Abstract:  With the requirements of massive data transmission between satellite platform and ground sensors，the frequency band of data transmission has been extended from the traditional X band to Ka band.The Ka band satellite target with narrow beam and high dynamic puts forward higher requirements for the acquisition and tracking performance of ground receiving system.For different working models of the Ka band antenna，the influencing factors such as antenna tracking accuracy，electric axis consistency and search range in the capture process were analyzed.Then a capture probability model，which can be approximated to the modified Rayleigh distribution，was proposed.The sensitivity of different influencing factors to target acquisition was simulated and analyzed，and the properties of Ka band capture probability were summarized.Finally，the actual tracking of a certain device was verified and analyzed，which provides an analysis basis for effectively improving the capturing and tracking ability of Ka band antenna.

Key words: target acquisition, tracking accuracy, Ka band, probability distribution, dual band antenna