In this video I go over the J2 (earth oblateness) orbital perturbation. This is the first video on a sub series of orbital perturbation videos, where I will discuss orbital perturbations and then how to implement them in the differential equation passed into OrbitPropagator. I go over why earth is an oblate spheroid and not a perfect sphere and why that affects orbits. I then do an example with the ISS orbit.

THERE ARE 2 MISTAKES IN THIS VIDEO.
1. I mixed up radians and degrees here, so the plot that I output is an equitorial orbit instead of ISS's real orbit which is inclined around 51 degrees. In video 10, you can see that the inclination is oscillating around 0.9 where its supposed to be around 51, because 0.9 radians = 51.5 degrees. My apologies for this mistake.
2. In planetary_data.py, the J2 value of Earth is negative. **THIS IS WRONG**. The value of J2 is defined as a positive number, please remove that negative sign when plugging in this number into your own scripts. Thank you to a follower who found this error and commented it on video 11.

Pre-req videos:
1. Introduction / Overview - [ Ссылка ]
2. Two Body Problem / ODE Solvers - [ Ссылка ]
6. Keplerian Orbital Elements - [ Ссылка ]

Optional videos:
3. Developing the 3D Plotting Function - [ Ссылка ]
4. Developing the OrbitPropagator Class and the Planetary Data File - [ Ссылка ]
5. tools.py and the plot_n_orbits() function - [ Ссылка ]
7. Two Line Element Sets (TLEs) - [ Ссылка ]

Videos for explanation of Earth oblateness:
[ Ссылка ]
[ Ссылка ]

свернуть