High precision mobile mapping system has become an effective method for solving the data acquisition problem and the high precision position system is the key part of the mobile mapping system.In this paper,an embedded real-time RTK system is realized based on the FPGA and DSP architecture.The designation and realization of the hardware and the RTK algorithm are introduced in detail.The performance of the embedded RTK system was evaluated in open condition and typical complex urban conditions with 3G/4G method to transmit the differential correction datas.Results show the lagging time for most of the differential correction data is within 10 seconds in typical urban condition.The positioning precision of the single system and GPS/BDS system is also compared and it is showed that the GPS/BDS positioning method can effectively improve the visible satellite number and the positioning precision is much higher that single system.The positioning precision for the GPS/BDS system is better than 5cm which can satisfy the requirement of the mobile mapping system.