This paper evaluates the positioning accuracy, integrity, and availability regarding the impact of ionospheric disturbances in low-latitude regions on the navigation performance of GBAS(Ground-Based Augmentation System). By establishing a dynamic test platform in an ionospherically active area(An airport in the Southeast Asian region which is located in a low-latitude area) and integrating measured data of ionospheric gradients and scintillation index S4, the navigation performance of the GBAS system under abnormal ionospheric conditions is verified. The experiment simulates the aircraft approach process and analyzes the influence of ionospheric disturbances on positioning accuracy, integrity, and availability under two modes: GPS and BDS GAST_C(GPS single-frequency 、 BDS single-frequency in GBAS). The results show that GBAS has reliable abnormal satellite correction capability in the low-latitude ionospheric disturbance environment, and its positioning accuracy, integrity, and availability all meet the requirements for Category I precision approach set by the International Civil Aviation Organization(ICAO)and the Civil Aviation Administration of China(CAAC).