chrony also uses the NTP protocol, and is also designed to make Linux clock more accurate. It is also suitable for systems that do not have an Internet connection. Then the source of the exact time can be any accurate clock, from which we can read the time and type it to the program. In addition, it is also capable of calculating the inaccuracy of the hardware clock, and based on that, adjust the hardware clock at boot time.
chrony 1.20 does not support built-in hardware clocks like GPS and DCF receivers, but the structure of the program makes such development possible.
chrony consists of two parts: chronyd daemon and a user interface chronyc.
You can find chrony at chrony.sunsite.dk/index.php