Positioning and telemetry from ROV survey ARTofMELT2023/1_23-10 on 2023-06-07, survey 1

The horizontal position of the remotely operated vehicle (ROV) during the ARTofMELT2023 expedition in May and June 2023 was measured using an acoustic Long Base Line (LBL) positioning system (LinkQuest Pinpoint) with an operating frequency of 26.77-44.62kHz. It consists of a transceiver onboard the ROV and 3 transponders which were deployed on 5 m long chains through the drifting ice cover at different horizontal distances from the ROV ice access hole. Due to the high latitude and glitches in the Pinpoint software's coordinate conversions, the surveys were virtually moved and 'fake' geographic positions centered around 1°N/1°E were used. The survey track was smoothed using a Kalman filter from initial acoustic fixes and cleaned for most obvious outliers. This calibration result in a floe-fixed, relative coordinate system (distance, relative, X and distance, relative, Y) with the origin (X=0 m, Y=0 m) at the ROV hole. The final position was recorded in the SPOT.ON survey systems software (OceanModulesTM). A quality flag for the position is introduced based on the time to the closest fix with "1" indicating good positon (fix reached <= 3s), "2" medium position (fix reached > 3s & <= 5s), and "3" bad position (fix reached > 5s). Depending on the scientific aim, a position with quality flag "3" can still be useful. The ROV depth was measured by an integrated pressure sensor (Keller A-21Y, Keller AG) included in the main electronics housing of the ROV and calibrated to 0 during pre-survey procedures, when the top side of the ROV was at the same level as the water surface. The accuracy of the sensor is 0.10 m. ROV attitude (roll, pitch, heading) was measured with an onboard inertial measuring unit (Microstrain) with three axis accelerometer, magnetometer, and gyroscope.2023年5月至6月的ARTofMELT2023科考航次中，遥控水下机器人（remotely operated vehicle, ROV）的水平位置采用声学长基线（Long Base Line, LBL）定位系统（LinkQuest Pinpoint）进行测量，该系统工作频率范围为26.77~44.62kHz。该系统包含ROV搭载的收发单元，以及3台应答器；应答器通过长5米的链绳部署于浮冰盖下方，与ROV的冰上出入孔保持不同水平间距。由于科考区域处于高纬度地带，且Pinpoint软件的坐标转换功能存在异常，研究团队对原始测量数据进行了偏移修正，并采用了以1°N/1°E为中心的“虚拟”地理坐标。随后，研究人员使用卡尔曼滤波器（Kalman filter）对初始声学定位结果进行轨迹平滑处理，并剔除了绝大多数明显的异常值。此次校准最终建立了以ROV冰上出入孔为原点（X=0 m, Y=0 m）的浮冰固定相对坐标系（相对距离、相对X轴与相对Y轴）。最终的位置数据记录于SPOT.ON测量系统软件（OceanModulesTM）中。研究团队引入了位置质量标记规则，基于最近一次有效定位的耗时进行分级：标记“1”代表定位质量良好（定位完成耗时≤3秒），“2”代表定位质量中等（3秒<定位完成耗时≤5秒），“3”代表定位质量较差（定位完成耗时>5秒）；根据具体科学研究目标，带有“3”标记的位置数据仍具备使用价值。ROV的水深由集成于其主电子舱的压力传感器（Keller A-21Y, Keller AG）测得；该传感器在航次前预校准流程中已完成零点标定，此时ROV顶部与水面处于同一水平面，传感器精度为0.10米。ROV的姿态参数（横滚角、俯仰角、航向角）由搭载的惯性测量单元（inertial measuring unit）测得，该单元集成了三轴加速度计、磁强计与陀螺仪。