Calibration of correlation radiometers using pseudo-random noise signals

Area of Science:

• Radiometry
• Microwave Engineering
• Signal Processing

Background:

• Accurate calibration of correlation radiometers, especially aperture synthesis interferometric radiometers, is crucial for performance.
• Existing calibration methods using centralized noise injection are complex for large systems.
• Distributed noise injection techniques fail to correct baseline errors.

Purpose of the Study:

• To propose and analyze the use of centralized Pseudo-Random Noise (PRN) signals for calibrating correlation radiometers.
• To investigate novel calibration schemes and signal distribution methods using PRNs.
• To evaluate the performance of PRN-based calibration for microwave correlation radiometers, particularly large aperture synthesis systems.

Main Methods:

• Utilizing Pseudo-Random Noise (PRN) sequences with flat spectral characteristics similar to thermal noise.
• Implementing a centralized PRN signal injection for correlation radiometer calibration.
• Exploring correlation of receiver outputs with local PRN replicas for enhanced calibration.
• Analyzing the performance of PRN calibration in a large aperture synthesis radiometer context, potentially using optical distribution.

Main Results:

• PRN signals offer a deterministic and spectrally suitable alternative to traditional noise sources for radiometer calibration.
• Centralized PRN injection simplifies calibration logistics compared to complex noise distribution networks.
• New calibration schemes leveraging the deterministic nature of PRNs can address baseline errors and improve accuracy.
• The study analyzes the feasibility and performance requirements for PRN calibration in microwave radiometers.

Conclusions:

• Centralized Pseudo-Random Noise (PRN) signal calibration presents a viable and advantageous solution for correlation radiometers.
• PRN-based calibration simplifies complex systems and potentially corrects for baseline errors.
• This approach is particularly promising for large-scale instruments like aperture synthesis radiometers.