Measurement id gives an uniue identification to each measurement configuration.Though measurement object (Frequency belong to which technology ) or reporting configuration(Criteria to report) can be same But meas id will be unique for each entry in meas config.
Consider suppose meas object for GSM : -1 , UTRAN-2
Consider different types of reporting config A1,A2,A3 conditions.
Meas id will be different for each set
meas id 1 ------ meas obj id - 1 ---reporting config id - 1
meas id 2 -------meas obj id 1 -----reporting config id - 2