Multi-Frequency Based Direction-of-Arrival Estimation for 2q-Level Nested Radar & Sonar Arrays

Area of Science:

• Radar and Sonar Systems
• Signal Processing
• Array Signal Processing

Background:

• Direction finding is crucial in radar and sonar.
• High-resolution direction of arrival (DOA) estimation can be achieved using higher-order cumulants with nested arrays.
• Existing methods face challenges with virtual array 'holes' and frequency requirements.

Purpose of the Study:

• To address limitations in existing DOA estimation algorithms for nested arrays.
• To propose a novel multi-frequency method that overcomes the challenges of virtual element gaps.
• To improve the performance and efficiency of DOA estimation.

Main Methods:

• Utilizing 2qth-order cumulants for DOA estimation with 2q-level nested arrays.
• Generating a virtual 2qth-order difference co-array with O(N^2) virtual sensors.
• Introducing a multi-frequency method for a minimum number of frequencies (MFMNF) to fill virtual array holes.

Main Results:

• The MFMNF method effectively fills all virtual array holes using a single frequency.
• This results in a longer virtual array compared to the multi-frequency method for minimum frequency separation (MFMFS).
• Simulation results demonstrate improved DOA estimation performance with the MFMNF method.

Conclusions:

• The proposed MFMNF method offers a more efficient and effective approach to DOA estimation in radar and sonar systems.
• It overcomes the limitations of previous methods regarding virtual array gaps and frequency constraints.
• The method enhances DOA estimation performance by creating a longer, denser virtual array.