The orbits of satellites are all elliptical, but in high school, for the convenience of studying problems, they are generally treated as circles. But near-earth satellites are closer to circular satellites, which are divided into equatorial satellites, polar satellites and other satellites, because the orbital plane of synchronous satellites is also equatorial. Equatorial near-earth satellites and synchronous earth satellites can be regarded as circles, while polar satellites should be ellipses because of their different accelerations. But most satellites are elliptical, and there is no perfect round satellite. But if you are solving physics problems, we will regard them as circular orbits in high school for convenience. If you are solving a math problem, it may be an ellipse.