Comparison of Accuracy
| System | 95% Accuracy (Lateral / Vertical) |
Details |
|---|---|---|
| LORAN-C Specification | 460 m / 460 m | The specified absolute accuracy of the LORAN-C system. |
| Distance Measuring Equipment (DME) Specification | 185 m (Linear) | DME is a radionavigation aid that can calculate the linear distance from an aircraft to ground equipment. |
| GPS Specification | 100 m / 150 m | The specified accuracy of the GPS system with the Selective Availability (SA) option turned on. SA was employed by the U.S. Government until May 1, 2000. |
| LORAN-C Measured Repeatability | 50 m / 50 m | The U.S. Coast Guard reports "return to position" accuracies of 50 meters in time difference mode. |
| eLORAN Repeatability | Modern LORAN-C receivers, which use all the available signals simultaneously and H-field antennas. | |
| Differential GPS (DGPS) | 10 m / 10 m | This is the Differential GPS (DGPS) worst-case accuracy. According to the 2001 Federal Radionavigation Systems (FRS) report published jointly by the U.S. DOT and Department of Defense (DoD), accuracy degrades with distance from the facility; it can be < 1 m but will normally be < 10 m. |
| Wide Area Augmentation System (WAAS) Specification | 7.6 m / 7.6 m | The worst-case accuracy that the WAAS must provide to be used in precision approaches. |
| GPS Measured | 2.5 m / 4.7 m | The actual measured accuracy of the system (excluding receiver errors), with SA turned off, based on the findings of the FAA's National Satellite Test Bed, or NSTB. |
| WAAS Measured | 0.9 m / 1.3 m | The actual measured accuracy of the system (excluding receiver errors), based on the NSTB's findings. |
| Local Area Augmentation System (LAAS) Specification | The goal of the LAAS program is to provide Category IIIC ILS capability. This will allow aircraft to land with zero visibility utilizing 'autoland' systems and will indicate a very high accuracy of < 1 m. |
Read more about this topic: Wide Area Augmentation System
Famous quotes containing the words comparison and/or accuracy:
“From top to bottom of the ladder, greed is aroused without knowing where to find ultimate foothold. Nothing can calm it, since its goal is far beyond all it can attain. Reality seems valueless by comparison with the dreams of fevered imaginations; reality is therefore abandoned.”
—Emile Durkheim (1858–1917)
“In everything from athletic ability to popularity to looks, brains, and clothes, children rank themselves against others. At this age [7 and 8], children can tell you with amazing accuracy who has the coolest clothes, who tells the biggest lies, who is the best reader, who runs the fastest, and who is the most popular boy in the third grade.”
—Stanley I. Greenspan (20th century)