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Old 25-06-2012, 12:17   #166
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Re: To Plot, or Not ? Is a Chart Plotter a Luxury or a Necessity ?

Yes I am aware of the different models of iPad and iPhone and their relative limitations. I am also a telecommunications engineer and used to plan cell , and satellite, networks before I went sailing full-time. Whilst I don't profess to be an expert I know enough about this subject to be dangerous

Even though they have a GPS chip it uses the information from the cell network, wifi networks, and the internet, to help initialise the GPS. I can assure you that once a GPS iPad looses lock away from the networks it will often not regain lock, of if it does it can take hours to achieve a GPS lock.

I have seen this many times at sea. If you keep your iPad on and in view of the GPS satellites it can maintain lock out of range of cell networks but if it looses lock because; you have it switched off, the battery dies, or you have it down below on a metal boat, then you have a problem. The iPad and iPhone use the internet to download the ephemeris data for the GPS satellites and if the internet is not available they seem to be stuffed (again this will be most obvious if the unit has been switched off or away from internet access for some time).

I use my my iPad as an electronic library, and have iNavX on it, but mainly at sea I have tried to use it with GoSkyWatch to help identify a star that I am not sure of or something like that. That is how I discovered the problem, and I have been monitoring it with other phones and tablets since, they all suffer from the same issue.

A good handheld GPS will acquire a GPS signal from cold, in minutes at most, it much more rugged, can use AA batteries, can be waterproof, and is cheaper than an iPhone or iPad or similar. Have the correct tool in your toolbox and your job will be much easier.

Chris
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Old 25-06-2012, 12:33   #167
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Re: To Plot, or Not ? Is a Chart Plotter a Luxury or a Necessity ?

Quote:
Originally Posted by Littlechay View Post
Yes I am aware of the different models of iPad and iPhone and their relative limitations. I am also a telecommunications engineer and used to plan cell , and satellite, networks before I went sailing full-time. Whilst I don't profess to be an expert I know enough about this subject to be dangerous

Even though they have a GPS chip it uses the information from the cell network, wifi networks, and the internet, to help initialise the GPS. I can assure you that once a GPS iPad looses lock away from the networks it will often not regain lock, of if it does it can take hours to achieve a GPS lock.

I have seen this many times at sea. If you keep your iPad on and in view of the GPS satellites it can maintain lock out of range of cell networks but if it looses lock because; you have it switched off, the battery dies, or you have it down below on a metal boat, then you have a problem. The iPad and iPhone use the internet to download the ephemeris data for the GPS satellites and if the internet is not available they seem to be stuffed (again this will be most obvious if the unit has been switched off or away from internet access for some time).

I use my my iPad as an electronic library, and have iNavX on it, but mainly at sea I have tried to use it with GoSkyWatch to help identify a star that I am not sure of or something like that. That is how I discovered the problem, and I have been monitoring it with other phones and tablets since, they all suffer from the same issue.

A good handheld GPS will acquire a GPS signal from cold, in minutes at most, it much more rugged, can use AA batteries, can be waterproof, and is cheaper than an iPhone or iPad or similar. Have the correct tool in your toolbox and your job will be much easier.

Chris
All can say is that has not been my experience.
My iPad has no SMS card in it so it is permantly deactivated from the phone network. I have a metal boat so the gps will loose the fix down below as you would expect. I also frequently turn the gps off to preserve battery power. It has always reaquired the satellite fix promptly. I have flown 1/2 way around the world once again it has a very rapid fix.
I am not sure why my experience is so contrary to yours. Given my lack of phone access and a metal boat I should be experiencing the problems you describe frequently.
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Old 25-06-2012, 12:52   #168
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Re: To Plot, or Not ? Is a Chart Plotter a Luxury or a Necessity ?

I am not 100% sure of the internal workings of the iPad but you don't need a SIM card to locate onto a cell network - that's why you can make emergency calls without a SIM card in your phone, for example - so the iPad will always have the ability to know approximately where it is if it has a cell signal.

Do you use Wifi?

For how long has your iPad been inactive between acquisitions?

These are key points. Especially if we are talking about using a phone or tablet as backup offshore where they might not have been used for days or weeks.

I too fly half way around the world, literally, and regularly make voyages where I am well away from civilisation for weeks at a time. I say the problem is very real and I have seen it on OPs 'i' devices as well as on Android devices.

I'm not talking about the device having been away from the signal for a day or so here but offshore, for several days or much longer.

Even if you have flown half way around the world, provided the ephemeris data in the devices almanac is more or less up to date it should reacquire quite quickly.

