[ntp:questions] [Android+NTP] synchronise time with millisecond accuracy

William Unruh unruh at invalid.ca
Wed Mar 26 15:55:51 UTC 2014

On 2014-03-26, Coiso22 <bcorreia.c at gmail.com> wrote:
> Hi all,
> I am trying to synchronise the time of an Android device with a local machine, for test purposes, using ntp. However, the difference between the time of the device and the ntp server is always around 5 milliseconds.
> Is there any way to synchronise the device with milliseconds accuracy?

That depends on how you connect between the two. Some connections simply
do not provide sufficient accuracy. What Android device? 

> Here is my test scenario configuration:
> Android Server:
> This is a machine running Debian that will be used as the ntp server and will send traffic to the Android device. This machine is connected with an Ethernet cable to have internet access
> Android AP:
> This machine is running Debian and acts as an Access Point. It is also connected to the Android Server with an Ethernet cable.
> Android Device:
> An Android device with root access. It is connected to the Android AP via WiFi. This device will receive the traffic generated by the Android Server, and must be synchronised with it.

Wifi is not a great connection medium. Especially wifi on some smart
Are you using broadcast from the server or real two way synchronisation?

And why for tax purposes would you need ms precision?

> Some notes:
> I do not need the Android Server to be synchronised with an external ntp server. Therefore, I changed the ntp.conf to have only "server".
> In order to synchronise the Android device I use the ntpd and have also tried with ntpclient. However, the results are very similar.
> Best regards

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