report of the action team on global navigation satellite systems (gnss)

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Table 1-6. Positioning and Timing Accuracy StandardAccuracy StandardGlobal Average Positioning Domain• ≤ 13 meters 95% All-in-ViewHorizontal Error (SIS Only).• ≤ 22 meters 95% All-in-View VerticalError (SIS Only).Worst Site Positioning Domain• ≤ 22 meters 95% All-in-ViewHorizontal Error (SIS Only).• ≤ 77 meters 95% All-in-View VerticalError (SIS Only).Time Transfer Accuracy40 nanoseconds time transfer error 95% <strong>of</strong> time(SIS Only).Conditions and Constraints• Defined for position solution meeting<strong>the</strong> representative user conditions.• Standard based on a measurementinterval <strong>of</strong> 24 hours averaged over allpoints within <strong>the</strong> service volume.• Defined for position solution meeting<strong>the</strong> representative user conditions.• Standard based on a measurementinterval <strong>of</strong> 24 hours for any pointwithin <strong>the</strong> service volume.• Defined for time transfer solutionmeeting <strong>the</strong> representative userconditions.• Standard based on a measurementinterval <strong>of</strong> 24 hours averaged over allpoints within <strong>the</strong> service volume.GPS Status and Problem Reporting Standard47. The United States Government provides notification <strong>of</strong> changes in constellationoperational status that affect <strong>the</strong> service being provided to GPS users, or if <strong>the</strong> United StatesGovernment anticipates a problem in supporting performance standards established in thisdocument. The current mechanism for accomplishing this notification is through <strong>the</strong> Notice:Advisory to Navigation Users (NANU). NANUs are a primary input in <strong>the</strong> generation <strong>of</strong> GPSrelatedNotice to Airmen (NOTAM) and United States Coast Guard Local Notice to Mariners(LNM). Most outages affect both PPS and SPS users. However, since <strong>the</strong> GPS Control Segmentcurrently monitors PPS, not SPS, in near real-time, notification <strong>of</strong> SPS unique service disruptionsmay be delayed. Since NANUs are currently tailored to PPS outages, notification <strong>of</strong> SPS uniqueoutages may require <strong>the</strong> use <strong>of</strong> <strong>the</strong> general “free text” NANU vice a tailored template.48. In <strong>the</strong> case <strong>of</strong> a scheduled event affecting service provided to GPS users, <strong>the</strong> UnitedStates Government will issue an appropriate NANU at least 48 hours prior to <strong>the</strong> event. In <strong>the</strong>case <strong>of</strong> an unscheduled outage or problem, notification will be provided as soon as possible after<strong>the</strong> event.49. The Block II satellites are designed to provide reliable service over a 7.5 - to 10-yeardesign life, depending on <strong>the</strong> production version, through a combination <strong>of</strong> space qualified parts,multiple redundancies for critical subsystems, and internal diagnostic logic. The Block II satelliterequires minimal inter<strong>action</strong> with <strong>the</strong> ground and allows all but a few maintenance activities to beconducted without interruption to <strong>the</strong> ranging signal broadcast. Periodic uploads <strong>of</strong> data tosupport navigation message generation are designed to cause no disruption to <strong>the</strong> SPS rangingsignal, although Block II/IIA satellites may experience a 6 to 24 second disruption upon transitionto <strong>the</strong> new upload.14
50. The GPS Control Segment (CS) is comprised <strong>of</strong> four major components: a MasterControl Station (MCS), Backup Master Control Station (BMCS), four ground antennas, and sixmonitor stations. The MCS at Schriever Air Force Base, Colorado, is <strong>the</strong> central control node for<strong>the</strong> GPS satellite constellation. Operations are maintained 24 hours a day, seven days a weekthroughout each year.51. The CS's four ground antennas provide a near real-time Telemetry, Tracking, andCommanding (TT&C) interface between <strong>the</strong> GPS satellites and <strong>the</strong> MCS. The six monitorstations provide near real-time satellite ranging measurement data to <strong>the</strong> MCS and support