Chris
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Old 25-06-2012, 13:05   #169
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Re: To Plot, or Not ? Is a Chart Plotter a Luxury or a Necessity ?

Quote:
Originally Posted by Littlechay View Post
I am not 100% sure of the internal workings of the iPad but you don't need a SIM card to locate onto a cell network - that's why you can make emergency calls without a SIM card in your phone, for example - so the iPad will always have the ability to know approximately where it is if it has a cell signal.

Do you use Wifi?

For how long has your iPad been inactive between acquisitions?

These are key points. Especially if we are talking about using a phone or tablet as backup offshore where they might not have been used for days or weeks.

I too fly half way around the world, literally, and regularly make voyages where I am well away from civilisation for weeks at a time. I say the problem is very real and I have seen it on OPs 'i' devices as well as on Android devices.

I'm not talking about the device having been away from the signal for a day or so here but offshore, for several days or much longer.

Even if you have flown half way around the world, provided the ephemeris data in the devices almanac is more or less up to date it should reacquire quite quickly.

Chris
Phone communication is turned off in preferences.
I do have wi fi, via a mifi device. The mi fi is turned off at night etc and the Internet conection can be patchy in the area that I am sailing, but it has rarely been off for more than a few days.

Certainly phone reception does not seem a prerequisite for good gps performance given my experience, but almanac data via the Internet may be necessary. I would expect if it's downloading the almanac from the Internet rather than the satellites it should be possible to download several years worth and store this. We just need someone to write an application.
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Old 25-06-2012, 13:56   #170
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Re: To Plot, or Not ? Is a Chart Plotter a Luxury or a Necessity ?

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Originally Posted by noelex 77 View Post
I think part of the problem is that some people are very uncomfortable using technology and others are uncomfortable using the paper alternatives.
I have always thought CP were very easy to use, but recently I had a very experienced salor and boat builder on board. He was a great navigator, but was totally lost learning to use a chartplotter. It would have taken weeks to get him competent using this technology.
I would encourage crusing sailors to become comfortable using all the tools.

Exactly. CGA has good classes to get one started on all of it.
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Old 25-06-2012, 16:36   #171
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Re: To Plot, or Not ? Is a Chart Plotter a Luxury or a Necessity ?

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Originally Posted by noelex 77 View Post
Certainly phone reception does not seem a prerequisite for good gps performance given my experience, but almanac data via the Internet may be necessary. I would expect if it's downloading the almanac from the Internet rather than the satellites it should be possible to download several years worth and store this. We just need someone to write an application.
Unfortunately it's not as easy as downloading several years worth of data. The satellites are in quite dynamic orbits, being affected by a myriad of forces, the positioning maneuvers to keep them in the correct orbit are not perfect and their clocks are not perfect, satellites fail and are switched on and off depending on operational requirements etc. etc.. so the satellite emphemeris is a pretty dynamic thing - not hour-to-hour or day-to-day, but certainly from week to week significant errors can creep in.

Well this is off topic so I'll shut up.

My original point is that a Chart plotter is a luxury, but it is also becoming hard to avoid for example many radars now require an MFD which is also a plotter. I consider Radar much more important than a plotter for navigation and watchkeeping and AIS very important for monitoring traffic perhaps especially offshore where it only takes one ship to run you down and you are, perhaps, less likely to keeping a sharp lookout.

I'll stick by my original point that you should carry a handheld GPS as a backup to your main, if you rely on GPS for navigation, it's a much better and more reliable tool for the job.
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Old 25-06-2012, 17:03   #172
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Re: To Plot, or Not ? Is a Chart Plotter a Luxury or a Necessity ?

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Originally Posted by Littlechay View Post
A word of warning on the iPad and iPhone. As they are 'assisted GPS' devices their GPS will often not acquire a position offshore. If you want a backup it has to be a proper stand alone GPS.
No offense meant, but a word of warning on people who state things on CF that are wrong Really, when are people gonna stop repeating this fable?

If, and only if, your iPhone is older than the iPhone3gs (which is okay) you can have trouble with the internal GPS outside the phone networks.

An iPhone 4s will probably outperform most GPS systems. It uses both the American GPS and the Russian GLONASS satellites for extra precision. Here is an extract from AnandTech who analyzed the design and performance:

Quote:
MDM6610 inside the 4S inherits the same Qualcomm GNSS (Global Navigation Satellite System) Gen8 support, namely GPS and its Russian equivalent, GLONASS. The two can be used in conjunction at the same time and deliver a more reliable 3D fix onboad MDM6610, which is what the 4S does indeed appear to be using. GPS and GLONASS are functionally very similar, and combined support for GPS and GLONASS at the same time is something most modern receivers do now. There are even receivers which support the EUs standard, Galileo, though it isnt completed yet. This time around, Apple is being direct about its inclusion of GLONASS. The GPS inside MDM6610 fully supports standalone mode, and assisted mode from UMTS, GSM, OMA, and gpsOneXTRA.


cheers,
Nick.
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Old 25-06-2012, 17:13   #173
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Re: To Plot, or Not ? Is a Chart Plotter a Luxury or a Necessity ?

