Abstract: The noise temperature of satellite navigation active receiving antenna is one of the key technical indexes of navigation receiver.In order to solve the problem that the overall noise temperature of the satellite navigation active antenna cannot be measured,two surface type noise sources are developed.The surface type noise source is mainly composed of radiator,radiator physical temperature control and temperature measurement instrument.The two surface type noise sources provide the high and low standard noise temperature in L band and S band.The noise temperature of active receiving antenna is measured by Y-Factor method.The noise temperature of a satellite navigation active antenna is measured.In the frequency range of (1.19~1.29) GHz,the noise temperature measurement result is 206 K at the center frequency of 1.24 GHz.However,the noise temperature measurement result is greater than 4 000 K at the frequency of 1.266 GHz,which indicates that there are design problems or other problems between the antenna and the filter,and between the filter and the amplifier,reflecting the necessity of measuring the noise temperature of the active antenna.

Key words: Noise temperature, Active antenna, Y factor, Surface type noise source, Global Navigation Satellite Systems (GNSS)