In which mode does the high precision positioning (HPR) system measure only ranges?

The high precision positioning (HPR) system operates in ultra-short baseline mode primarily by measuring only ranges. This method relies on the use of closely spaced transceivers to measure the distance (or range) between the vessel and reference points on the seabed or other platforms. In ultra-short baseline systems, the accuracy of positioning is significantly enhanced due to the short distances involved, which minimizes complications such as multipath errors and delays caused by signal propagation.

In contrast, other modes such as long baseline involve measuring angles in addition to ranges to derive position, global positioning utilizes satellite signals that provide location data without the need for measuring distances locally, and real-time kinematic technology employs differential GPS techniques that also measure phase shifts rather than relying solely on ranges. Thus, the ultra-short baseline is unique in its approach to high precision positioning by focusing exclusively on the measurement of ranges.