Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Characterization of Pulsar Sources for X-ray Navigation   The Station Explorer for X-ray Timing and Navigation Technology (SEXTANT) is
a technology demonstration enhancement to the Neutron Star Interior Composition
Explorer (NICER) mission, which is scheduled to launch in 2017 and will be
hosted as an externally attached payload on the International Space Station
(ISS). During NICER's 18-month baseline science mission to understand
ultra-dense matter through observations of neutron stars in the soft X-ray
band, SEXTANT will, for the first-time, demonstrate real-time, on-board X-ray
pulsar navigation. Using NICER/SEXTANT as an example, we describe the factors
that determine the measurement errors on pulse times of arrival, including
source and background count rates, and pulse profile shapes. We then describe
properties of the SEXTANT navigation pulsar catalog and prospects for growing
it once NICER launches. Finally, we describe the factors affecting the
prediction of pulse arrival times in advance, including variable interstellar
propagation effect and red timing noise. Together, all of these factors
determine how well a particular realization of an X-ray pulsar-based navigation
system will perform.

4
The categories of this paper are: cond-mat
26
The categories of this paper are: bayes-an
29
The categories of this paper are: funct-an
35
The categories of this paper are: mtrl-th
30
The categories of this paper are: q-alg
36
The categories of this paper are: cmp-lg
31
The categories of this paper are: ao-sci
33
The categories of this paper are: plasm-ph
0
The categories of this paper are: hep-ph
12
The categories of this paper are: nucl-th
28
The categories of this paper are: alg-geom
23
The categories of this paper are: solv-int
1
The categories of this paper are: cs
9
The categories of this paper are: nlin
17
The categories of this paper are: q-fin
7
The categories of this paper are: hep-th