Loran for RNP 0.3 Approach: The Preliminary Conclusions of Loran Integrity Performance Panel (LORIPP)

Loran, is an attractive candidate to provide backup services for GPS because of its complementary RNAV, stratum 1 frequency stability, precise timing, and data channel capabilities. However, for Loran to be accepted as a backup navigation system for aviation, it must meet the accuracy, availability, integrity, and continuity standards for Required Navigation Performance 0.3 (RNP 0.3). The Loran Integrity Performance Panel (LORIPP) is a core team of experts assessing Loran’s potential to meet the RNP 0.3 performance. It applies engineering and safety analysis principles to build in safety as an integral part of the system design. The LORIPP is following safety analysis methods similar to those used by the WAAS Integrity Performance Panel (WIPP) to conduct a Hazardously Misleading Information (HMI) analysis on Loran. In order to properly address the RNP 0.3 accuracy, availability, integrity, and continuity requirements, many areas of development and research have been undertaken. Developments include transmitter equipment upgrades, receiver technology, and changes in operating procedures. These changes provide a new enhanced Loran (eLoran). Major areas of assessments include groundwave propagation, precipitation static, atmospheric noise, transmitter, receiver and overall system engineering. The analyses produced by these task areas are then used to determine the accuracy, availability, continuity and integrity of the enhanced Loran system. The paper shows the preliminary conclusions of the LORIPP study on Loran RNP 0.3. It also will discuss the current results from each area of investigation. Ground and flight tests have been conducted to collect data. Analysis of data for ground propagation, atmospheric noise, precipitation static and platform noise is currently being conducted and preliminary results and conclusions can be drawn. Ongoing analysis of the transmitter is conducted to determine transmitter availability and signal integrity. Other work involves an examination of skywave, continuous wave and cross rate interference. Finally, receiver algorithms are being completed that will incorporate interference f rom atmospheric noise.