Effect of Ephemeris on Pulsar Timing and Navigation Accuracy Based on X-ray Pulsar Navigation-I Data

Abstract

Solar system ephemeris is very important for pulsar timing and navigation. In order to explore the effect of different precision ephemerides on X-Ray pulsar timing and navigation, the differences between timing and navigation results with four JPL Development Ephemerides based on the data of x-ray pulsar navigation-I (XPNAV-I) were compared and analyzed in this paper. For pulsar timing, the ephemeris has a systematic effect on time scale conversion (nanosecond difference), light-travel delay (millisecond difference) and timing residuals (microsecond difference), and the pulse profile phase can reflect the systematic deviation caused by different ephemerides in the timing calculation. The timing results show that it is necessary to compile the pulsar timing model based on the newer ephemeris. For navigation, based on the significant enhancement of pulse profile with orbit-dynamic (SEPO), the absolute error between simulation orbit and actual orbit is less than 2 km for each ephemeris, and the differences between simulation orbits are less than 1 km. The orbit position accuracy calculated by the ephemeris used in pulsar timing parameter calculation is the highest (DE200 in this paper), which explains the necessity of using a unified ephemeris in the calculation of timing and navigation with satisfying its internal self-consistency.

The Influence of Different Solar System Planetary Ephemerides on Pulsar Timing

“…Therefore, the differences and errors inherent in an ephemeris have a certain impact on pulsar timing, especially for high-precision timing (Lazio et al 2018). The difference in Roemer delay caused by different ephemerides (DE200, DE405, DE421, and DE430) was greater than 1 ms (Deng & Jin 2022). Conversely, the PTA data were used to constrain the upper mass limits of unidentified asteroids in the solar system (Caballero 2018), and well as the masses of the major planets in the solar system were estimated by analyzing pulsar timing data (Champion et al 2011), in addition to the influence of ephemeris error on pulsar timing being studied by disturbing different parameters of the LINIMOS ephemeris (Guo et al 2019).…”