Integrated AESA/radar in-situ calibration IP disclosure
A system for insitu AESA calibration includes a radar receiver/excitor (XR). The calibrated XR functions as a precision multi-channel relative amplitude and phase microwave frequency measurement device that executes a known AESA calibration methodology. An integrated RF sensor system-level built in test (BIT) is utilized for prognostic health monitoring and self-healing calibration. During calibration, quadrants of the AESA are iteratively calibrated via measurements by the XR. I/Q values are balanced for each quadrant relative to each other without the need for a separately calibrated measurement device for absolute calibration. A near field probe may be disposed for radiative loopback measurements. A T/R calibration circuit receives the loopback measurements and data from a Tx channel.
1 . A computer apparatus comprising:
at least one processor in data communication with an active electronically scanned array (AESA) and a memory storing processor executable code for configuring the at least one processor to:
receive digitized in-phase (I) and quadrature (Q) values for each of a plurality of receive channels, each associated with one of a plurality of subarrays of the AESA, generated via a radar receiver/excitor (XR);
determine relative amplitude and phase differences between the plurality of subarrays of the AESA using the digitized I/Q values;
balance the relative amplitudes and phases for each of the plurality of receive channels relative to each other; and
iteratively calibrate each subarray of the AESA by calculating specific amplitude and phase values for the corresponding subarray based on the digitized I/Q values, without a separately calibrated measuring device.
2 . The computer apparatus of claim 1 , further comprising a loopback circuit, wherein the at least one processor is further configured to determine a Tx and Rx level shift between each of the plurality of receive channels.
3 . The computer apparatus of claim 1 , wherein the at least one processor is further configured to:
drive at least one radiating element in a subarray of the AESA;
receive radiative loopback values via a near field probe from the subarray of the AESA; and
perform T/R calibration with respect to the radiative loopback values.
4 . The computer apparatus of claim 1 , wherein the at least one processor is further configured to balance a relative amplitude and phase for at least one transmit channel.
5 . The computer apparatus of claim 1 , wherein the at least one processor is further configured to use a first subarray as a sensor in subsequent calibration steps after the first subarray is calibrated.
6 . The computer apparatus of claim 1 , wherein the at least one processor is further configured to:
determine a mission phase; and
recalibrate the AESA according to the based on mission phase, changes to internal and external environmental effects, or on demand.
7 . A method comprising:
receiving digitized in-phase (I) and quadrature (Q) values for each of a plurality of receive channels, each associated with one of a plurality of subarrays of the active electronically scanned array (AESA), generated via a radar receiver/excitor (XR);
determining relative amplitude and phase differences between the plurality of subarrays of the AESA using the digitized I/Q values;
balancing the relative amplitudes and phases for each of the plurality of receive channels relative to each other; and
iteratively calibrating each subarray of the AESA by calculating specific amplitude and phase values for the corresponding subarray based on the digitized I/Q values, without a separately calibrated measuring device.
8 . The method of claim 7 , further comprising:
driving at least one radiating element in a subarray of the AESA;
receiving radiative loopback values via a near field probe from the subarray of the AESA; and
performing T/R calibration with respect to the radiative loopback values.
9 . The method of claim 7 , further comprising determining a Tx and Rx level shift between each of the plurality of receive channels.
10 . The method of claim 9 , further comprising performing I/Q level adjustment among each subarray of the AESA, relative to each other subarray of the AESA.
11 . The method of claim 7 , further comprising balancing a relative amplitude and phase for at least one transmit channel.
12 . The method of claim 7 , further comprising:
periodically monitoring AESA health metrics; and
recalibrating the AESA according to the AESA health metrics.
13 . A radar system comprising:
an active electronically scanned array (AESA);
a loopback circuit; and
at least one processor in data communication with the AESA and a memory storing processor executable code for configuring the at least one processor to:
receive digitized in-phase (I) and quadrature (Q) values for each of a plurality of receive channels, each associated with one of a plurality of subarrays of the AESA, generated via a radar receiver/excitor (XR);
determine relative amplitude and phase differences between the plurality of subarrays of the AESA using the digitized I/Q values;
balance the relative amplitudes and phases for each of the plurality of receive channels relative to each other; and
iteratively calibrate each subarray of the AESA by calculating specific amplitude and phase values for the corresponding subarray based on the digitized I/Q values, without a separately calibrated measuring device.
14 . The radar system of claim 13 , wherein the at least one processor is further configured to:
drive at least one radiating element in a subarray of the AESA;
receive radiative loopback values via a near field probe from the subarray of the AESA; and
perform T/R calibration with respect to the radiative loopback values.
15 . The radar system of claim 13 ,
wherein the at least one processor is further configured to balance a relative amplitude and phase for at least one transmit channel.
16 . The radar system of claim 13 , wherein the AESA comprises at least a one dimensionally conformal array.
17 . The radar system of claim 13 , further comprising one or more additional AESAs, wherein the at least one processor is further configured to perform relative amplitude and phase calibration for the one or more additional AESAs.