GPS在探地雷达探测城市道路塌陷隐患中的应用研究

在城市道路塌陷隐患探测中,回溯定位探地雷达剖面中病害异常的现场位置是对其进行复测验证及处治修复的关键.测距轮属于相对定位技术,具有难以消除的累积误差,且探地雷达剖面越长,其累积误差越大,回溯定位病害异常的现场位置越难,而GPS测量定位属于绝对坐标定位技术,没有累积误差,但在复杂的城市环境中,其干扰因素较多,测量误差较大,影响病害现场回溯定位的精度和准确性.联合采用测距轮和GPS对探地雷达进行跟踪测量定位,测距轮按照固定道间距触发探地雷达和GPS同步采集、同步存储,使每一道探地雷达数据与GPS经纬度坐标一一对应、彼此关联、相互追溯;通过绘制GPS路径轨迹,直观形象展示探地雷达实测剖面的测线位置及其工作量完成情况;采用移动平均法对GPS原始数据进行平滑去噪处理,修正测量误差,消除局部突变点,使GPS路径轨迹更平顺,更符合探地雷达检测车实际行驶的路径轨迹,由此计算得到的路径轨迹长度稳定性更高、一致性更好,更符合探地雷达实测剖面长度,同时可以有效提高病害现场回溯定位的精度,显著加快病害异常点加密复测验证工作进度.

Application research of GPS in urban road collapse detection by GPR

In the detection of urban road collapse hidden danger,it is very important to retrospectively locate the disease site location of Ground Penetrating Radar(GPR)profile for retesting and repairing.Range wheel is relative positioning technology,which has cumulative errors that are difficult to eliminate.The longer the profile,the greater the cumulative errors.GPS positioning is absolute coordinate positioning technology without cumulative errors.However,in complex urban environment,its measurement errors are large,which will seriously affect the accuracy of disease site retrospective positioning.The range wheel and GPS are used to track and locate the ground penetrating radar.The range wheel triggers the synchronous acquisition and storage of the ground penetrating radar and GPS according to the fixed track distance,so that the ground penetrating radar data at the sampling point corresponds to and correlates with the GPS spatial coordinates one by one.By plotting the GPS path trajectory,the line position and workload of the ground penetrating radar measured profile can be intuitively understood.The moving average method is used to smooth and denoise the original GPS data and correct the local abrupt points,so that the GPS path trajectory is smoother and more in line with the actual trajectory of the ground penetrating radar vehicle.The trajectory length calculated from this method is more stable and consistent,more in line with the measured profile length of the ground penetrating radar,and can effectively improve the backtracking of the disease site.The accuracy of positioning significantly accelerates the progress of field encrypted re-examination and verification of disease abnormal points.