Planetary Radar Feed Array Calibration Using Sub-Reflector Horns
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Solution Overview
Problem
Calibration of high-power radio telescopes is challenging due to the size of the assembly and high output power, making safe terrestrial calibration reflectors impractical, necessitating a unique calibration scheme for proper phase array based transmitter feed operation.
Innovation Solution
A calibration system using RX and TX calibration processes, involving a RX calibration horn adjacent to the transmitter feed array and a second RX calibration horn in the sub-reflector, to establish orientations and synchronize TX elements through simultaneous offset transmissions, ensuring coherent signal transmission.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a terrestrial calibration reflector is used for high-power radio telescope calibration, then calibration can be performed, but the large size and high output power make safe terrestrial calibration reflectors impractical
Solution Approach 1:
The patent introduces an intermediary calibration system consisting of calibration horns and low-power signal sources that mediate between the high-power transmitter and the calibration process. The calibration horns are positioned in the focal regions where signal concentration occurs, allowing calibration measurements to be made with low-power signals rather than requiring high-power terrestrial reflectors.
Solution Approach 2:
The patent creates a virtual copy of the far-field calibration condition by using calibration horns positioned at the focal points. Instead of physically transporting or deploying large terrestrial calibration reflectors, the system copies the essential calibration function through strategically positioned receivers that measure the beam patterns and phase distributions directly at the focal regions.
2Measurement precision
If traditional calibration methods are used, then calibration can be performed, but the process is time-consuming and complex for large phased array systems
Solution Approach 1:
The patent divides the calibration process into distinct segments: RX calibration using the calibration horn in the reflector's focal region to establish baseline measurements, and TX calibration using the calibration horn in the sub-reflector's focal region to measure transmitted beam patterns. This segmentation allows systematic calibration of different array elements and sub-arrays, making the complex calibration process more manageable and efficient.
Solution Approach 2:
The patent performs preliminary RX calibration before TX calibration operations. By first establishing the receiver calibration using low-power signals and then using those calibrated receivers to guide the transmitter calibration, the system prepares the measurement infrastructure in advance, reducing the overall calibration time and improving accuracy.
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
Enables efficient and cost-effective real-time calibration of high-power planetary radar systems, aligning reflector and sub-reflector orientations, and synchronizing TX elements, ensuring accurate and coherent radio signal transmission.
Implementation Method 1
a sub-reflector configured to receive the radio signal from the transmitter feed array and reflect the radio signal to the large reflector
Data Source
AI summary
A transmitter system includes a transmitter feed array configured to generate a radio signal. The transmitter system also includes a reflector configured to transmit the radio signal outward in a narrow beam. The transmitter system further includes a sub-reflector configured to receive the radio signal from the transmitter feed array and reflect the radio signal to the reflector before the radio signal is transmitted. The transmitter system also includes a calibration system comprising a first receiver (RX) calibration horn adjacent to the transmitter feed array and a second RX calibration horn disposed in a center of the sub-reflector, the calibration system configured to be used in a RX calibration process and a transmitter (TX) calibration process of the transmitter system.