  The method of restricted path integrals allows one to effectively consider
continuous (prolonged in time) measurements of quantum systems. Monitoring of
the system coordinates is such a continuous measurement that allows one to
describe a quantum system in terms of trajectories. This approach is applied to
chaotic systems. The behavior of such systems is qualitatively investigated in
classical and quantum regimes of the coordinate monitoring. The comparison of
classical and quantum chaos in terms of trajectories is performed.
Characteristic features of chaotic systems (observables) with respect to
continuous measurements are analyzed in comparison with those of regular
(non-chaotic) and quantum-nondemolition variables.
