Solar cells built into your phone…(the end of GPS units in 5 yrs?)

[Nick Larsen]

Well, as with all new technology it take a while to actually implement, but from this article, it looks like our cell phone power issues could be solved sometime before we die.

Solar cells built into the display of your cell phone would allow you to use your phone as your GPS unit, music, etc. while backpacking without the need of extra batteries or solar chargers! I'm thuper exthited!

See article here: http://spectrum.ieee.org/consumer-electronics/portable-devices/solar-cells-in-smartphone-screens/?utm_source=techalert&utm_medium=email&utm_campaign=01191

[Bob Gross]

"real soon"

Undefined. Maybe a decade.

–B.G.–

[Ben F]

People still use non-phone GPS units? Weird.

[Bob Gross]

Sure.

Find me a cell phone that can accept an external GPS antenna.

–B.G.–

[Ben F]

I'm pretty sure there are bluetooth external antennas that have worked since the Windows Mobile 5 days.

Edit: http://www.amazon.com/BT-359C-Globalsat-Bluetooth-GPS-Receiver/dp/B000GWGHOK

[Bob Gross]

That sounds like an additional place that will require another battery.

–B.G.–

[Nick Larsen]

@ Bob: That's why I said 5yrs, but you're probably right in that 10yrs is more likely. It takes a while to see what's being discovered today, actually implemented in consumer products. Funny how almost all of our "cutting edge" technology is actually up to a decade old.

[Dustin Short]

Nick, actually it's usually 30 years for technology to make it out of R&D and into "cutting edge." In fact the "30 year rule" is pretty common amongst a lot R&D engineers, especially electronics.

If you really wanted to make a lot of money it would be wise to grab a bunch of pop sci type magazines from the early 80s and see which technologies are ready to commercialize!

[Nick Larsen]

Really 30 years?! Geeze, I gotta quick getting IEEE stuff. I'll be dead before I see any of the cool stuff they write about.

[Bob Gross]

Ben F, I guess you noticed that the product link is not to an external GPS antenna. It is a GPS receiver with its internal antenna.

–B.G.–

[David Thomas]

Bob:

So this beastie:

http://www.sportys.com/PilotShop/product/16428

would also be an external GPS receiver with its own internal antenna?

Do you want an external antenna for greater sensitivity? Other than redundant circuits (hence weight), is there a drawback to these external, GPS+antenna units?

[Bob Gross]

Yes, your beastie GPS unit is a similar receiver with its internal antenna. The difference between this and a complete GPS receiver is that the complete one has its own display, which makes up a lot of the weight, and the complete one has all of its own software to manipulate the GPS position data into something useful to the user, like putting your spot on a map and scrolling the map. The incomplete receivers output a data stream of the current position, and that is all. They leave the software manipulation, maps, or whatever, for the rest of your system which is often a smart cell phone, iPad, or whatever. In many composite solutions like this, you end up with a battery inside this and a battery inside that and a battery inside something else. Nearly all of these small modules have their own internal patch antenna. Those will work OK for the average user, but they are not the sharpest tool in the shed.

I've dealt with maybe eight or nine thousand GPS receivers, each with an external antenna. It seems like the reason might be for greater sensitivity, but it isn't exactly. The typical signal strength hitting the earth's surface is good enough to be received adequately in 99% of all GPS receivers. Part of the problem is that maybe you don't want to have the antenna directly at the main receiver module. The typical example is inside a car. A typical driver can only focus his vision on a GPS display at a certain number of inches away from his eyeballs. If the display is sitting up high on the dashboard, then this doesn't work so good. If the antenna is up high on the dashboard, then the antenna can "look" straight up through the windshield and "see" the satellite signals. But if the display needs to be closer to the eyes of the driver, then the antenna and display need to be separated by a foot or two and then connected by some communication path which could be the actual GPS signals on a coaxial cable, the GPS position data on a data cable, the GPS position data on a bluetooth signal, or something equivalent. If you use the coaxial cable solution, then the GPS receiver feeds a tiny amount of DC power up the cable to power the low noise amplifier inside the antenna module, and then the amplified 1.57 GHz signal comes down the cable to the receiver. Each other solution has a different powering scheme. If you do not put the antenna in an optimal position, then maybe it will still work, and maybe not so good. If the antenna is directly underneath the metal roof of a typical car, it has to try to catch signals bouncing in through the glass windows, and this reduces accuracy or else halts dependable reception altogether. Yes, you get a little better sensitivity with an external antenna.

I've dealt with antennas that were up to 800 feet from the receiver. It's all good engineering fun.

When doing a winter climb one time, I put my GPS receiver inside my parka inner pocket to keep the display warm. Then I ran a coaxial cable up through the parka neck and into my hat. Between the inner and outer hats, I had an external antenna. This kept the antenna in a good position for reception, but it kept the receiver display in a good position for warmth and viewing. It aided my navigation in a white-out (this was on Mount Washington, NH).

I am one of those individuals who powers up his cell phone about once every three months. I use one complete Garmin receiver in my car, and I carry one tiny complete Garmin receiver on the backpack trail, despite seldom turning it on.

–B.G.–

[Jason G]

cell phone gps's are quite powererful nowadays. you really should check them out bob

[Bob Gross]

Jason, I am quite aware of those smart phone GPS systems. They seem to be marketed with the intention of getting you to buy more and more map data. There were some interesting facts flying by in that video, but you have to watch closely to see them. The plus or minus 98 feet accuracy in one screen is enough to choke on.

