The influence of tesseral harmonic J_{22} term on the TLE orbit error of low polar orbit satellite
Abstract
By expanding the perturbation function of tesseral harmonic J_{22} term of the earth's non spherical gravitation, it is found that there is a term cos2 Ω_{e} related to the rotation of the earth. The period of the term is half a day, and the coefficient includes the factor sin^{2}i related to the orbital inclination angle. For the low polar orbit satellite with orbit inclination close to 90^{∘}, J_{22} term has a great impact on the orbit accuracy, which will reach the order of kilometers. Based on the measured orbit data (historical TLEs and GPS precise ephemeris) of the polar satellite GRACEA/B, the influence of the tesseral harmonic J_{22} term on TLE orbit error is further verified. It is found that the system bias caused by ignoring J_{22} term exists in TLE orbit data for LEO, which shows a periodic change of 180 degrees with the geographic longitude in the intrack direction. In addition, the accuracy of TLE orbit in the northern hemisphere is significantly higher than that in the southern hemisphere, which is related to the distribution of SSN observation network. For GRACEA satellite, the maximum system bias of TLE orbit can reach close to 1.5 km near the equator of the earth, and 8 km after a 7day prediction period.
 Publication:

Astrophysics and Space Science
 Pub Date:
 January 2021
 DOI:
 10.1007/s10509020039160
 Bibcode:
 2021Ap&SS.366....5X
 Keywords:

 Tesseral harmonic;
 TLE;
 Orbit error;
 System bias;
 Collision risk assessment