Abstract: With the development of location services, people’s demand for positioning accuracy continues to increase. At present, the positioning accuracy of smart phones is only at the meter level. In 2016, Google announced that it would allow developers to obtain mobile phone the Global Navigation Satellite System (GNSS) raw observation data, and it provided support for the research on mobile phone GNSS high-precision positioning algorithms. Since the pseudorange noise acquired by smart phones is relatively large, the accuracy of single-point positioning or pseudorange differential positioning using only pseudorange is limited, and it is difficult to achieve high accuracy. Therefore, on the basis of controlling the data quality, using the data output by the intelligent terminal, the speed is solved as the initial solution to constrain the coordinates. The accuracy of the speed measurement is analyzed, and the differential positioning is orgunized combing pseudorange and carrier. The experimental results show that the accuracy of velocity measurement is about 10 cm/s, which meets the positioning requirements of participating in the calculation as an initial solution. After the static simulation dynamic test results converge, the plane accuracy is 0.35 m, and the elevation accuracy is 0.59 m.The result of dynamic test is that the plane accuracy is 0.87 m, and the elevation accuracy is 1.09 m.The overall positioning result can reach the decimeter level.