I don't see the power except for the marketing power behind it.

–B.G.–

[David Thomas]

Bob, Thanks for the explanation. I know pilot's panel-mount GPSs have remote antennas. But, with the costs of hurdles of certificated avionics, many just use a hand-held GPS velcro'd onto the panel. Especially up here. It meets the regs, but seems, well, sub-optimal.

[Mike W]

…

[Walter Carrington]

"When doing a winter climb one time, I put my GPS receiver inside my parka inner pocket to keep the display warm. Then I ran a coaxial cable up through the parka neck and into my hat. Between the inner and outer hats, I had an external antenna." –Bob G.

I think we need a cartoon of that :} Actually, it's a smart idea, though I don't think I'd want to carry a large antenna on my head on Mt. Wash. in winter.

[Bob Gross]

"Actually, it's a smart idea, though I don't think I'd want to carry a large antenna on my head on Mt. Wash. in winter."

The external patch antenna that I used there was about one inch square, and the length of coaxial cable was maybe 3mm diameter. The antenna was between the layers of my caps, so it did not get in my way, and it was nearly always pointed upward.

The alternative is to use your handheld GPS receiver (or smart phone GPS) and keep holding the thing out in front of you. In winter when you are using poles, that is not very practical.

Since I had never been up Mount Washington before, and since I had read all of the stories with a bad outcome, I wanted to be able to go up, hit the summit, and then make it back down with all of my toes intact.

When I climbed a different peak a few years earlier, I used a quad helix antenna.

–B.G.–

[Rakesh Malik]

"I'm thinking not.

What I hate most about the smart phones (aside from battery life) is that they are fragile and not waterproof. "

They're designed to force you into buying a new one, not to last.

Another thing I hate about them is that their GPS functionality relies heavily on triangulating the signals from cell towers. Since their built in GPS receivers are basically crap and their antennas tiny, the tradeoff for not burning up the battery so that cell users can continue tweeting, they do an abysmal job of actually identifying your location when you're doing things like moving.

In Seattle, I've seen the phone's claimed GPS accuracy vary wildly as I went in and out of the cell shadow of the buildings around, and in the back country it was usually a waste. It was very obvious that cellular GPS is designed largely for urban bozos wandering the streets, and not for people using them for driving directions or in the back country, and their primary effort toward the latter two has been marketing rather than actual product development.

Not that this should come as any surprise, since the leaders in cell phones these days are basically Gen-Ys whose idea of "wilderness" is Discovery Park.

[Bob Gross]

"Another thing I hate about them is that their GPS functionality relies heavily on triangulating the signals from cell towers."

That's true, but some of them depend more on cell-assist for GPS than others. Obviously when you get far enough out into the wilderness, there aren't any cell towers (or else there shouldn't be any). Then when that assistance is gone, all you have is the raw GPS receiver in the smart phone, which tends to be crappy, slow, or inaccurate (because they were optimized for cheapness using cell-assist).

Further, cell-assisted accuracy coming from cell towers is using precision timing at the cell towers, and that is generally crappy. That is because the cellular phone companies consider precision timing to be an overhead cost, so they invest as thinly as possible. If they could sell cell-assisted accuracy as a service, then they might make it better.

There are ways to get very high accuracy in a GPS receiver, but very few want to pay for it.

–B.G.–

[Roger Caffin]

> Not that this should come as any surprise, since the leaders in cell phones these days
> are basically Gen-Ys whose idea of "wilderness" is Discovery Park.
Who explore it via virtual reality on TV.

Cheers

[Rakesh Malik]

"There are ways to get very high accuracy in a GPS receiver, but very few want to pay for it."

As long as cell phones provide reasonable accuracy in urban settings, that's not likely to change. I've found that even with cell signal, my cellular GPS devices have been pretty bad, in that they can't tell whether you're on I-90 or on a service road parallel to I-90, even when that service road is close to 100 yards away.

Either way, I think it's pretty certain that smart-ass phone aren't going to replace dedicated GPS devices any time soon.

[Rakesh Malik]

"Who explore it via virtual reality on TV."

You got that right — especially in the Fat Country. I mean, the US. ;)

[Bob Gross]

"I've found that even with cell signal, my cellular GPS devices have been pretty bad, in that they can't tell whether you're on I-90 or on a service road parallel to I-90, even when that service road is close to 100 yards away."

Don't be too quick to indict the cellular GPS. It might have a fairly accurate position fixed, but the underlying map database in the device might be askew, or there might be a datum error.

I know some areas where the map database is consistently 80 yards off in one consistent direction. In other areas, the map database is almost perfect on a daily basis.

Due to the different timing technologies used by different cellular carriers, the errors can be all over the place.

–B.G.–

[Rakesh Malik]

"Due to the different timing technologies used by different cellular carriers, the errors can be all over the place."

Either way, the end result is that GPS in a cell phone is at best, mediocre.

The end result, regardless of where the problems lie, is that I can't trust a GPS in a cell phone to give me accurate information, no matter the cause of the error.

I seriously doubt that they'll ever get it together, since most of the cellular providers are more interested in buying politicians than improving their services and infrastructure, so the quality of their lousy service isn't likely to improve.

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