Editing Wide Area Augmentation System (section)

==Comparison of accuracy==
{| class="wikitable"
|+ A comparison of various radionavigation system accuracies
! System
! 95% accuracy<br /> (lateral / vertical)
! Details
|-
|[[LORAN-C]] specification
|460&nbsp;[[metre|m]] / 460&nbsp;m
|The specified absolute accuracy of the LORAN-C system.
|-
|[[Distance measuring equipment]] (DME) specification
|185&nbsp;m (Linear)
|DME is a radionavigation aid that can calculate the linear distance from an aircraft to ground equipment.
|-
|[[GPS]] specification
|100&nbsp;m / 150&nbsp;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&nbsp;m / 50&nbsp;m
|The U.S. Coast Guard reports "return to position" accuracies of 50 meters in time difference mode.
|-
|[[eLORAN]] repeatability{{citation needed|date=August 2018}}
|
|Modern LORAN-C receivers, which use all the available signals simultaneously and H-field antennas. <!-- Potential source: http://www.eu-gloria.org/2003/GNSS2003%20Loran-C%20Challenges%20GNSS.pdf -->
|-
|[[Differential GPS]] (DGPS)
|10&nbsp;m / 10&nbsp;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 [[United States Department of Defense|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&nbsp;m / 7.6&nbsp;m
|The worst-case accuracy that the WAAS must provide to be used in precision approaches.
|-
|[[GPS]] measured
|2.5&nbsp;m / 4.7&nbsp;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.<!-- Not a typo: This is NOT the NTSB! -->
|-
|WAAS measured
|0.9&nbsp;m / 1.3&nbsp;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 [[Instrument landing system#ILS categories|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.<ref>[https://books.google.com/books?id=zwmJI0I3qCMC&pg=PA279&dq=%22laas%22+autoland&hl=en Aircraft Instrumentation and Systems]. page 279 chapter "9. Aircraft Navigation Systems" section "2 Ground Based Augmentation Systems"</ref>
|}