Adding a timestamp to my output

Hi I am working on a project where I am reading my location based on nearby beacons. This requires a timestamp too. The location is to be detected once every 30 seconds and then the data along with the timestamp is to be sent to the gateway and then the whole module will go to sleep mode for next 1 minute. After 1 minute again the module wakes up, detects its location and the process repeats. I need to add a timestamp to this project. The location tracking is being done using BLE devices. Is there any way that I can add a timestamp to the location data without using RTC? Thank you.

Your project needs to be able to retrieve the current time from somewhere, in the same way you look at the clock to see the time. RTC would be the easiest, but if you have wifi access you could do it that way too.

Thank you No, the main module doesnt have any wifi or ethernet, but my gateway does use internet connection which is connected to the main module used for location tracking, but via bluetooth connection. Can the timestamp be added?

The main module could just request the time from the gateway over bluetooth. Have a look here http://playground.arduino.cc/Code/time