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INDI Library v2.0.6 is Released (02 Feb 2024)

Bi-monthly release with minor bug fixes and improvements

How to use smartphone GPS with INDI-GPSD

This is a separate driver for those who do not have a GPS dongle and want to use their mobile phone as the GPS. If you have GPS dongle, use GPSD.
The following user(s) said Thank You: Yannic Delisle
6 years 5 months ago #20439

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We talk to each other sometimes ;) But seriously... Kudos to Jasem for indi-gpsnmea driver. It fills the gap for people who use mobile phone's gps for setting location and time in KStars/Ekos. indi-gpsd does pretty much the same, however it is based on different approach. Both of the drivers set time and location (over INDI server) to other INDI drivers (e.g. mount) and clients (e.g. KStars), but:

indi-gpsnmea:
  • reads gps data stream from mobile phone's gps
  • requires network connection of the source of gps data stream i.e. phone running app, which enables gps sharing
  • does not set operating system time/date based on gps source
  • it is operating system independent

indi-gpsd:
  • reads gps data stream from gpsd service
  • requires gpsd service is running and properly configured as a systemwide service
  • ntpd service can read from gpsd service to synchronize operating system time/date to gps source
  • it is operating system dependent and can be used only on linux

There's no conflict between the two - NTP gets time from GPSD to set operating system time/date, not INDI drivers' and clients' time/date.
We can consider merging these drivers at some point in time, but for now you should run either indi-gpsnmea or indi-gpsd. Using both drivers at the same time makes no sense.
The following user(s) said Thank You: Jasem Mutlaq, Yannic Delisle
6 years 5 months ago #20442

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Great answer! It's now part of the documentation for both drivers to avoid any confusion in the future! Now it would be nice if the GPS NMEA driver can also set the system time, but due to escalated privileges required for this, it's not possible now unless it goes via another program that can set this without root.
The following user(s) said Thank You: Radek Kaczorek
6 years 5 months ago #20444

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Regarding setting Linux system time with GPS/NTP server, from my experience the NTP daemon will not sync the system time if it is too far off automatically. It considers the time to be in error. My solution is to run a python script to force the system time to sync with the NMEA source. NTP will then keep in sync. My script requires Sudo, perhaps it can be improved or a replacement integrated? Because if Kstars/INDI can keep my system clock set, that is one less thing to do when I power on a Raspberry Pi.
Time sync script:
import os
import sys
import time
from gps import *
 
print 'Attempting to access GPS time...'
 
try:
	gpsd = gps(mode=WATCH_ENABLE)
except:
	print 'No GPS connection present. TIME NOT SET.'
	sys.exit()
 
while True:
	gpsd.next()
	if gpsd.utc != None and gpsd.utc != '':
		gpstime = gpsd.utc[0:4] + gpsd.utc[5:7] + gpsd.utc[8:10] + ' ' + gpsd.utc[11:19]
		print 'Setting system time to GPS time...'
		os.system('sudo date -u --set="%s"' % gpstime)
		print 'System time set.'
		sys.exit()
	time.sleep(1)

It also requires configuration of ntp.conf with the addition of these lines.
server 127.127.28.0 minpoll 4
fudge  127.127.28.0 time1 0.183 refid NMEA
server 127.127.28.1 minpoll 4 prefer
fudge  127.127.28.1 refid PPS
6 years 5 months ago #20445

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I tried this driver today.

It will work fine without GPSD! !

But time was registered a little bit.

Tried environment
OrangePi 2 plus (WiFi AP mode)
ubuntu 16.04
iPad 2 (GPS model)
GPS 2 IP

I attach photos.
The following user(s) said Thank You: Jasem Mutlaq
6 years 5 months ago #20454
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Thanks for testing! The GPS NMEA driver does not change system not. At least not yet.
6 years 5 months ago #20455

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Yes, It does not use gpsd, Jasem wanted to avoid that. The phone's NMEA server communicates straight to the INDI driver. This of course means that currently the system time is not updated, just the time in KStars.
6 years 5 months ago #20456

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Connecting without using GPSD is a big improvement!
(Connection with smartphone is not complicated)

I did not have enough words.
A time offset is sent.
The ipad time is the same as the screen time on the upper right, but in my environment, it will be registered in about 5 minutes in another time.
6 years 5 months ago #20459

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Compare with the time part of the driver.
6 years 5 months ago #20461

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That is a correction.
It is time display of Kstars.

Several minutes have elapsed since setting the time from the driver.

When sending GPS transmission ipad, VNC remote OSX will display the same time, but the time of kstars synchronized with the driver and telescope driver will be registered about 5 minutes apart.
6 years 5 months ago #20462

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I tested it later.

As written earlier, different times are written to the driver. (Different about 5 minutes)

Latitude, longitude, and time information are not sent to the mount.

I am logging, so please check.
Last edit: 6 years 4 months ago by T-Studio.
6 years 4 months ago #20487

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I can not send a log file. .
Last edit: 6 years 4 months ago by T-Studio.
6 years 4 months ago #20488

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