Beamforming Techniques for Passive Radar: An Overview

Abstract

Passive radar is an interesting approach in the context of non-cooperative target detection. Because the signal source takes advantage of the so-called illuminator of opportunity (IoO), the deployed system is silent, allowing the operator cheap, portable, and practically undetectable deployments. These systems match perfectly with the use of antenna arrays to take advantage of the additional gains provided by the coherent combination of the signals received at each element. To obtain these benefits, linear processing methods are required to enhance the system’s performance. In this work, we summarize the main beamforming methods in the literature to provide a clear picture of the current state of the art. Next, we perform an analysis of the benefits and drawbacks and explore the chance of increasing the number of antenna elements. Finally, we identify the major challenges to be addressed by researchers in the future.

Rotating Target Detection Using Commercial 5G Signal

“…In Figure 2, the symbol location is five, startin from the fifth OFDM symbol, and the subcarrier location is one, starting from the firs subcarrier. [15]. Where v is the velocity of the target, L is the distance between the receiving and transmitting antennas, L T is the distance between the target and the transmitting antenna, L R is the distance between the target and the receiving antenna, β is the double base angle, and δ is the angle of the target at the velocity direction relative to the bisector of the double base angle.…”

“…Utilizing 5G signals for rotating target detection essentially employs bistatic radar principles for target identification. The transmitting antenna and receiving antenna of the bistatic radar are separated from each other, and their structural model is shown in Figure 3 [15]. Where v is the velocity of the target, L is the distance between the receiving and transmitting antennas, T L is the distance between the target and the transmitting antenna, R L is the distance between the target and the receiving antenna, β is the double base angle, and δ is the angle of the target at the velocity direction relative to the bisector of the double base angle.…”