doubts about voice turn by turn GPS

Discussion in 'iPhone' started by wreckshop, Jul 24, 2008.

  1. wreckshop macrumors 6502

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    #1
    There are two problems. First is that for whatever reason, the GPS sensor cannot track you fast enough when you are in a vehicle. Second is that it doesn't know which way you are facing, so the map isn't oriented in the direction you are going.

    I tried out a Samsung Instinct for 3 weeks, and Sprint Nav is a far superior GPS implementation. Not only does it know which direction you are facing, it has vehicle and pedestrian modes, and a 3D map, with voice turn by turn directions.

    I hope I will be proven wrong about voice nav, since I love my iphone, but I have my doubts :(
     
  2. StingerT125 macrumors 6502a

    StingerT125

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    #2
    Mine tracks me great while I am driving, very smooth response.

    The other application you mention sounds like a Nav application which is very different from the maps application on the iPhone.

    If it is allowed; a Nav application should work just as good on the iPhone.
     
  3. zainjetha macrumors 6502a

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    #3
    Would apple allow this on their SDK and would it be compatible or be able to access the neccessary drivers for the GPS card inside the iPhone. Sorry if this is a stupid question but i really dont kknow or have my doubbts if it will work.
     
  4. wreckshop thread starter macrumors 6502

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    #4
    Sprint Navigation could track my location within 10 feet. iphone's GPS can lag by more than half a block. This is in downtown San Francisco btw. Maybe there is some truth behind that Pogue guy when he said iphone's GPS antenna is too small?

    I'm inclined to believe there are no navigation apps because the sensor isn't capable of knowing which direction you are facing. Even if the sensor could track you fast enough in a vehicle it's useless unless the map is oriented in the direction you are heading. Perhaps that's why the SDK forbids turn by turn nav.
     
  5. zainjetha macrumors 6502a

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    #5
    I think the SDK will forbid it because maybe Apple are waiting to sneak it in for another update later on.. They need to spread their eggs over updates (the have to balance it so they can release updates every now and then and again without running out of ideas or bloody bugs to fix).. I mean remember the bloody iPod and Safari issue (using at same time on iPhone or iPod touch would cause crashing -- they probably put it that in intesnensionally so they would or could release a bug ficx in an update)...
     
  6. wronski macrumors 6502

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    #6
    It's allowed and companies are working on a navigation solution for iPhone. Not blocked by SDK, Apple has said it's allowed. I have used dedicated GPS units that don't know which direction you're going; the software can figure that out once you actually start moving. There's nothing wrong with the antenna either.
     
  7. marksman macrumors 603

    marksman

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    #7
    Do most GPS have compasses built in?

    That is the only way they would know what direction you are facing. I always assume direction is determined by which way you are moving, so I assume the iPhone is as capable of that as any other device.

    I also believe there are settings that limit the refresh rate of the GPS right now which is why you are seeing it not keep up. If that number can be adjusted, then you will see a more responsive output. Since Apple says there is only a matter of time before this happens, I suspect your concerns are not going to be big problems.
     
  8. StingerT125 macrumors 6502a

    StingerT125

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    #8
    Even on a Nav GPS unit the sensor doesn't know which way you are facing. It can only tell by when you move and it picks up the change in direction. The application using the GPS information needs to orient the direction of the map.

    There have been mentions in other threads that TomTom is developing an application and also that an Apple representive said that Pougue was incorrect.
     
  9. wreckshop thread starter macrumors 6502

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    #9
    I'm curious, how does voice turn by turn work if the device isn't aware of the direction you're pointing when it recalculates a route? When a route is recalculated, doesn't it need to know which way you're heading?

    I've never had any experiences with GPS nav systems that didn't know which way you were pointing.

    Samsung Instinct must have some sort of compass built in because it knows which way you are facing when you launch Sprint Navigation, without even moving. Your location is pinpointed on the map by an arrow which points up and the map is drawn accordingly.
     
  10. SHIFTLife macrumors 6502

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    #10
    BS. My 3G's GPS tracks me just fine with smooth motion, from 0 - 80mph.
     
  11. StingerT125 macrumors 6502a

    StingerT125

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    #11
    It knows where you are and where your destination is, so it calculates the route between those to points.

    It only knows the way you are moving because of the change of your position, it is always calculating form the signals it is receiving.
     
  12. wreckshop thread starter macrumors 6502

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    #12
    have you tried tracking yourself in an area that have a lot of tall buildings?
     
  13. cdd543 macrumors 6502

    cdd543

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    #13
    check out the news section regarding 2.1 update adding core location necessary for turn by turn. The device has a proper gps chip so it should be no problem.
     
  14. wreckshop thread starter macrumors 6502

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    #14
    what about when you're not moving? Isn't the route it originally calculates dependant on the direction you're facing? or does it recalulate your route once you start moving?

    For instance, say I'm parked on a 2 way street facing north, but my destination is several miles south. Since Sprint Nav knows which direction I'm pointed towards it will calculate a route which tells me to drive several blocks north, then make a U turn. Without knowing which direction you're pointed, the route you need to take may be very different than the one that was orginally calculated.
     
  15. StingerT125 macrumors 6502a

    StingerT125

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    #15
    It's all in the application. GPS doesn't know anything except your location is. The application you are using does all the calculations around which way you are moving, which way your where moving, where you are, and your destination.

    If the application was tracking which way you were moving it know what direction you were going. Again, it's all in the application that is using the GPS data.
     
  16. wronski macrumors 6502

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    #16
    I have a Mio GPS that does that. It very quickly recalculates as soon as you start moving because it does not have a compass. It's rarely more than a second wait or a nuisance.
     
