GNSS (Global Navigation Satellite System) technology is weather-resistant and can capture 3D displacement. However, it is often challenged by observation noise, especially in real-time construction monitoring. This study investigates real-time displacement monitoring of a bridge under construction based on GNSS. The proposed method uses a formulation incorporating the Robbins-Monro algorithm within Kalman filter to adaptively reduce the observation noise. The vertical displacements of a bridge under construction are estimated based on GNSS and the proposed method. The estimated displacements are compared with those by level survey.
