GPS HAT signal strength indoors

Moderators: adafruit_support_bill, adafruit

Forum rules
Talk about Adafruit Raspberry Pi® accessories! Please do not ask for Linux support, this is for Adafruit products only! For Raspberry Pi help please visit: http://www.raspberrypi.org/phpBB3/
Locked
User avatar
kshetline
 
Posts: 9
Joined: Wed Apr 01, 2020 3:00 pm

GPS HAT signal strength indoors

Post by kshetline »

I'm wondering why it's difficult to get good signal indoors with the Adafruit GPS HAT, even with an active GPS antenna, while at the same time, same location indoors, my iPhone gets a strong, clear signal, and doesn't need an external antenna attached to do it.

At least when I was in a south-facing bedroom I could get a decent signal with my active GPS antenna attached. Now that I in a north-facing room for the time being, even the active antenna doesn't help enough.

It's not like I'm deep inside a concrete-and-steel building. I'm just in an ordinary two-story wooden house that doesn't bother my iPhone's GPS reception in the least.

User avatar
sj_remington
 
Posts: 998
Joined: Mon Jul 27, 2020 4:51 pm

Re: GPS HAT signal strength indoors

Post by sj_remington »

GPS signals are very weak, and locating generally doesn't work well or at all indoors.

Since phones have multiple ways of determining your location, there is some reason to be skeptical of your claim. Please post a screenshot showing the actual iPhone satellite signal strength graph at the problem location. If you can do the same for the GPS HAT, a side by side comparison would be helpful.

User avatar
kshetline
 
Posts: 9
Joined: Wed Apr 01, 2020 3:00 pm

Re: GPS HAT signal strength indoors

Post by kshetline »

Here's my iPhone GPS signal, from a GPS diagnostics app that only shows GPS data, nothing from any other location service:

Image

Just this little snippet from gpspipe shows I can't even get a signal lock with my GPS HAT:

Code: Select all

{"class":"TPV","device":"/dev/serial0","mode":1,"time":"2022-09-11T18:24:59.010Z","ept":0.005}
When I stuck my antenna outside my window, and dragged the antenna block as far away from the house as the connecting cable would allow, I did finally get a signal lock, but, no, I don't want to run the wire outside my window and plant a pole in the ground to tie it to where I was standing and got a signal.

User avatar
kshetline
 
Posts: 9
Joined: Wed Apr 01, 2020 3:00 pm

Re: GPS HAT signal strength indoors

Post by kshetline »

I discovered how to send the NMEA command "$CDCMD,33,1*7C" to query my antenna status, and the response I'm getting is "$PCD,11,1 *66", which indicates that only the internal antenna is engaged.

It's a disappointment that the internal antenna isn't good enough by itself, nevertheless, this tells me that even although I thought my external antenna was connected, the GPS HAT doesn't agree.

On the chance that the pigtail connector for the external connector has failed, I've ordered a replacement to see if that helps.

Locked
Forum rules
Talk about Adafruit Raspberry Pi® accessories! Please do not ask for Linux support, this is for Adafruit products only! For Raspberry Pi help please visit: http://www.raspberrypi.org/phpBB3/

Return to “Adafruit Raspberry Pi® accessories”