  17. BobboZR2 macrumors regular

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    #17
    Wow, some of you guys should really read how GPS works. I'm seeing some really stupid questions being asked in here.
     
  18. TimothyB macrumors 6502a

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    #18
    Most GPS units will not know which way it's facing until you start moving. Like my Garmin Nuvi 350. It can take a minute to lock the signals sometimes, and it has an antenna you fold out, and when it does, until I start moving, it doesn't know where I'm facing.

    But based of the previous position and new positions, it can deduce the right direction. And I think it only does that in 3D view, while direct down it might keep the map north, so it's not distracting if it suddenly swings left and right (don't have it with me right now). So it's a good thing the top down google maps doesn't face the direction you are moving, and it's not designed to do that, if the north keeps changing, it's hard to to read the map. While a 3D view, it's mostly there to see turns coming up easier.

    Whatever app that does come out for iPhone, it will have features like a 3D view and aim in the direction you are moving. And maybe the app won't work unless it gets enough satellite locks, if it can control that type of thing. It's not always going to be perfect, even stand alone GPS units can have trouble getting signals in Cities like San Francisco due to tall buildings, or inside a building, etc. It's all software, all the hardware it needs is the gps.
     
  19. TimothyB macrumors 6502a

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    #19
    I can't see how that would work well, does it have some built in compass to know where the unit is facing? Are you sure the unit didn't already figure out which direction you were facing based off recent movement in your location?

    What if you had your unit to the side of you in your car, instead of on the dash, with it facing to the door, would it think that's the direction? Wouldn't it just calculate the best route from the your current location and if some how you couldn't make a u-turn for a while, it would either know that already or recalculate again the moment you start moving?

    Is this Sprint Nav a cell? All I'm saying is, with such little devices, they might not always be pointing exactly the direction your car is, so it could easily make the wrong assumption and not really know which direction your car is facing. While with my Nuvi, if I had it on and then parked, it would already know which way my car is facing no matter which direction the unit is facing based on my movement from before.
     
  20. Small White Car macrumors G4

    Small White Car

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    #20
    Indeed.

    The iPhone GPS works the same as any other. (It may not be quite as accurate as others, but that's a different issue.) Other than accuracy, any other differences are purely software-based.
     
  21. donmei macrumors regular

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    Mar 8, 2007
    #21
    No gps knows what direction you are facing. It knows what direction you are MOVING.

    Back to the original post. There are 2 ways to display the mapping.

    1) track up - this means that you always appear to be moving forward. As you turn, the map on your device turns. This is how modern "idiotproof" car navigators work.

    2) North Up - the map is always oriented north up. As you turn, the icon representing you turns on the stationary map. This is how more sophisticated navigators work. It is also how the google maps for mobile on the iphone and blackberry work.

    Personally, I woldnt have it any way other than North up.

    Like someone else said. GPS only provides position info. once every second. Your device calculates direction of travel and speed based on the change in position over time.

    Like I said above, the refresh rate of GPS is 1 hz, I dont actually know how often the iphone updates. It is common for gps navigators to only update once every 2 or3 seconds when set in power saving mode.


    Don
     
  22. Van Wildonher macrumors 6502a

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    #22
    Uhh, sounds like your problem right there. :rolleyes:
     
  23. pj rage macrumors 6502

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    #23
    My older magellan GPS figures out direction by analzying your movement only. For your scenario, it just says for the first direction "head south on XXX road." If you don't know which way south is, and you are too stupid to figure it out by looking at the map, it will recalculate the route soon after you head in the wrong direction.

    I thought they all did it this way. I suppose a device could use a few sensors in combination to estimate it's pose and gather some heading data without moving. Not sure how accurate and reliable it would be, though.

    FWIW, my gps on my iphone appears to update my position every 2-3 seconds (and doesn't seem to be the same interval exactly every time). It is definitely NOT "smooth" as in 10 updates a second or so, or even the full 1 second updates it can get from the GPS. For reference, my magellan is always 1 second updates, consistently.

    I attributed it to the software implementation. I doubt it's a limitation of the GPS chip or any other hardware related problem.
     
  24. wreckshop thread starter macrumors 6502

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    #24
    I dont know exactly how it does it, but it somehow is smart enough to figure out which way the phone is pointed. I tested it in my apartment which is on a corner. It doesn't get it right all the time, but it was right enough times to lead me to believe that its not simply guessing. I mean if you think about it, what's the point of having an arrow instead of a dot if the arrow doesnt point the right way?

    I've never tried that, but I managed to confuse it a couple times. I was walking down a sidewalk and launched Sprint Nav, and just to see if it really could detect which way the phone was pointing, I turned it upside down - the opposite direction I was walking. After a couple updates, the arrow showed correctly which way the phone was pointing even though I was walking in the opposite direction. I think somehow that really confused it because when I turned it back rightside up, the arrow was stuck in the wrong position.

    Sprint Navigation is the navigation app that comes with the Samsung Instinct. It's powered by TeleNav and has turn by turn voice navigation which actually says each street name. All the map and voice data are stored server side so it can take up to 10 seconds to calculate a route. That's why I think this type of navigation app needs to know which direction you're facing so it can correctly calculate your route on the first try. otherwise when you're moving you might get stuck in a loop of recalculations.

    Sidenote: Even though iphone is easily superior to Instinct, Sprint Nagvigation is top notch. I was amazed at all the functionality it had for being on a cell phone. Now if someone can get all the functionality of Sprint Nav and somehow combine it with google maps, that would be the ultimate killer app.
     
  25. pj rage macrumors 6502

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    Jul 15, 2008
    #25
    From what I recall, telenav will be the first to iphone with their turn-by-turn gps app. I think I remember hearing mid/late august.

    We'll see, though.
     

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