Method for the measurement of temperatures by microwave radiometry, with automatic calibration of the measurement, and device for operating this method

Device for carrying out a method for the measurement of temperature of a region by collecting through sampling during an acquisition period, by means of a detector, the thermal noise microwaves emitted by said region and by using a microwave short circuit, said method further consisting in collecting by sampling during an acquisition period the thermal noise microwaves generated from at least two internal temperature reference sources so as to generate from said emitted or generated thermal noises microwaves at least four resulting signals in order to determine a response indicating the temperature of said region in the absence of interfering influences produced by thermal derivatives or variations of the reflection coefficient of the detector with respect to said region, wherein said device comprises:

• a microwave detector, a microwave short-circuit, a modulator, called below first modulator, with two connected input channels, one at the output of the detector and the other, at the microwave short-circuit and an output connectable to one or other of the two inputs, a circulator with three successive channels, the first one being connected to the output from the first modulator, the second one to the input of a microwave electronic processing unit and the third one constituting a reference input, said device comprising in addition at least two internal temperature reference sources and a second modulator with at least two input channels each connected to the output from said at least two references sources and an output connected to said third reference input of the circulator, possibly through an attenuator, said electronic processing unit comprising:
• a synchronisation control circuit acting both on the first modulator and on the second modulator to obtain at least four different successive output signals, each of said at least four signals corresponding to each of the at least four possibilities of connection of the two modulators, the first one to two input channels and the second one to at least two input channels;
• a microwave detector with one input connected, advantageously through a microwave amplifier, to the output of the circulator and one output;
• and
• a computer means connected to the output of said detector and adapted to process, under the control of said synchronisation control circuit, said at least four successive signals detected to deduce therefrom the temperature at the level of the detector, independently of the reflection coefficient of the detector with respect to the region and to the losses of the modulators and of the cables.