(1) CHAMP tracking station, gravity field, atmosphere, GPS occultation.

(2) Radio occultation technique can provide the Earth's ionospheric and neutral atmosphere with high accuracy, high vertical resolution and global coverage.

(3) The probe was equipped with a radio occultation experiment to profile atmospheric density.

(4) Although TAOS was designed to detect occultation events, the enormous amount of data and the short exposure time provide an archive for searching variable stars with rapid variabilities.

(5) The noise occultation was significant, and the undertone was the easiest one to be occulted.

(6) If LEO satellite orbit changes , then the occultation events number and distribution will be different.

(7) After a long period of occultation he again showed his face at the club.

(8) The probe was equipped with a occultation experiment to profile atmospheric density.

(9) The global variation characteristics of tropopause are shown by analyzing the data of temperature profiles from Radio Occultation(RO) observations aboard the satellites of COSMIC.

(10) These prove that the calibrated TEC method is a good algorithm for inversion of ionospheric GPS occultation, especially when the LEO's orbit is low.

(11) The principle and methods estimating bending angles of the radio rays and atmospheric refractivity profiles with the mountain-based radio occultation data are given.