Dynamic lock-in

Dynamic lock-in is a method used in laser trackers to improve the accuracy of distance measurement and enhance system stability when tracking moving objects.

In general, a laser tracker works by sending a laser beam to a reflector mounted on the object being measured, and then receiving the reflected light back at the tracker, where the distance to the reflector is calculated. The dynamic lock-in system generates an alternating current signal that is modulated with the frequency of the laser beam sent by the tracker. The signal is then fed to the photodetector in the tracker that receives the reflected light.

The signal is compared to a reference signal generated by a reference source that is synchronized with the dynamic lock-in system. The difference between the modulated signal and the reference signal is called the "error" and serves as input to the controller of the dynamic lock-in system.

The system then adjusts the amplitude and phase of the modulated signal to minimize the error. This results in higher accuracy in distance measurement as the signal is amplified while noise and disturbances are filtered out.

Another advantage of the dynamic lock-in system is that it improves system stability when tracking moving objects. Since the system adjusts the amplitude and phase of the signal, it can quickly respond to changes in the position of the reflector, thus providing accurate measurement even when the object is in motion.

Overall, the dynamic lock-in system provides an effective method to improve the accuracy and stability of laser trackers, especially when measuring moving objects.