First, the inclination angle is zero, the orbital plane of the satellite coincides with the equatorial plane of the earth, and the satellite always flies over the equator. This orbit is called equatorial orbit.

Second, the inclination angle is 90 degrees, the plane where the satellite orbits is perpendicular to the equatorial plane of the earth, and the satellite flies over the north and south poles, which is called polar orbit.

Third, the inclination of the track is neither zero nor 90 degrees, which is collectively called inclined track. Among them, if the inclination angle is greater than zero and less than 90 degrees, the satellite runs from west to east along the earth's rotation direction, which is called forward orbit; If the inclination angle is more than 90 degrees and less than 180 degrees, the satellite runs against the direction of the earth's rotation from east to west, which is called retrograde orbit.