In road transport, continuous high-accuracy positioning is required in real time. To ensure the proper functioning and safety of vehicular applications, integrity monitoring (IM) is needed to protect from the positioning errors under a certain alert limit (AL) with a pre-defined probability of misleading information (MI). In this study, a detailed threat model is developed for real-time kinematic (RTK) positioning application of short baselines. The model distinguishes between ambiguity-float and -fixed scenarios, and considers the influences of phase and code multipath as well as between-receiver atmospheric residuals. With the float ambiguities temporally constrained, the bias contribution that propagates with time-updated ambiguities was studied analytically for the horizontal protection level (HPL) in IM. Based on real data from both static and kinematic experiments, HPL was computed along the direction of the semi-major axis of the horizontal error ellipse. In ambiguity-float and -fixed cases, the HPL was mostly several meters and decimetres, respectively. It was found that time-propagated biases play a dominant role in the ambiguity-float HPL, and among them, phase and code multipath had in general the largest contributions. For ambiguity-fixed case, the phase multipath was found to play a dominant role in the HPL. This shows the importance of considering the biases in the RTK IM for both the ambiguity-float and -fixed scenarios. Given a horizontal alert limit (HAL) of 5 m, the availabilities of ambiguity-float solutions were low, i.e., below 50% for the static roof tests and below 5% for the kinematic road tests. For the ambiguity-fixed scenario, with HAL at 0.5 m, integrity availability was nearly 100% for the static roof tests and above 85% for the kinematic road tests.

在公路运输中，需要实时进行连续的高精度定位。为了确保车辆应用的正常运行和安全，需要完整性监控（IM），以一定的误导性信息（MI）的预定概率保护在特定警报限值（AL）下的定位错误。在本研究中，针对短基线的实时运动（RTK）定位应用开发了详细的威胁模型。该模型区分了歧义浮点场景和固定场景，并考虑了相位和代码多径以及接收者之间的大气残差的影响。在浮动模糊度受到时间限制的情况下，针对IM中的水平保护级别（HPL）进行了分析研究了随时间更新的模糊度而传播的偏差贡献。基于静态和运动学实验的真实数据，沿着水平误差椭圆的半长轴方向计算HPL。在模糊不清和固定的情况下，HPL分别分别为几米和十米。已发现时间传播的偏差在模糊浮点HPL中起主要作用，其中，相位和代码多径通常具有最大的贡献。对于解决歧义的情况，发现相位多径在HPL中起主导作用。这显示了对于不确定性浮动和固定情形都必须考虑RTK IM中的偏差的重要性。在水平警报极限（HAL）为5 m的情况下，歧义浮点解的可用性很低，即静态屋顶测试低于50％，运动路测试低于5％。