It's the built in navigation. My car has issues all the time. I can drive an hour in the woods at 2mph it won't lock in. Pull in to a clearing and it starts working. Back under tree cover it wigs out. But the GPS system has good days and bad based on solar radiation too. My drones have issues somedays and they are above the tree cover.

 

That is not surprising, as under those conditions even my Garmin handheld mapping GPS has issues. Summer woods and conifer woods are the worst, winter with no leaves are much better.

 

CarPlay is just a remote screen for your phone. Only the built in nav in the car uses the antennas in the car. If it’s a map application on the phone, it’s your phone doing that.

 

carplay can use in car GPS antena ... its up to car (radio) manufacturers to supply GPS data to Carplay
the 3.1 units from 2019 till now (Forester) have GPS antenna on non NAV models..


i suspect it still used in 11.6 also as your default storage of cell phone is in cubby under the radio with worst possible gps signal

 

i find it very strange. with my previous car's Pioneer head unit, CarPlay deferred to the antenna mounted on the dash that came with the head unit when i used Apple, Google, or Waze maps.

i will do some experimenting and just try out using the built in nav to see if it exhibits the same issues. (i'm having problems in locations i never hard previously in my prior car)

 

Your Impreza was no different. AFAIK, if you're running a nav app on your phone, whether Carplay is involved or not, then you're using the phone's internal GPS module and antenna.

 

Interesting. i don't have any way to refute or back up what you suggest. from what i understood, with my Pioneer NEX4500 deck, the "external antenna" was used by CarPlay or Android Auto (i didn't try the latter). this deck had no native navigation software.

if it's my phone's GPS, then i'm very puzzled about why it's not tracking well immediately after i start driving because it used to with my Impreza.

 

just did a web search and came up with the following:

https://www.pioneer.com.au/knowledge-hub/help-support/why-is-the-location-of-the-gps-antenna-important-for-pioneer-wireless-av-receivers/#:~:text=The%20GPS%20antenna%20is%20highly,Apple%20CarPlay%20or%20Android%20Auto

.

"The GPS antenna is highly important for wireless Pioneer AV receivers as this assists the system in accurately locating position when using Apple CarPlay or Android Auto. "

it appears that the Pioneer was smart enough to use both the phone and this antenna if the text above is to be believed. on that same page, it does say that for Pioneer units with Nav, it will use that external antenna exclusively.

 

I don't know which antenna Subaru implements into the car, but both Android Auto and CarPlay implement the capability to receive a GPS signal from the car's antenna. It's not "just" a remote screen.

Someone could do a test with some aluminum foil.

 

Wireless CarPlay requires the GPS signal from the vehicle itself.
If you go to around 12:54 of the video, you can see what Apple requires in order for a vehicle to offer CarPlay - Developing CarPlay Systems, Part 1 - WWDC16 - Videos - Apple Developer