Detection of Martian ionosphere

The exploration of Mars began in the early 1960s and has become the main subject of the space exploration recently. The Chinese deep space project (mainly focused on Mars) is developing. ``Land on Mars and live on Mars'' is the ultimate object for the Mars exploration and the Martian ionosphere is one of the environments to be understood necessarily. In this paper the basic methods of the Martian ionospheric detection and the typical results are introduced. The direct detection has the advantages of high precision, good spatial resolution, but it can not provide a long-term stable observation due to the short measuring time. The main indirect detection results of the Martian ionosphere come from the radio occultation method and the topside sounder. The radio occultation measurement provides a long-term stable detection of the whole profile of Martian ionosphere, but its horizontal resolution is not good and the Solar Zenith Angle (SZA) range of the measurement is limited by the orbits of Earth and Mars. The topside sounder can also provide a long-term stable measurement with high temporal and spatial resolutions, which gives new support for Martian ionospheric exploration. The combination of these detection methods will greatly improve the research of Martian ionosphere.