A system according to one embodiment includes an automatic gain control circuit (210) configured to provide an amplifier gain value; a temperature sensing circuit (212) configured to provide a temperature; an antenna switching circuit (206, 302) configured to decouple an antenna (202) from the receiver during a noise figure calibra¬ tion interval; a signal power measurement circuit (304) configured to measure input power to the receiver; a noise figure estimation circuit (306) configured to estimate a receiver noise figure during the noise figure calibration interval based on an initial receiver noise variance, the temperature and the amplifier gain value, wherein the initial receiver noise variance is estimated based on the measured input power during the noise figure calibration interval; and a noise variance tracking circuit (308) configured to calculate updated estimates of the receiver noise variance, wherein the updated estimates are based on updates of the measured temperature and updates of the measured amplifier gain.
