Active array self calibration
First Claim
1. A method for receive self calibration of an active RF antenna array system comprising a plurality of radiating elements arranged in an array aperture, a corresponding plurality of transmit/receive modules each including independently adjustable phase shifting circuitry, a transmit signal source for providing transmit signals and a receiver responsive to the signals received through the radiating elements and T/R modules to provide a receiver signal, the method comprising the following steps:
- (a) placing a radar absorbing hat over the array aperture;
(b) setting the transmit drive to an appropriate level to obtain linear operation of the receive module;
(c) setting a given T/R module under test to a receive state;
(d) setting a reference T/R module to a transmit state;
(e) setting all other T/R modules in the array except the module under test and the reference module to a safe state so as not to transmit or receive through said other modules;
(f) receiving pulses of RF energy at the module under test via its corresponding radiating element which has been transmitted through the reference module via its corresponding radiating element;
(g) changing the state of the phase shifting circuitry of the receive module under test on a pulse-to-pulse or between groups of pulses to add phase modulation to the received pulses of energy to collect measurement data;
(h) analyzing the measurement data to determine the relative phase difference between the transmit module and the receive module under test;
(i) repeating the calibration for other modules in the array to obtain a set of data indicating the relative phase differences between the modules in the array, wherein only one module is transmitting and only one module is receiving during a test of a module under test; and
(j) storing the set of data for use in setting the phase shifters for accurate receive beam forming.
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0 Petitions
Accused Products
Abstract
A process for collecting phase and amplitude calibration data for an active array system without the use of external sensors. The relative phase and amplitudes of adjacent T/R modules are determined when viewed through the entire array system. The calibration process involves collecting and storing these phases and amplitudes for future use. A pulse-to-pulse phase or amplitude modulation mode is employed. An element is commanded into this mode to separate its signal (in frequency) from competing signals and leakages from the surrounding modules. A T/R inversion command allows for a single element to be switched to a transmit state while the remainder of the array is in the receive state. This provides for a reference signal during receive calibration, and for single module testing during transmit calibration.
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Citations
12 Claims
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1. A method for receive self calibration of an active RF antenna array system comprising a plurality of radiating elements arranged in an array aperture, a corresponding plurality of transmit/receive modules each including independently adjustable phase shifting circuitry, a transmit signal source for providing transmit signals and a receiver responsive to the signals received through the radiating elements and T/R modules to provide a receiver signal, the method comprising the following steps:
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(a) placing a radar absorbing hat over the array aperture; (b) setting the transmit drive to an appropriate level to obtain linear operation of the receive module; (c) setting a given T/R module under test to a receive state; (d) setting a reference T/R module to a transmit state; (e) setting all other T/R modules in the array except the module under test and the reference module to a safe state so as not to transmit or receive through said other modules; (f) receiving pulses of RF energy at the module under test via its corresponding radiating element which has been transmitted through the reference module via its corresponding radiating element; (g) changing the state of the phase shifting circuitry of the receive module under test on a pulse-to-pulse or between groups of pulses to add phase modulation to the received pulses of energy to collect measurement data; (h) analyzing the measurement data to determine the relative phase difference between the transmit module and the receive module under test; (i) repeating the calibration for other modules in the array to obtain a set of data indicating the relative phase differences between the modules in the array, wherein only one module is transmitting and only one module is receiving during a test of a module under test; and (j) storing the set of data for use in setting the phase shifters for accurate receive beam forming. - View Dependent Claims (2, 3, 4, 5, 6)
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7. A method for transmit self calibration of an active RF antenna array system comprising a plurality of radiating elements arranged in an array aperture, a corresponding plurality of transmit/receive modules each including independently adjustable phase shifting circuitry, a transmit signal source for providing transmit signals and a receiver responsive to the signals received through the radiating elements and T/R modules to provide a receiver signal, the method comprising the following steps:
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(a) placing a radar absorbing hat over the array aperture; (b) setting the transmit drive to an appropriate level to obtain linear operation of the receive module; (c) setting a given T/R module under test to a transmit state; (d) setting a reference T/R module to a receive state; (e) setting all other T/R modules in the array except the module under test and the reference module to a safe state so as not to transmit or receive through said other modules; (f) receiving pulses of RF energy at the module under test via its corresponding radiating element which has been transmitted through the module under test via its corresponding radiating element; (g) changing the state of the phase shifting circuitry of the module under test on a pulse-to-pulse or between groups of pulses to add phase modulation to the received pulses of energy to collect measurement data; (h) analyzing the measurement data to determine the relative phase difference between the module under test and the reference module; (i) repeating the calibration for other modules in the array to obtain a set of data indicating the relative phase differences between the modules in the array, wherein only one module is transmitting and only one module is receiving during a test of a module under test; and (j) storing the set of data for use in setting the phase shifters for accurate transmit beam forming. - View Dependent Claims (8, 9, 10, 11, 12)
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Specification