  This paper proposes an integrated sensing, navigation, and communication
(ISNC) framework for safeguarding unmanned aerial vehicle (UAV)-enabled
wireless networks against a mobile eavesdropping UAV (E-UAV). To cope with the
mobility of the E-UAV, the proposed framework advocates the dual use of
artificial noise transmitted by the information UAV (I-UAV) for simultaneous
jamming and sensing to facilitate navigation and secure communication. In
particular, the I-UAV communicates with legitimate downlink ground users, while
avoiding potential information leakage by emitting jamming signals, and
estimates the state of the E-UAV with an extended Kalman filter based on the
backscattered jamming signals. Exploiting the estimated state of the E-UAV in
the previous time slot, the I-UAV determines its flight planning strategy,
predicts the wiretap channel, and designs its communication resource allocation
policy for the next time slot. To circumvent the severe coupling between these
three tasks, a divide-and-conquer approach is adopted. The online navigation
design has the objective to minimize the distance between the I-UAV and a
pre-defined destination point considering kinematic and geometric constraints.
Subsequently, given the predicted wiretap channel, the robust resource
allocation design is formulated as an optimization problem to achieve the
optimal trade-off between sensing and communication in the next time slot,
while taking into account the wiretap channel prediction error and the
quality-of-service (QoS) requirements of secure communication. Simulation
results demonstrate the superior performance of the proposed design compared
with baseline schemes and validate the benefits of integrating sensing and
navigation into secure UAV communication systems.
