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1. chinaXiv:201605.00220 [pdf]

A continuous cold atomic beam interferometer

Xue, Hongbo; Feng, Yanying; Chen, Shu; Wang, Xiaojia; Yan, Xueshu; Jiang, Zhikun; Zhou, Zhaoying
Subjects: Geosciences >> Space Physics

We demonstrate an atom interferometer that uses a laser-cooled continuous beam of Rb-87 atoms having velocities of 10-20 m/s. With spatially separated Raman beams to coherently manipulate the atomic wave packets, Mach-Zehnder interference fringes are observed at an interference distance of 2L - 19 mm. The apparatus operates within a small enclosed area of 0.07 mm(2) at a bandwidth of 190 Hz with a deduced sensitivity of 7.8 x 10(-5) rad/s/root Hz for rotations. Using a low-velocity continuous atomic source in an atom interferometer enables high sampling rates and bandwidths without sacrificing sensitivity and compactness, which are important for applications in real dynamic environments. (C) 2015 AIP Publishing LLC.

submitted time 2016-05-04 Hits282Downloads160 Comment 0

2. chinaXiv:201605.00314 [pdf]

Wide-band chaotic noise signal for velocity estimation and imaging of high-speed moving targets

Yang, Qilun; Zhang, Yunhua; Gu, Xiang
Subjects: Geosciences >> Space Physics

This paper proposes a burst model of chaotic noise signals with randomly stepped carrier frequencies for velocity estimation and high-resolution range imaging of high-speed moving targets. The random stepping of carrier frequencies is controlled by a combination chaotic map (CCM), which is generated by embedding a Logistic map into a Bernoulli map. The baseband noise signal adopts the CCM based frequency-modulation (CCM-FM) signal, which has good randomness and a thumbtack ambiguity function as well. The velocity estimation includes a coarse search and a precise search, where the coarse search is conducted with a fixed step to makes the velocity deviation less than the velocity resolution, while the precise search adopts the Golden Section Search (GSS) algorithm to get an accurate estimation of velocity. What should be emphasized is that the velocity estimation process can be completed with just a burst of subpulses. Then the spectra are coherently synthesized to obtain ultra-wide bandwidth and high-resolution range imaging. Finally, numerical simulations demonstrate a good performance of the proposed signal model and the processing algorithm.

submitted time 2016-05-03 Hits547Downloads325 Comment 0

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