Abstract: iGMAS (international GNSS Monitoring and Assessment System) is a platform to monitor the BDS and evaluate the available system performance, servicing various users and applications with different products. It has been attached great importance to the system security,with the data security as one of its key points, in iGMAS development. In the paper, the potential risks are analyzed with the focus on data security for iGMAS based on the experience achieved in developing information systems alike to iGMAS. The analysis is made from various aspects including data communication, data transmission and verification, and data storage. Protection scheme is elaborated with the technology and management measures accounted.