Time and Doppler Correlation for Passive Acoustic Ranging

Automated Passive Acoustic Tracking of Dolphins in Free-ranging Pods

Research in passive acoustic detection and localization of marine mammals has largely focused on isolated cases of single or few individuals. However, many marine mammals, such as dolphins, characteristically aggregate in large pods. In addition, dolphins vocalize frequently, emitting broadband clicks and frequency-modulated whistles, which, coupled with a large number of individuals, further c...

Acoustic resolution photoacoustic Doppler velocity measurements in fluids using time-domain cross-correlation

Blood flow measurements have been demonstrated using the acoustic resolution mode of photoacoustic sensing. This is unlike previous flowmetry methods using the optical resolution mode, which limits the maximum penetration depth to approximately 1mm. Here we describe a pulsed time correlation photoacoustic Doppler technique that is inherently flexible, lending itself to both resolution modes. Do...

Passive ranging using image expansion

This paper describes a new technique for passive ranging which is of special interest in areas such as covert nap-of-the-earth helicopter flight and spacecraft landing. This technique is based on the expansion experienced by the image-plane projection of an object as its distance from the sensor decreases. The motion and shape of a small window, assumed to fall inside the boundaries of some obj...

Scalability of Passive and Active Solutions for Time-Based Ranging in IEEE 802.11 Networks

Synergism of Binocular and Motion Stereo for Passive Ranging

0018-9251/9464.00 @ 1994 IEEE Range measurements to objects in the world relative to mobile platforms such as ground or air vehicles are critical for visually aided navigation and obstacle detectiodavoidance. Active (laser) range sensors can be used to provide such range measurements although they have a limited field of view (FOV), suffer from slow data acquisition, and are expensive. Robust p...