Orbit Determination Using Pulsar Timing Data and Orientation Vector

2018 ◽  
Vol 72 (1) ◽  
pp. 155-175
Author(s):  
Hua Zhang ◽  
Rong Jiao ◽  
Luping Xu
Keyword(s):  
Position Estimation ◽  
Position Vector ◽  
Searching Strategy ◽  
Pulsar Timing ◽  
Pulsar Radiation ◽  
Timing Data ◽  
Orientation Vector ◽  
Observation Function ◽  
Difference Filter ◽  
Searching Method

X-ray Pulsar Navigation (XPNAV) uses the Time Difference of Arrival (TDOA) of the pulsar signal between the spacecraft and Solar System Barycentre (SSB) to determine position. In this paper, a novel method to improve the performance of XPNAV via exploiting the pulsar position vector is proposed. First, the field of view of the collimator is utilised to find the pulsar orientation direction. Then, a searching strategy based on the modified Powell method under given coordinate frames is proposed. We also mathematically prove the existence of the extreme value of the searching strategy. Subsequently, an observation model based on the pulsar radiation vector is presented and applied to formulate the observation function together with pulsar time transfer function. Finally, an Adaptive Divided Difference Filter (ADDF) algorithm is introduced to iteratively estimate the position and velocity of the spacecraft. Numerical simulations show that the vector searching method is feasible and the pulsar radiation direction can improve the navigation performance by 75%. The simulation results also show that the ADDF performs better than Unscented Kalman Filtering (UKF) and DDF in position estimation.

scholarly journals Ensemble Pulsar Time Study by Pulsar Timing Observations

2004 ◽  
Vol 218 ◽  
pp. 439-440
Author(s):  
Tinggao Yang ◽  
Guangren Ni
Keyword(s):  
Time Scale ◽  
Wavelet Decomposition ◽  
Time Study ◽  
Millisecond Pulsar ◽  
Millisecond Pulsars ◽  
Pulsar Time ◽  
Pulsar Timing ◽  
Timing Data ◽  
Gravitational Wave Background

Long term timing of multiple millisecond pulsars can contribute to the study of an ensemble pulsar time scale PTens. A wavelet decomposition algorithm (WDA) was applied to define a PTens using the available millisecond pulsar timing datA. The PTens obtained from WDA is more stable than those resulting from other algorithms. The Chinese 50 m radio telescope is specially designed for PTens study and detection of gravitational wave background via millisecond pulsars timing observations. A scheme for multiple millisecond pulsar timing and ensemble pulsar time study is discussed in some detail.

scholarly journals Hyper-efficient model-independent Bayesian method for the analysis of pulsar timing data

2013 ◽  
Vol 87 (10) ◽  
Author(s):  
Lindley Lentati ◽  
P. Alexander ◽  
M. P. Hobson ◽  
S. Taylor ◽  
J. Gair ◽  
...  
Keyword(s):  
Bayesian Method ◽  
Pulsar Timing ◽  
Timing Data ◽  
Model Independent

scholarly journals The International Pulsar Timing Array: second data release

2019 ◽  
Vol 490 (4) ◽  
pp. 4666-4687 ◽  
Author(s):  
B B P Perera ◽  
M E DeCesar ◽  
P B Demorest ◽  
M Kerr ◽  
L Lentati ◽  
...  
Keyword(s):  
Gravitational Waves ◽  
High Precision ◽  
Noise Analysis ◽  
Low Frequency ◽  
The North ◽  
Pulsar Timing ◽  
Data Release ◽  
Timing Data ◽  
Noise Models ◽  
Pulsar Timing Array

ABSTRACT In this paper, we describe the International Pulsar Timing Array second data release, which includes recent pulsar timing data obtained by three regional consortia: the European Pulsar Timing Array, the North American Nanohertz Observatory for Gravitational Waves, and the Parkes Pulsar Timing Array. We analyse and where possible combine high-precision timing data for 65 millisecond pulsars which are regularly observed by these groups. A basic noise analysis, including the processes which are both correlated and uncorrelated in time, provides noise models and timing ephemerides for the pulsars. We find that the timing precisions of pulsars are generally improved compared to the previous data release, mainly due to the addition of new data in the combination. The main purpose of this work is to create the most up-to-date IPTA data release. These data are publicly available for searches for low-frequency gravitational waves and other pulsar science.

Novel motion estimation algorithm for image stabilizer

2017 ◽  
Vol 34 (1) ◽  
pp. 77-89
Author(s):  
Shyang-Jye Chang ◽  
Ray-Hong Wang
Keyword(s):  
Motion Vector ◽  
Estimation Algorithm ◽  
Block Matching ◽  
The Novel ◽  
Motion Vectors ◽  
Content Type ◽  
Computation Efficiency ◽  
Searching Strategy ◽  
Vector Estimation ◽  
Searching Method

Purpose The motion vector estimation algorithm is very widely used in many image process applications, such as the image stabilization and object tracking algorithms. The conventional searching algorithm, based on the block matching manipulation, is used to estimate the motion vectors in conventional image processing algorithms. During the block matching manipulation, the violent motion will result in greater amount of computation. However, too large amount of calculation will reduce the effectiveness of the motion vector estimation algorithm. This paper aims to present a novel searching method to estimate the motion vectors effectively. Design/methodology/approach This paper presents a novel searching method to estimate the motion vectors for high-resolution image sequences. The searching strategy of this algorithm includes three steps: the larger area searching, the adaptive directional searching and the small area searching. Findings The achievement of this paper is to develop a motion vector searching strategy to improve the computation efficiency. Compared with the conventional motion vector searching algorithms, the novel motion vector searching algorithm can reduce the motion matching manipulation effectively by 50 per cent. Originality/value This paper presents a novel searching strategy to estimate the motion vectors effectively. From the experimental results, the novel motion vector searching algorithm can reduce the motion matching manipulation effectively, compared with the conventional motion vector searching algorithms.

scholarly journals Pulsar Timing Limits on Very Low Frequency Stochastic Gravitational Radiation

1996 ◽  
Vol 160 ◽  
pp. 132
Author(s):  
Rachel J. Dewey ◽  
Stephen E. Thorsett
Keyword(s):  
Galaxy Formation ◽  
Gravitational Radiation ◽  
Low Frequency ◽  
Radiation Background ◽  
Arrival Times ◽  
Statistical Framework ◽  
Pulsar Timing ◽  
Orbital Decay ◽  
Timing Data ◽  
Gravitational Wave Background

AbstractA low-frequency, stochastic gravitational radiation background can be detected through the irregularities it induces in pulsar arrival times. In this poster we re-examine pulsar timing data presented in Kaspi, Taylor and Ryba (1994) [Ap.J.,428, p. 713] and present an optimal statistical framework for using timing data from a single pulsar to constrain the energy density in a gravitational wave background. Observations of PSRB1855+09 yield an upper limit (95% confidence) 1.0 × 10−8or (90% confidence) 4.8 × 10−9of the closure density at frequency 4.4 × 10−9Hz. This result probably rules out cosmological models that use cosmic strings as seeds for galaxy formation. Using combined observations of the orbital decay of four binary pulsars we also derive weaker limits at frequencies as low as 10−12Hz.

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