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An iPhone 4s will probably outperform most GPS systems. It uses both the American GPS and the Russian GLONASS satellites for extra precision.
Thanks Nick, I didn't know that about the 4s, perhaps the new iPads will work standalone too. I have an iPad 1 and and iPhone 4 and their GPS performance out of network range is crap to say the least.

But I note that even in your quote it says they they support assisted mode. Now given that position by cell and Wifi isn't that hot it seems strange they would bother with it at all.

Chris
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Old 25-06-2012, 17:27   #174
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Re: To Plot, or Not ? Is a Chart Plotter a Luxury or a Necessity ?

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Originally Posted by Littlechay View Post
Thanks Nick, I didn't know that about the 4s, perhaps the new iPads will work standalone too. I have an iPad 1 and and iPhone 4 and their GPS performance out of network range is crap to say the least.

But I note that even in your quote it says they they support assisted mode. Now given that position by cell and Wifi isn't that hot it seems strange they would bother with it at all.
iPad 1 got lousy GPS alright... because there is no GPS chip in it So that makes sense. Your iPhone 4 is doing alright, although it does show a little inconsistency with it's accuracy... but way good enough for boat navigation.

Apple decides to give something extra in the form of assisted mode... why not like that? The reason they do it is because satellite signals can't always be received, like when you're inside many buildings. A regular GPS looses fix where the iPhone/iPad still work. True, not much use for that aboard a boat but there's also landlubber buying these

ciao!
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Old 25-06-2012, 17:29   #175
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Quote:
Originally Posted by Littlechay
Yes I am aware of the different models of iPad and iPhone and their relative limitations. I am also a telecommunications engineer and used to plan cell , and satellite, networks before I went sailing full-time. Whilst I don't profess to be an expert I know enough about this subject to be dangerous

Even though they have a GPS chip it uses the information from the cell network, wifi networks, and the internet, to help initialise the GPS. I can assure you that once a GPS iPad looses lock away from the networks it will often not regain lock, of if it does it can take hours to achieve a GPS lock.

I have seen this many times at sea. If you keep your iPad on and in view of the GPS satellites it can maintain lock out of range of cell networks but if it looses lock because; you have it switched off, the battery dies, or you have it down below on a metal boat, then you have a problem. The iPad and iPhone use the internet to download the ephemeris data for the GPS satellites and if the internet is not available they seem to be stuffed (again this will be most obvious if the unit has been switched off or away from internet access for some time).

I use my my iPad as an electronic library, and have iNavX on it, but mainly at sea I have tried to use it with GoSkyWatch to help identify a star that I am not sure of or something like that. That is how I discovered the problem, and I have been monitoring it with other phones and tablets since, they all suffer from the same issue.

A good handheld GPS will acquire a GPS signal from cold, in minutes at most, it much more rugged, can use AA batteries, can be waterproof, and is cheaper than an iPhone or iPad or similar. Have the correct tool in your toolbox and your job will be much easier.

Chris
Even if this is true which I believe it is not there are alternatives. I do not keep a sim card in my ipad3. It takes longer to acquire satellites, especially if you have moved a large distance with the ipad off but it will acquire.

Even if what you say is true an external gps like bad elf or xgps150 can be plugged into the ipad and in fact this is my setup for my ipad 1 that does not have 3g at all.
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Old 25-06-2012, 17:41   #176
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Re: To Plot, or Not ? Is a Chart Plotter a Luxury or a Necessity ?

Back on topic then, another way of looking at this question is to define the word 'luxury'.

Noun:The state of great comfort and extravagant living.

Now, I dont know about you guys but something that can be had for a few hundred quid on a boat that costs 10 times that at the very least, that makes life easier, safer, more enjoyable, etc. does not come under the above definition.

A hundred years ago, the ease and relative cheapness of modern paper charts would have been thought of as a luxury and many years before that, an acurate timepiece to help navigation would have been the height of 'luxury'.


