  We here investigate secure control of networked control systems developing a
new dynamic watermarking (DW) scheme. Firstly, the weaknesses of the
conventional DW scheme are revealed, and the tradeoff between the effectiveness
of false data injection attack (FDIA) detection and system performance loss is
analysed. Secondly, we propose a new DW scheme, and its attack detection
capability is interrogated using the additive distortion power of a closed-loop
system. Furthermore, the FDIA detection effectiveness of the closed-loop system
is analysed using auto/cross covariance of the signals, where the positive
correlation between the FDIA detection effectiveness and the watermarking
intensity is measured. Thirdly, the tolerance capacity of FDIA against the
closed-loop system is investigated, and theoretical analysis shows that the
system performance can be recovered from FDIA using our new DW scheme. Finally,
experimental results from a networked inverted pendulum system demonstrate the
validity of our proposed scheme.
