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So I'm really new to Raspberry Pi (3), and want to track the device position. Therefore I ordered a GP 20u7 GPS receiver.

I connected it as shown below, set up the deamon (gpsd), configured the ttyS0, but no succes. I do have NMEA messages coming from /dev/ttyS0, but without values for lat and lon. See also the included figure for cgps.

So my guess is that I'm doing something very wrong. Do I need more hardware components to make this setup? I can't find a clear answer online. I thought the receiver would be enough...

Thanks for any advice!

enter image description here enter image description here

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  • What are the serial communication settings such as baud that you are using?
    – Richard Chambers
    Commented Mar 23, 2018 at 11:43
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    Also check that your physical connections are correct. See this SparkFun tutorial on Serial Communications with some basic troubleshooting. Also see SparkFun tutorial on GPS basics.
    – Richard Chambers
    Commented Mar 23, 2018 at 12:03
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    How long have you let it run? Getting a good fix and valid data can take up to several minutes, even with a good outdoor clear sky on some receivers.
    – SnakeDoc
    Commented Mar 23, 2018 at 18:17

2 Answers 2

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Have you tried it outdoor? GPS has very low to no reception indoors. Also you have to receive a signal from at least 4 GPS satellites. Smartphones overcome this issue by using the WiFi and cellular strength and a map service where each WiFi network and cell is mapped to GPS coordinates.

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    Smartphones do quite a bit more than just "map Wifi networks to GPS locations". The two main things they do is use the WiFi to download approximate GPS satellite orbits, and then use the coarse WiFi location to quicker locate each satellite. (You need both your own position and the satellites to determine whether it's above the horizon)
    – MSalters
    Commented Mar 23, 2018 at 15:18
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    Also, smartphones can use AGPS (uses the cellphone network to get a [more accurate] location).
    – Ismael Miguel
    Commented Mar 23, 2018 at 17:04
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If your setup matches the image -- I do not see how you can be getting NEMA sentences via ttyS0 -- you have the GPS transmit connected to the RPi UART transmit. It needs to be on the UART receive -- next pin.

Did you verify at the command prompt?

sudo cat /dev/ttyS0

Antennas are usually not necessary -- I get data without one.

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