Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: High-precision Absolute Distance Measurements over a Long Range Based on
  Two Optoelectronic Oscillators   Absolute distance measurement (ADM) over a long range has been studied
intensely over the last several decades, due to its important applications in
large-scale manufacturing and outer space explorations [1-5]. Traditional
absolute distance measurements utilize detection of time-of-flight information,
detection of phase shift, or a combination of the two [6-17]. In this paper, we
present a novel scheme for high-precision ADM over a long range based on
frequency detection by using two optoelectronic oscillators (OEO) to convert
distance information to frequency information. By taking advantage of
accumulative magnification theory, the absolute error of the measured distance
is magnified by about 2*10E5 times, which makes the precision of the measured
distance significantly improved. In our experiments, the maximum error is 1.5
um at the emulated ~6 km distance, including the drift error of about 1 um in
the air path due to the change in environmental conditions. In addition, the
measurable distance using this scheme could be further extended. The highest
relative measurement precision is 2*10E10 in our current system while the
actual relative measurement precision of our experimental system is limited by
the variation of atmospheric conditions and is about 4*10E9.

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The categories of this paper are: cond-mat
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The categories of this paper are: alg-geom
23
The categories of this paper are: solv-int
32
The categories of this paper are: atom-ph
13
The categories of this paper are: quant-ph
9
The categories of this paper are: nlin
27
The categories of this paper are: comp-gas
22
The categories of this paper are: chao-dyn
29
The categories of this paper are: funct-an
19
The categories of this paper are: eess
35
The categories of this paper are: mtrl-th
12
The categories of this paper are: nucl-th
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The categories of this paper are: math
33
The categories of this paper are: plasm-ph
5
The categories of this paper are: gr-qc
31
The categories of this paper are: ao-sci