[powerbooks]

I was surprised to find from the new Apple iPhone 3G tutorial video that the so called new GPS feature in iPhone 3G seems only operate manually. That is: you have to manually touch for the next turn when you are driving on the road in order to follow the direction and locate the right coordinate, and the map will not automatically change the screen and coordinates according to your position like the real GPS. As far as I remember, this "manual" GPS feature has already been in version FW 1.1.4 for iPhone classics. Am I missing something here?

[chabig]

I don't think so. The videos on Apple.com show the blue dot tracking your position. All you have to do is make it follow the blue line. Selecting the next button simply changes the map view and the text, I think.

[kman42]

I think you are both right. Your position is tracked (i.e. the blue dot moves as you move), but I didn't see any indication in the video or the keynote that the text instructions update automatically according to your current position.

[stevesnj]

yeh it wont guide you it just shows your current position when u move

[njuyhb]

So, if you're trying to use this for driving directions, will it be adequate? I currently have a verizon phone, and their vz navigator is quite nice for a cell phone. It will be a deal breaker for me if the iphone can't offer a similar level of navigation quality.

I know this won't speak out driving directions while you drive, but will it at least show your position along a route, so you can at least see visually when your next turn is coming up?

Also, will it's gps reception quality be at least as good as that as a typical verizon phone (such as an enV)?

[kman42]

One of the reviews that just came out (Mossberg's maybe?) reports that Apple told him that the GPS antenna is too small to allow turn-by-turn directions like you get in a dedicated GPS unit. Given the ability of other phones to do this, I'm thinking this is FUD and that Apple is working on their own solution that isn't ready yet.

[analogue SPRINKLES]

Originally Posted by kman42 

One of the reviews that just came out (Mossberg's maybe?) reports that Apple told him that the GPS antenna is too small to allow turn-by-turn directions like you get in a dedicated GPS unit. Given the ability of other phones to do this, I'm thinking this is FUD and that Apple is working on their own solution that isn't ready yet.

Ya I don't get that "Too small" thing either.

[Cold Warrior]

That doesn't make any sense. Antenna length is designed for the frequencies it needs to maximize gain for. GPS accuracy is determined differently.

[Randman]

I wouldn't be surprised if TomTom offers something on the app store that unlocks this feature. And maybe bundles it with a car mount.

[ort888]

Yeah, expect an app at some point.

[njuyhb]

Yeah, I read that thing about antenna length, and I don't get it.... if just about every verizon phone can do it, and that sprint thing, then there's no reason the iphone shouldn't be able to do it. But, it doesn't for some reason. I'm very leary about committing to a 2 year contract over the "possibility" that it may be able to do this in the future, unless what's already available on the iphone is good enough to get you to work when your normal route is closed.

[njuyhb]

Anything tom tom will offer will almost certainly require its own subscription.

[powerbooks]

Mentioned that there is no "turn to turn" direction, but still not clear whether it can at least refresh screen and coordinate automatically......

One of the comments over there also claims that Apple SDK specifically prohibits making this "turn to turn" function available to any program on iPhone. Who knows......

[njuyhb]

So, has anyone tried using this as a driving navigator? How well does it work as such? How good is the gps receiver in general? Can you get a signal, say, in your basement?

[ghporter]

Originally Posted by Cold Warrior 

That doesn't make any sense. Antenna length is designed for the frequencies it needs to maximize gain for. GPS accuracy is determined differently.

Some aspects of the antenna are specific to frequencies, but others are specific to something called "antenna gain." Basically, a flat patch GPS antenna will capture only a small amount of signal, while a more complex and thicker antenna will capture more signal. But I don't think that's what's going on.

I think it's a matter of how many satellites the unit can simultaneously track. The more satellites you can track at one time, the more smoothly the unit will track your movements. A minimum of four satellites (in the right positions in the sky) is required for lat/long/altitude tracking. The positions of the satellites must be sufficiently different for their data to be usable; if they're too close together, they won't provide sufficiently different data for the unit to resolve location, and if they're too close to straight overhead, their data will not be as useful because of the lower transit time.

Optimum tracking (with the current constellation of satellites) comes from tracking 12 satellites simultaneously, preferably through reception with an advanced, complex (and relatively thick) antenna.

[chabig]

The two GPS frequencies that the iPhone needs are called L1 and L2. L1 has a wavelength of 19.05 cm and L2 has a wavelength of 24.34 cm. Clearly, the antenna in the iPhone is too small to be of optimum length for these frequencies.

[stevesnj]

Originally Posted by Randman 

I wouldn't be surprised if TomTom offers something on the app store that unlocks this feature. And maybe bundles it with a car mount.

I want it for my motorcycle...i put off buying a stand alone GPS for it and going to wait to see how a GPS app works on the iPhone.

[Simon]

Originally Posted by chabig 

The two GPS frequencies that the iPhone needs are called L1 and L2. L1 has a wavelength of 19.05 cm and L2 has a wavelength of 24.34 cm. Clearly, the antenna in the iPhone is too small to be of optimum length for these frequencies.

If it were that simple a whole lot of antennas wouldn't work at all. Or does your battery powered analog radio come with a 3m long antenna? Are you familiar with lambda/2 and lambda/4 antennas?

[macmad]

GPS only works when you're moving. Satnavs like TomTom have an electronic compass in them, and factory fitted car satnavs additionaly receive vehicle speed and distance information. I don't think I'd trust an iPhone for anything too accurate.

[Kvasir]

Originally Posted by macmad 

GPS only works when you're moving. Satnavs like TomTom have an electronic compass in them, and factory fitted car satnavs additionaly receive vehicle speed and distance information. I don't think I'd trust an iPhone for anything too accurate.

Huh? what on earth does moving have to do with GPS? Moving or standing still, the GPS unit still gets the same information from the satellites to compute a position. My HTC phone's GPS certainly works just fine just standing still.

To the OP, it sounds like the iPhone is just using an adaptation of Google Maps for Nav. On my AT&T Tilt, when using Google Mobile Maps for navigation, it beeps and you must touch the screen for each new direction prompt. AT&T's re-branded version of Telenav, which I also use, does not do that - it uses true voice turn-by-turn directions wiht street names.

[macmad]

Originally Posted by Kvasir 

Huh? what on earth does moving have to do with GPS? Moving or standing still, the GPS unit still gets the same information from the satellites to compute a position. My HTC phone's GPS certainly works just fine just standing still.

You're right! I meant it can't tell what direction you're looking unless you're moving. If you turn around on the spot, your co-ordinates don't change, but the prospect around you does - you have to move, so the map can correctly orientate.