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Was this a mistake? :D

I don’t have a CarPlay enabled car so couldn’t tell you, sorry.
Oh, I thought it was you who had indicated that CarPlay taps into vehicle systems rather than relying on its own entirely.
 
I’ll check on my way home today but I’m pretty sure it’s the iPhone GPS.

I'm seeing weird behavior in apps using GPS location when I use CarPlay. The current location is getting switched between the actual current location I'm in and somewhere in the middle of the sea near Thailand all the time.
Same thing happens with Google maps, Apple maps and even when I open Find iPhone app.
 
It may use either. Using the car's GPS is an optional part of the protocol for the manufacturer. One way to check is to use GPSdiagnostic app and check the accuracy as you plug and unplug it. It should get significantly more accurate when using the car's antenna.
 
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When you use Apple CarPlay its using your iPhone maps only. you can prove this by going to your iPhone and switch to iTunes and CarPlay will follow what you are doing. My Alpine ILX-107 has an External Antenna that is mounted on the Dash that it uses.
 
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I didn’t have time to find them earlier but these three WWDC sessions will tell you everything you want to know (and lots you didn’t, I’m sure) about CarPlay integration.

https://developer.apple.com/videos/play/wwdc2016/722
https://developer.apple.com/videos/play/wwdc2016/723
https://developer.apple.com/videos/play/wwdc2017/717

the first one in particular has this slide. GPS information is recommended as part of the standard for wired CarPlay systems but required for Wireless CarPlay because the phone is more likely to be out of sight (in a pocket or bag), have no GPS reception (again pocket/bag) and presumably the power drain figures in there too, though they don’t mention that.


F15286C2-B263-4D35-B80C-FE5E5D825F1A.jpeg
 
I didn’t have time to find them earlier but these three WWDC sessions will tell you everything you want to know (and lots you didn’t, I’m sure) about CarPlay integration.

https://developer.apple.com/videos/play/wwdc2016/722
https://developer.apple.com/videos/play/wwdc2016/723
https://developer.apple.com/videos/play/wwdc2017/717

the first one in particular has this slide. GPS information is recommended as part of the standard for wired CarPlay systems but required for Wireless CarPlay because the phone is more likely to be out of sight (in a pocket or bag), have no GPS reception (again pocket/bag) and presumably the power drain figures in there too, though they don’t mention that.


View attachment 789390
Looks like this is a big reason why very few car manufacturers support wireless CarPlay in their cars that support CarPlay.
 
Looks like this is a big reason why very few car manufacturers support wireless CarPlay in their cars that support CarPlay.

Could be, but GPS units are quite common in cars that don’t have Nav specified at this point. Cheaper to streamline the manufacturing line, building fewer SKUs, than the few bucks that GPS hardware costs. I tend to think that that car manufacturers are just very slow and very bad at software on the whole.

I wouldn’t put anything more than a few bucks on my theory over yours though. The car industry is pretty strange.
 
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Could be, but GPS units are quite common in cars that don’t have Nav specified at this point. Cheaper to streamline the manufacturing line, building fewer SKUs, than the few bucks that GPS hardware costs. I tend to think that that car manufacturers are just very slow and very bad at software on the whole.

I wouldn’t put anything more than a few bucks on my theory over yours though. The car industry is pretty strange.

As someone who has worked for over 2 decades in the auto industry, mostly at a manufacturer, you are correct - to a point. Much of the “strangeness” is due to the incredibly long (compared to other products) design and engineering cycle. Cars that will go on sale in 2022 are already nearing the end of their initial design phase. It’s very hard with those kind of lead times to accurately gauge what will be needed to interface with handheld devices at that point. Will there even be handheld devices then? I suspect Apple and Samsung do provide them with a limited product roadmap, but it may not account for everything the automakers need to know. And I know,from communicating with software engineers at the auto company that they can be just as puzzled as we are about why some things work and some don’t. A good case in point is the auto play feature that starts playing music without user input. They hate that.
 
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I'm seeing weird behavior in apps using GPS location when I use CarPlay. The current location is getting switched between the actual current location I'm in and somewhere in the middle of the sea near Thailand all the time.
Same thing happens with Google maps, Apple maps and even when I open Find iPhone app.
Would you happen to drive a Mazda? There's an issue with several models where it gives Android Auto a location halfway around the world, and I was wondering if it also happened with CarPlay. See here for more info and possibly a workaround: https://www.reddit.com/r/mazda/comments/9quqxm/official_android_autocarplay_anyone_getting/
 
I have a 2017 Honda Accord with nav. Sometimes, when I first start driving the car, its navigation is incorrect and may need a couple of miles driving to correct itslef. If I switch to the Apple maps in CarPlay, the navigation is always right on, even when the car's navigation is incorrect. So in my case, CarPlay is using the iPhone's GPS.
 
Mine and all have have used use the car's. Here is a way to test:

You can test and see GPS yourself:
  1. Drive due North (or any direction) with CarPlay/Apple Maps
  2. Stop car and put in Park, notice Triangle pointing North
  3. Unplug iPhone and open Apple Maps on iPhone
  4. Get out of car and walk 20 paces due West, notice Triangle pointing due West
  5. Turn and walk back to car, notice Triangle pointing due East
  6. Get in and as you plug in Triangle will still be pointing due East on iPhone screen
  7. When CarPlay screen comes on it MAY (mine does) still be pointing due East
  8. Within a second or 2 it will connect back to the car’s GPS/position and point due North
No matter what orientation your iPhone was or is in when you plug in if it “locks” back to your car’s GPS position then it is using the car's.
 
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It uses both. The phones GPS is augmented by the stereos GPS. You'll find stereos without built in nav also come with a GPS antenna just for this purpose.
 
It uses both. The phones GPS is augmented by the stereos GPS. You'll find stereos without built in nav also come with a GPS antenna just for this purpose.

No, I think it's not true. I bought RDC 330G plus for VW polo and it doesn't have any antenna.
[doublepost=1552447418][/doublepost]I'm having similar problem. Arrow keeps moving even after Car is stopped, most of time arrow is delayed. Arrow will move some other direction and then map will start re-routing. Very frustrating, already tried two iPhone X and SE, same issue. Iphone SE seems better but arrow lost twice in 30 mins drive. Problem is with Google, apple and Waze as well. But phone alone works perfect when phone not connected to dashboard car play.
 
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