Time stamping a sensor sample

Methods and devices for determining a timestamp that represents a time a sensor sample was generated are described. In one aspect, a method includes: obtaining a sampling rate estimate for the sensor; determining an expected sample time based on the sampling rate estimate; detecting a sensor sample and assigning a reporting time to the detected sensor sample, the reporting time representing the time when the sensor sample was detected; and determining the timestamp for the sensor sample based on the expected sample time and the reporting time.