A Technique for Removing Platform Vibration Noise From A Pulsed Ladar Vibration Sensor

Document Type

Article

Publication Date

10-1995

Publication Source

Optics & Laser Technology

Abstract

A technique has been developed for removing platform-induced vibration noise from a pulsed ladar vibration sensor. Deriving the vibrational characteristics of the platform is accomplished by simulating ambient atmospheric aerosols as a stationary reference target. Using a pulsed coherent detection ladar, the instantaneous Doppler frequency shifts from both aerosols and a distant hard target are measured and recorded, while the data acquisition is range gated so that both Doppler measurements are made from a single pulse. Periodic measurements are then made to develop a time history of the fluctuations in the Doppler signals, after which two vibration spectra are derived by Fourier transforming the time histories of the instantaneous Doppler shifts. The first spectrum contains information regarding the relative motion between the target and platform, while the second spectrum contains information regarding the relative motion between the platform and the stationary aerosols. When the second spectrum is subtracted from the first, the resulting spectrum is the true vibrational signature of the target. The advantages of this new technique over conventional continuous wave ladar vibration sensors are: target range information is obtainable; the average power required from the laser is significantly reduced; and additional sensing equipment is not needed to derive the platform-induced noise spectrum. The principles of this technique are experimentally verified using a 2 μm pulsed ladar.

Inclusive pages

343–350

ISBN/ISSN

0030-3992

Publisher

Elsevier

Volume

27

Issue

5

Peer Reviewed

yes

Keywords

vibration sensors, ladar, laser radar, Doppler radar

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