重力矢量测量包含重力方向信息(即垂线偏差),对确定大地水准面具有重要意义。为了获得海洋重力扰动矢量的水平分量，该文提出了一种基于捷联惯导系统/全球导航卫星系统(SINS/GNSS)组合系统确定海洋重力扰动矢量水平分量的两步法。首先，利用捷联惯导算法和卡尔曼滤波用于加速度计偏差和姿态误差角的估计和补偿。然后，基于精确估计的加速度计偏差和姿态角误差，给出了重力扰动矢量水平分量的计算方程。将重力扰动矢量水平分量的模型用二阶马尔可夫随机过程描述，将其与加速度计的偏差分离，用正向-平滑卡尔曼滤波精确估计重力扰动的水平分量。船载试验数据离线计算表明,海洋重力扰动矢量水平分量的内符合精度优于2 mGal(1 Gal=1 cm/s2)。

The gravity vector measurement contains information about the gravity direction (i.e., the deflection of the plumb line), which is crucial for determining the geoid. To obtain the horizontal component of oceanic gravity disturbance vector, a two-step method based on the strapdown inertial navigation system/global navigation satellite system(SINS/GNSS) combined system is proposed for determining the horizontal component of the oceanic gravity disturbance vector. Firstly, the strapdown inertial navigation algorithm and Kalman filter are used to estimate and compensate for accelerometer bias and attitude angle errors. Then, based on the accurately estimated accelerometer bias and attitude angle errors, the calculation equation of the horizontal component of the gravity disturbance vector is presented. The model of the horizontal component of the gravity disturbance vector is described by using a second-order Markov random process and separated from the bias of the accelerometer. The forward-smoothing Kalman filter is used to accurately estimate the horizontal component of the gravity disturbance. The offline calculation of ship-borne test data shows that the internal coincidence accuracy of the horizontal component of the oceanic gravity disturbance vector is better than 2 mGal(1 Gal=1 cm/s2).