  Quantum Parameter Estimation (QPE) is important from the perspective of both
fundamental quantum research and various practical applications of quantum
technologies such as for developing optimal quantum control strategies.
Standard and traditional methods for QPE involve projective measurements on
thousands of identically prepared quantum systems. However, these methods face
limitations, particularly in terms of the required number of samples and the
associated experimental resources. In this work, we present a novel method for
precise QPE that diverges from conventional techniques, employs continuous
measurements, and enables accurate QPE with a single quantum trajectory. In an
application, we demonstrate the use of the method for the task of parameter
estimation and force sensing of a levitated nanoparticle.
