Device and method for calibrating a wideband radio frequency receive chain

1. A method of power calibrating of a wideband radio frequency receive chain configured to receive an input radio frequency signal from a receiving antenna, in a frequency band, the method implemented in a calibration device comprising the wideband radio frequency receive chain and a spectral analyzer, the wideband radio frequency receive chain including an input block connected at an input of a radio frequency processing assembly, the method comprising:

a first calibration phase of the input block, comprising, for at least one temperature value of the input block and a frequency, generating a given power spectral density of noise, using a noise source configured to be selected and controlled from the input block, and computing and storing at least one equivalent power spectral density of noise returned at an input of the input block; and

a second calibration phase of a power gain of the wideband radio frequency receive chain, comprising:

generating the given power spectral density of noise,

measuring a power spectral density of noise at an output of the wideband radio frequency receive chain, and

computing a power gain of the wideband radio frequency receive chain as a function of the power spectral density of noise at the output of the wideband radio frequency receive chain and the equivalent power spectral density of noise returned at the input of the input block corresponding to the given power spectral density of noise generated in the generating.

2. The method according to claim 1 , wherein, in the first calibration phase of the input block, the computation comprises:

obtaining a power gain of the input block for the temperature value and the frequency,

generating a noise having a given power spectral density of noise and measuring a power spectral density of noise at the output of the input block, and

computing an equivalent power spectral density of noise returned to the input of the input block as a function of the power gain of the input block and the power spectral density of noise at the output of the input block.

3. The method according to claim 1 , further comprising repeating the first calibration phase of the input block for a plurality of frequencies in the frequency band of the wideband radio frequency receive chain.

4. The method according to claim 1 , wherein the spectral analyzer is a processing module of the radio frequency processing assembly, and wherein the measurement of the power spectral density of noise at the output of the wideband radio frequency receive chain is obtained at the output of the processing module.

5. The method according to claim 1 , wherein the spectral analyzer is a calibrated auxiliary receiver comprising a spectral analyzer and the wideband radio frequency receive chain including an output block connected to an output of the radio frequency processing assembly, configured to switch between a first position for conveying the radio frequency signal toward a primary output of the wideband radio frequency receive chain and a second position for conveying the radio frequency signal toward an auxiliary output of the wideband radio frequency receive chain, on which the calibrated auxiliary receiver is connected during calibration,

the method further comprising a first phase for calibration of the output block, comprising computing a gain deviation between the primary output and the auxiliary output, for at least the frequency and the temperature value of the input block considered in the calibration of the input block, and, in the second phase, the computing of the power gain of the wideband radio frequency receive chain also accounting for the gain deviation introduced by the output block.

6. The method according to claim 1 , further comprising repeating the first calibration phase of the input block for a plurality of temperature values of the input block.

7. A device for power calibrating of a wideband radio frequency receive chain, comprising a wideband radio frequency receive chain configured to receive an input radio frequency signal from a receiving antenna, in a frequency band, the wideband radio frequency receive chain including an input block, a radio frequency processing assembly, and a spectral analyzer,

wherein the input block includes a noise source connected at an input of a switching member able to connect the noise source to an input of a block of downstream circuits of the input block, an output of the block of downstream circuits being connected at an input of the radio frequency processing assembly, the device configured to implement a calibration method comprising:

a first calibration phase of the input block, comprising, for at least one temperature value of the input block and a frequency, generating a given power spectral density of noise, using the noise source configured to be selected and controlled from the input block, and computing and storing at least one equivalent power spectral density of noise returned at an input of the input block; and

a second calibration phase of a power gain of the wideband radio frequency receive chain, comprising:

generating the given power spectral density of noise,

measuring a power spectral density of noise at an output of the wideband radio frequency receive chain, and

computing a power gain of the wideband radio frequency receive chain as a function of the power spectral density of noise at the output of the wideband radio frequency receive chain and the equivalent power spectral density of noise returned at the input of the input block corresponding to the given power spectral density of noise generated in the generating step.

8. The device according to claim 7 , wherein the wideband radio frequency receive chain has a specific background noise, and the power of the noise introduced by the noise source is greater than the power of the background noise specific to the wideband radio frequency receive chain.

9. The device according to claim 7 , wherein the switching member is a switch configured to switch between a first position for injecting the input radio frequency signal, in the block of downstream circuits of the input block, and a second injection position for injecting noise generated by the noise source in the block of downstream circuits of the input block.

10. The device according to claim 7 , wherein the noise source is a noise diode.

11. The device according to claim 7 , wherein the spectral analyzer is a processing module belonging to the radio frequency processing assembly, the measurement of the power spectral density of noise at the output of the wideband radio frequency receive chain being obtained at the output of the processing module.

12. The device according to claim 7 , further comprising an output block, connected to the output of the radio frequency processing assembly, comprising a switching member able to switch between a first position for conveying the radio frequency signal toward a primary output of the wideband radio frequency receive chain and a second position for conveying the radio frequency signal toward an auxiliary output of the wideband radio frequency receive chain, the spectral analyzer belonging to a calibrated auxiliary receiver connected, during the calibration, to the auxiliary output.

13. A radiogoniometry device comprising a plurality of wideband radio frequency receive chains, each connected to a receiving antenna, and a computation unit able to compute an angle of incidence of a radio frequency signal received by the receiving antennas, comprising, for each of the wideband radio frequency receive chains, a power calibration device according to claim 7 .