Integrated Communication, Sensing, and Navigation Beamforming Design for Low-Altitude Scenarios

Abstract

To meet the collaborative requirements of high-precision communication, sensing, and navigation for unmanned aerial vehicles (UAVs) and other aerial mobile terminals operating in urban low-altitude airspace, this paper proposes an integrated communication-sensing-navigation (ICSN) beamforming design tailored to low-altitude scenarios. In the developed ICSN system model, communication performance is evaluated by the total communication rate of users, while sensing performance is quantified by the Cramér–Rao Bound (CRB) of target angle estimation, enabling accurate positioning and continuous perception for aerial users. A two-stage beamforming strategy is adopted: in the first stage, a wide beam is constructed under integrated sidelobe to mainlobe ratio (ISMR) constraints to sense potential target directions; in the second stage, a weighted optimization problem is formulated to jointly enhance communication rate and angle estimation accuracy, subject to user signal-to-interference-plus-noise ratio (SINR) requirements and mainlobe/sidelobe constraints. To efficiently solve the resulting non-convex problem, this paper proposes an algorithmic framework that combines fractional programming (FP) and alternating optimization (AO), fully utilizing the perception results from the previous round to perform feedback updates for the next round of beam design. Simulation results verify the effectiveness of the proposed method in multi-user and multi-target urban low-altitude scenarios, demonstrating the role of the first-stage directional beam design in system robustness and accuracy. Moreover, the proposed framework facilitates spectrum and hardware reuse across functionalities, thereby contributing to the design of sustainable and energy-efficient aerial communication systems aligned with the principles of green communication.