Data clarification

Hi! Could you please clarify?
Why timestamp at “timeAtServer” is less then timestamp at sensors “measurements”?
I thought that signal from aircraft go to sensors (and here we have timestamp in “measurements”), then information about new entry go to server (and here we have timestamp in “timeAtServer”).


timeAtServer is a date in seconds from 0 to 3600 as we are working with one hour of data, 0 being the first entry in the file. I do not know exactly how this date is computed.

The timestamps are the dates (in nanoseconds) at which different receivers receive the same message. We do not have the date at which the aircraft has emitted the message.


@richardalligier, Thank you.

I understand, that timestamps in “measurements” are the time of arrival of the signal at the receivers (in nanoseconds).

According to the documentation, “timeAtServer” - is the time when the information was received by OpenSky’s ingestion server.

In data, sensors timestamps increases from ~0.9 sec, to ~3600,9 sec; timeAtServer is a time in seconds from 0 to ~3600 sec. So, I assumed that both indicates the same one hour. Is it correct?

So, the question is: if both timestamps of the same aircraft indicates time in the same hour, and server received data from sensors, why timestamp of receiving information about the aircraft by the server is less then timestamp of signal arriving at sensors (it is indicates, that information about signal arrive to server earlier than signal arrived to sensors) ?

@masorx could you please comments