Reprint of: Taking laser Doppler vibrometry off the tripod: correction of measurements affected by instrument vibration

- 100% sensitivity to instrument motion in beam direction confirmed experimentally.
- Vector-based approach used to define required measurements for complete correction.
- Frequency domain processing including vital finite time delay adjustment described.
- Effectiveness demonstrated experimentally with over 30 dB error reduction confirmed.
- “Real world” measurement described with up to 19 dB error reduction demonstrated.

Laser Doppler vibrometers (LDVs) are now well-established as an effective non-contact alternative to traditional contacting transducers. Despite 30 years of successful applications, however, very little attention has been given to sensitivity to vibration of the instrument itself. In this paper, the sensitivity to instrument vibration is confirmed before development theoretically and experimentally of a practical scheme to enable correction of measurements for arbitrary instrument vibration. The scheme requires a pair of correction sensors with appropriate orientation and relative location, while using frequency domain processing to accommodate inter-channel time delay and signal integrations. Error reductions in excess of 30 dB are delivered in laboratory tests with simultaneous instrument and target vibration over a broad frequency range. Ultimately, application to measurement on a vehicle simulator experiencing high levels of vibration demonstrates the practical nature of the correction technique and its robustness in a challenging measurement environment.