Radar Module Calibration Using Delay Line
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Solution Overview
Problem
Current ultra-high frequency early-warning radar systems rely on manual and time-consuming calibration methods, which are limited in accuracy and cannot correct for all errors in the RF path, affecting the sensitivity and tracking performance of the radar, and are not suitable for real-time calibration required by future upgrades.
Innovation Solution
An automated calibration method using time domain reflectometry to measure and adjust the electrical lengths of sub-array transmit and receive paths, allowing for digital control and correction of phase shifts in solid state modules, enabling precise calibration of radar systems without external hardware.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If manual calibration methods are used with external RFM equipment, then sub-array alignment can be achieved, but the process is time-consuming and cannot calibrate the radar front end
Solution Approach 1:
The patent extracts the calibration functionality from external equipment into the radar system itself by implementing an internal reflectometer that uses existing radar components (transmit/receive switches, delay lines, phase shifters) to perform self-calibration, eliminating the need for external RFM equipment and manual procedures
Solution Approach 2:
The radar system performs self-calibration using its own internal resources - the reflectometer is implemented within the radar using existing hardware components, allowing the system to calibrate itself automatically without external intervention or manual adjustment
2Reliability
If factory alignment of modules is performed, then element calibration can be achieved, but it cannot correct for all errors in the RF path and limits radar performance
Solution Approach 1:
The patent makes existing radar components multi-functional - the transmit/receive switches, delay lines, and phase shifters are used both for normal radar operation and for calibration measurements, eliminating the need for separate dedicated calibration hardware and reducing overall system complexity
Solution Approach 2:
The patent introduces an internal reflectometer as an intermediary measurement system that uses the existing radar hardware to indirectly measure and characterize RF path errors, enabling comprehensive calibration without adding complex direct measurement equipment
3Ease of operation
If manual adjustments to sub-array line lengths are made, then sub-array alignment can be achieved, but beam steering accuracy is limited and sensitivity deteriorates
Solution Approach 1:
The patent replaces static manual adjustments with dynamic electronic control - phase shifters and delay lines are controlled electronically to provide continuous, precise adjustment of signal paths, enabling accurate beam steering and compensation for RF path errors without physical reconfiguration
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The automated calibration method improves beam steering accuracy by 70% and sensitivity by 0.5 dB, reducing errors and enabling real-time calibration necessary for future radar technology upgrades.
Implementation Method 1
measuring a first electrical length which is a round-trip electrical length of a sub-array transmit path from a first radar signal input port to a first terminal of a circulator in a sub-array driver module of a sub array of the radar apparatus using time domain reflectometry
Implementation Method 2
The transmit signal is separated from the receive signal with the circulator 121
Implementation Method 3
Each antenna element is delayed by the correct amount so that a wave front arriving from a given direction is aligned to receive the signals
Implementation Method 4
Beams can be formed by shifting the phase of signals emitted from each radiating element to provide constructive and destructive interference
Data Source
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AI summary
An apparatus and method for enhanced calibration of radar at the module level supports dual polarization and array calibration and alignment without the use of external test equipment. Utilizing a delay line, loop back capability at the module level allows existing receiver exciter subsystem to be used for calibration. This approach eliminates the need for manual array calibration using external RF monitor subsystem or external test antennas.