areas, it is important to purchase an appropriate app which includes embedded maps for the area of interest. Then, the GPS land based functions will be fully capable, just like on the water ... no cellular service required.

Of course on the water, my iPhone only serves a backup GPS chartplotter for my dedicated marine electronics. Having the iPhone do double duty is a very nice feature indeed.

Here's some real world info on how "assisted" GPS (AGPS) works on the iPhone. The "assist" comes from cellular tower triangulation to establish your location. Since the iPhone's GPS antenna draws power, it may be turned "on" and "off" independently from the iPhone itself, in order to conserve battery power. If you launch Google Maps (for example) with the GPS antenna turned "off," the iPhone will locate your position using cellular tower triangulation. It will not be very accurate in my experience. The only time you might need to rely on cellular triangulation (that I can think of) would be when you have no clear view to the sky for GPS satellite reception, such as when you are inside a building or in a downtown area surrounded by tall buildings (I experienced this in San Francisco). So, the moral of the story is : power "on" the iPhone's internal GPS antenna when you want to use it, and don't be confused by phones (with no GPS antenna) which only use cellular triangulation to provide so-called location information.

 

[NOTHING ELSE MATTERS]

I agree with Pez in almost everything. I also have and used before an i phone 4 as a back on my boat, but just to try it( i have downloaded the Navionics maps), i would never rely on a smart phone as a back up. What i have besides my twin Garmin 4212's is a Garmin 76Cx which is the BEST choice by far for a back up unit. I change the 2 AA batteries in the beginning of the season which last the whole season and beyond. If you go with the 76(non color) you'll forget when you changed the batteries. I keep mine in the ditch bag along with the Standard Horizon HX850S, great combo.

 

[Lanny]

Here's some real world info on how "assisted" GPS (AGPS) works on the iPhone. The "assist" comes from cellular tower triangulation to establish your location. Since the iPhone's GPS antenna draws power, it may be turned "on" and "off" independently from the iPhone itself, in order to conserve battery power. If you launch Google Maps (for example) with the GPS antenna turned "off," the iPhone will locate your position using cellular tower triangulation. It will not be very accurate in my experience. The only time you might need to rely on cellular triangulation (that I can think of) would be when you have no clear view to the sky for GPS satellite reception, such as when you are inside a building or in a downtown area surrounded by tall buildings (I experienced this in San Francisco). So, the moral of the story is : power "on" the iPhone's internal GPS antenna when you want to use it, and don't be confused by phones (with no GPS antenna) which only use cellular triangulation to provide so-called location information.

Thanks for the very informative information. I have a question....when you say no GPS antenna....does a phone listed as aGPS only use cell tower or does it use both cell tower and GPS or do I need to make sure it says GPS receiver?

Lanny

 

[Pez Vela]

The short answer is "make sure." Marketing can be misleading.

 

[Tashmoo]

Get a marine grade, water proof GPS and hand held VHF for a backs up, don't rely on a cell phone.

I am not sure about others but my cell phone craps out about 15 miles off shore (type EVO 4G) it also will kill a battery in about an hour once it loses signal looking for the 3G/4G and GPS signals so you have to keep it on a charger not that they are worth anything once you are out of range. The GPS function as I understand it needs the cell towers so once you are out of range you are SOL. Also, as I understand it the Coast Guard is not wild about taking distress calls from a cell phone and has enacted new rules regarding them, you should understand the rules if you intend to use one as a back up to your VHF. Finally, last year I had my Blackberry in the starboard console out of the elements, took a roller and buried the bow soaked myself and the phone on a nice sunny day. Phone was DOA, hence the new EVO.

Simply put they are a poor back up, I would not take the risk, but that’s me.

 

[Pez Vela]

The GPS function as I understand it needs the cell towers so once you are out of range you are SOL.

Try turning it on and report back. Maybe you have a phone problem.

On the Home screen tap Menu > Settings > Location > Use GPS satellites.

 

[Lanny]

The GPS function as I understand it needs the cell towers so once you are out of range you are SOL.

Try turning it on and report back. Maybe you have a phone problem.

On the Home screen tap Menu > Settings > Location > Use GPS satellites.

Pez,
I have a couple of questions that I am having problems finding answers too about the GPS receiver in the iPhone. Do you know the maximum number of satellites the GPS receiver can monitor and is it WAAS enabled?

Lanny

 

[Pez Vela]

Sorry, I do not know those details. I can say that, for me, the GPS accuracy and signal acquisition time of the iPhone is not noticeably different from my marine GPS unit.

 

[ocnslr]

Hey Tashmoo,

Put your EVO in "Airplane mode" and it will stop all 3G and 4G communications. Make sure GPS is on, and you can use it as a backup - if you like.

I put it in Airplane mode and use it as an MP3 player...

 

[Grog]

^
exactly

 

[Tashmoo]

Thanks, I will try both suggestions when we get rid of all the snow sometime in April, I hope!

 

[Workdog]

I have a Blackberry Curve with internal GPS capability. Compared to a Garmin/whatever handheld GPS, the Curve's GPS capability and functions are limited. In the case of Blackberry, you can get positional info through either the GPS function or through tower triangulation. Triangulation position accuracy can be very gross depending on tower location and numbers. The GPS function may cost you a monthly fee of $10 or so. In a year's time, you could have paid for a better GPS. The worse thing for me with a cell phone GPS is, anyone with the knowhow could track wherever you are, even when the GPS app is not running.

Check this youtube vid for info on geotagging: http://www.youtube.com/watch?v=N2vARzvW ... detailpage