So...a couple of things. Firstly, "why" you need the PPS...
Let's back up a bit. In the ancient world of the 1970s and 1980s, when one spoke of "the system clock" or of a system's "clock", one did not mean the Time-of-Day Clock---what is nowadays called a Real Time Clock. The system clock was derived from a crystal oscillator ...
The HC12 is a very inexpensive, long-ish range serial transmitter that is pretty well suited to relaying GPS data at its normal rate of around one sentence a second. I have achieved well over 800m range with it.
There are some rough notes here, and plenty more around the Web for Arduino which you can adapt. It's actually cheap enough just to buy a couple and ...
I finally managed to somehow figure out the solution for it.
it was because of this serial-getty@ttyS0.service which was blocking any other data from ttyS0.
Just do the following:
sudo systemctl stop serial-getty@ttyS0.service
sudo systemctl disable serial-getty@ttyS0.service
and you are good to go.
NOTE: This is only tested for serial port(/dev/ttyS0) in ...
How much programming do you want to do? There will be some involved. Also, how pretty do you want it to be? The nicer displays look, the more work required.
Whatever you do, there are two main tasks:
get the number of satellites from the GPS
display that number on the e-ink screen.
1. get the number of satellites from the GPS
There are a couple of ways of ...
Rpi Thonny python IDE has a problem running a pynmea2 GPS program. How to fix it?
Part A - Troubleshooting notes
My Thonny is python 3, but your program is python2, so I need to format a bit:
(a) double quote to single quote,
(b) add colon after if statement.
Thonny then gave "import pynmea2" error, so I used Thonny package ...
I have some pigpio example code to generate a pulse per second.
It's some time since I have tested it.
It generates a pulse on the wall time second.
If the Pi is connected to a time source (i.e. it is networked) it will use that as wall time.
The DockerPi IoT Node may meet your needs. It includes GPS, GSM and LoRa functionality. You may also find The Things Network of interest which provides a LoRa Wide Area Network including a free to use Public Community Network.
It appears that your problem is that the modem and the GPS are detected in a random order on startup, yet you rely on automatically generated device names to tell them apart.
The second problem (which you resolved with a delay) is that your startup script sometimes runs before the devices are detected. The worst case detection time is theoretically very long....