Thanks a lot @brocaar for your support. Does this mean that i can never get time field in nano seconds with my multitech conduits? 
As my work is related about implementation of TDoA, i would certainly need nano second accuracy.
Is there any way to achieve it with my current hardware?
Can we convert tmst filed data type (currently unsigned integer) to float data type? As float provides more precision. 
Thanks a lot for your support.