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

Bi-monthly release with minor bug fixes and improvements

Tight time sync between devices?

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Hi all,
Does yet exist some work on tight time synchronization between remote servers/client? I need less than one ms synchronization between two mounts w/ cameras placed on different places and connected from a remote client.

Thanks in advance,
Ilia.
7 years 1 month ago #14749

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This is not entirely clear. Perhaps elaborate more. You want two remote mount drivers to have same time when they start up? If that's the case, then both need to have a GPS module to sync to with that accuracy.
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7 years 1 month ago #14751

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... or both of them need to run NTP server.
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7 years 1 month ago #14754

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Thanks for the replies.

An NTP server is a good idea, but it's not as much precise (PTP is its evolution in this manner). I need a method for precise timestamping of Camera/Telescope events like slew/Capture, scheduling captures for example. PTP (which could be implemented into a raspberry and a GPS) or something similar is like that I was looking for. For example a Ping-style word for hard-locking the client with the servers. Can this be done using the INDI protocol?
My goal is to build a new type of interferometer. It's basically simple as concept and needs synchronizing the capture mounts/cameras.
Last edit: 7 years 1 month ago by Ilia.
7 years 1 month ago #14755

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As the matter of fact you can use NTP and GPS to retrieve PPS signal, which get you to nanosecond precision.
I have been using such a setup on my Raspberry Pi for a while. The latest kernel does support kernel-mode PPS so you don't need to recompile. Depending on your distro you might need to recompile NTP server due to some releases are compiled without shared memory PPS support.
Take a look at this link to set it up.

BTW. I believe precise time synchronization should be provided by OS (kernel level) and not INDI. It is hardly possible to manage it outside of kernel space due to inherent delays related to system resource management in the user space.
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Last edit: 7 years 1 month ago by Radek Kaczorek.
7 years 1 month ago #14760

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Thank you very much!

I'll check this link, I've seen a similar system in past (one month ago ..).
This is exacly what I was searching for, but I forgot it! My memory's got corrupted XD
7 years 1 month ago #14761

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