Abstract: Objectives： By integrating navigation and radar remote sensing, the global navigation satellite system (GNSS)-based forward scatter radar (FSR) system has many unique advantages, such as covert detection, low cost of netted detection, and wide coverage, demonstrating its great potential in low-altitude surveillance. To evaluate the performance of the GNSS-based FSR system in detecting the low-altitude target and estimating its parameters, an experiment was conducted at Wuhan Hannan General Airport, where this system was used to detect a low-altitude general aviation aircraft. Methods： In this field experiment, a GNSS-based multiple-input multiple-output (MIMO) FSR network was constructed using six receiving stations deployed on the ground and multiple visible GNSS satellites. After preprocessing the collected forward scattering echoes, the Doppler rate was estimated with the dechirping algorithm, and the matched filtering method was then used to extract the time instant at which the target crossed the baseline. Based on the baseline crossing time difference, the target’s three-dimensional position and motion velocity were estimated. Finally, the target motion trajectory was generated using the polynomial fitting method. Results： The results show that the GNSS-based MIMO FSR network detected that the target crossed a total of eight baselines. Moreover, compared with the target parameters obtained synchronously with the automatic dependent surveillance-broadcast (ADS-B) system, the root mean square error values of the target position estimation along the X-, Y-, and Z- axes in the local three-dimension coordinate system were 13.94 m, 8.55 m, and 8.58 m, respectively, and the estimation error of target velocity was 1.34 m/s. In addition, the generated target motion trajectory was almost consistent with the actual one provided by the ADS-B system. Conclusions： The experimental results demonstrate that the GNSS-based FSR system can achieve the low-altitude target detection, target parameter estimation, and target motion trajectory generation, and hence can be applied to the low-altitude surveillance.