Cross Ambiguity Function Peak Width

I am trying to plot the Cross Ambiguity Function of two OFDM signal (1024 subcarriers) reflected from two targets, which are seperated by 30m.

The problem I am facing that the CAF peak width at the range domaing is wide (zero-doppler cut), which means that the range resolution is to low. So, I am just wonderin how would it be possible to reduce the peak width to get high range resolution?

(Note that CAF peak width at doppler domain is sharp (zero-delay cut).

Answer 1

[Abhimenyu]

Hi Wesam,

I understand that you are trying to plot the “cross ambiguity” function of two signals. To improve the range resolution and reduce the peak width, please follow the below listed methods:

1. Increasing the Bandwidth of the signal: Increasing the bandwidth of the OFDM signal can help improve range resolution. This can be achieved by increasing the subcarrier spacing or increasing the overall signal bandwidth. A wider bandwidth results in a narrower main lobe in the range domain, leading to improved range resolution.
2. Longer Observation Time: By collecting data over a longer time, the resolution in the range domain can be effectively increased.
3. Signal Processing Techniques: The range resolution can also be increased by utilizing signal processing techniques such as “matched filtering”, “pulse compression”, or “waveform diversity” to enhance the range resolution. These techniques can help in narrowing the main lobe of the CAF in the range domain.
4. Multiple Receivers: Implementing multiple receivers or antenna arrays can provide spatial diversity, which can be leveraged to improve the range resolution. By processing the received signals from multiple antennas, the localization and resolution of the targets can be enhanced.
5. Advanced Processing Algorithms: The advanced processing algorithms such as “adaptive beamforming”, “spatial filtering”, or “super-resolution” techniques can be employed to extract finer details and improve the range resolution.
6. Noise Reduction: A cleaner signal with reduced noise can lead to improved range resolution and more accurate detection of targets.

By integrating these strategies into the signal processing and analysis, the range resolution in the “cross ambiguity” function of the reflected “OFDM” signals can be improved, allowing for more precise localization and characterization of the targets.

Please refer to the below mentioned MATLAB documentation links to understand more on “matched filtering”, “pulse compression”, “adaptive beamforming”, “super-resolution” and “noise removal” respectively:

• https://www.mathworks.com/help/phased/ug/matched-filtering.html
• https://www.mathworks.com/help/signal/ug/radar-pulse-compression.html
• https://www.mathworks.com/help/phased/ug/adaptive-beamforming.html
• https://www.mathworks.com/help/phased/ug/super-resolution-doa-estimation.html
• https://www.mathworks.com/help/images/noise-removal.html

I hope this helps to resolve the query.

Thanks,

Abhimenyu