Simple fact is, time has moved on. Remember 20 years ago when a mobile phone was a 'luxury'? Now kids have them! 30 years ago colour TV was still a luxury and if you wanted aircon in your car it had to be a Rolls Royce. Just the humble ships clock (which would have cost a small fortune in the 17th-18th centuries), chart plotters are no longer the expensive toy for the rich. My own chart plotter cost me 15 (GPS reciever
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Old 25-06-2012, 17:46   #177
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Quote:
Originally Posted by s/v Jedi

iPad 1 got lousy GPS alright... because there is no GPS chip in it So that makes sense. Your iPhone 4 is doing alright, although it does show a little inconsistency with it's accuracy... but way good enough for boat navigation.

Apple decides to give something extra in the form of assisted mode... why not like that? The reason they do it is because satellite signals can't always be received, like when you're inside many buildings. A regular GPS looses fix where the iPhone/iPad still work. True, not much use for that aboard a boat but there's also landlubber buying these

ciao!
Nick.
I wonder if Apple may have released progressively better versions of the iPad 1? I have an iPad 1 with a gps chip and I have no problems acquiring satts anytime anywhere with absolutely no connection to wifi or cell services. Could explain why some of us different experiences than others. My iPad works as well as a gps as my handheld Garmin.

Don
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Old 25-06-2012, 17:52   #178
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Re: To Plot, or Not ? Is a Chart Plotter a Luxury or a Necessity ?

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I wonder if Apple may have released progressively better versions of the iPad 1? I have an iPad 1 with a gps chip and I have no problems acquiring satts anytime anywhere with absolutely no connection to wifi or cell services. Could explain why some of us different experiences than others. My iPad works as well as a gps as my handheld Garmin.

Don
Ah, my bad... I just googled and found that there are iPad1's with 3G which is the module that also has the GPS chip. It might even have the compass too then.

ciao!
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Old 25-06-2012, 17:53   #179
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Re: To Plot, or Not ? Is a Chart Plotter a Luxury or a Necessity ?

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Originally Posted by s/v Jedi View Post
iPad 1 got lousy GPS alright... because there is no GPS chip in it So that makes sense. Your iPhone 4 is doing alright, although it does show a little inconsistency with it's accuracy... but way good enough for boat navigation.
The 3G iPad 1 model does have GPS

From apples iPad specs -
Location
Wi-Fi
Digital compass
Assisted GPS (Wi-Fi + 3G model)
Cellular (Wi-Fi + 3G model)

it's assisted because it uses cellular data and the internet to help it acquire, but it's GPS non the less

From Apples latest iPad specs -
Wi-Fi
Digital compass
Assisted GPS and GLONASS
Cellular


My biggest issue with using a phone or tablet as a backup is battery life. With a handheld GPS you keep it with a few AA batteries and you have days worth of power, waterproofing and general robustness. Sure the phones and tablets are great tools but as a backup not a good idea. When the excrement hits the turbine you'd be better off with a cheap handheld. My backup isn't so cheap I use a Garmin GPS 60csx which loads C-map charts.

I have used my iPad as a plotter, it's great at the saloon table to discuss tomorrows route, dream cruises, explain why we are leaving at 4am to catch the tide etc. I've even hooked up all the instruments over wifi etc... all good fun. I love the Weather4D app.
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Old 25-06-2012, 18:09   #180
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Re: To Plot, or Not ? Is a Chart Plotter a Luxury or a Necessity ?

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I disagree, you do not need a chart plotter offshore at all. Offshore a chart plotter is useless, especially a small one. Zoomed out it will show how slowly you are crossing your bit of ocean, zoomed it it will show you a little boat icon on a blank screen. They are power hungry and will scoff your batteries whilst giving you very little useful information.

Inshore is where a chart plotter is useful, IF, you are sailing in an area with accurate charts. You can and should always check pilotage on a paper chart because that can be used for traditional position fixing even if there are significant distortions, beware of just plotting a GPS position onto the charts as that is what the chart plotter is doing, same difference.
What is on a paper chart that would tell me any more info when I'm in the middle of an ocean?

I've only been on non-commercial boats in lakes with little traffic or hazards, and I've never used either a chart plotter or paper charts before. But, I'm biased toward technology, and seeing the amount of unorganized paper I have around my house, I just don't see the usefulness of paper charts (as long as the electronics work and have power). Are electronic chart plotters not detailed enough? Paper charts seem time consuming and complex to me when on a moving boat.

I should note that when I am hiking in the backcountry of some national park, I use paper maps. I'm sure they make some great GPS devices, but the digital maps aren't nearly as detailed as the paper map.

Do chartplotters need larger higher resolution OLED screens to compete with paper charts? Do the maps need more information? Where do you think things will be in 5 years?
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