nearcontinuousmonitoring <strong>of</strong> constellation performance. The current CS monitor stations provideapproximately 93% global coverage, with all monitor stations operational, with a 5° elevationmask angle. The actual elevation angle that a monitor station acquires any given satellite variesdue to several external factors.52. SPS performance standards are based on signal-in-space performance. Contributions <strong>of</strong>ionosphere, troposphere, receiver, multipath or interference are not included.Predictable Accuracy53. The United States Government commits to maintaining <strong>the</strong> Position Dilution <strong>of</strong> Precision(PDOP) in accordance with <strong>the</strong> following tolerances: Position Dilution <strong>of</strong> Precision AvailabilityStandard: PDOP Availability Standard = 98% global Position Dilution <strong>of</strong> Precision (PDOP) <strong>of</strong> 6or less = 88% worst site PDOP <strong>of</strong> 6 or less. In support <strong>of</strong> <strong>the</strong> service availability standard, 24operational satellites must be available on orbit with 0.95 probability (averaged over any day).54. At least 21 satellites in <strong>the</strong> 24 nominal plane/slot positions must be set healthy andtransmitting a navigation signal with 0.98 probability (yearly averaged). The United StatesGovernment’s commitments for maintaining PDOP and constellation SPS SIS URE result insupport for a service availability standard as presented in Table 1-3. The SPS Performancecombines a constellation availability <strong>of</strong> 24 operational satellites at 95% probability.Service Availability55. The percentage <strong>of</strong> time over a specified time interval that <strong>the</strong> predicted position accuracyis less than a specified value for any point within <strong>the</strong> service volume.Service Availability Standard56. The United States Government commits to maintaining <strong>the</strong> Position Dilution <strong>of</strong> Precision(PDOP) in accordance with <strong>the</strong> following tolerances:Position Dilution <strong>of</strong> Precision Availability Standard:57. PDOP Availability Standard> 98% global Position Dilution <strong>of</strong> Precision (PDOP) <strong>of</strong> 6 or less;> 88% worst site PDOP <strong>of</strong> 6 or less.15
Page 1 and 2: REPORT OF THE ACTION TEAM ONGLOBAL
Page 3 and 4: This document has not been formally
Page 5 and 6: CONTENTSIntroduction ..............
Page 7 and 8: REPORT OF THE ACTION TEAMON GLOBAL
Page 9 and 10: Product4. The product of</s
Page 11 and 12: II.OVERVIEW OF PLANNED AND EXISTING
Page 13 and 14: virtually every facet of</s
Page 15 and 16: 27. Time and frequency disseminatio
Page 17 and 18: Service Availability Standard39. Th
Page 19: Table 1-4. Service Reliability Stan
Page 23 and 24: Service Availability Standard62. Th
Page 25 and 26: 71. The GPS Navigation Message cons
Page 27 and 28: the Board, mainly
Page 29 and 30: • Vertical :• Velocity:• User
Page 31 and 32: • The network of
Page 33 and 34: 126. The EU and ESA have concluded
Page 35 and 36: • The Search and Rescue Service (
Page 37 and 38: invitation to tender to this effect
Page 39 and 40: 2. EGNOS169. As previously mentione
Page 41 and 42: 183. Three phases have been identif
Page 43 and 44: an air navigation service dedicated
Page 45 and 46: • Aviation: a representative desi
Page 47 and 48: 222. The information is openly avai
Page 49 and 50: 234. The United Nations Office for
Page 51 and 52: • Provide consultancy and advice
Page 53 and 54: 255. Methods to compare distant clo
Page 55 and 56: measurements are used to evaluate <
Page 57 and 58: market can begin to develop. That a
Page 59 and 60: Nations and voluntary contributions
Page 61 and 62: IV.GNSS APPLICATIONSA. General appl
Page 63 and 64: 317. Agricultural applications incl
Page 65 and 66: 326. The regional activity in <stro
Page 67 and 68: GNSS SBAS-WAAS trials in th
Page 69 and 70: 356. Other activit
Page 71 and 72:
with respect to the</strong
Page 73 and 74:
379. Argentina has at present a “
Page 75 and 76:
Brazilian Continuous GPS Network (R
Page 77 and 78:
all mapping-related works in <stron
Page 79 and 80:
monitoring, national reference <str
Page 81 and 82:
Programs: B.Sc/M.Sc/Ph.D. in geomat
Page 83 and 84:
• University of
Page 85 and 86:
V. NEEDS AND CONCERNS OF DEVELOPING
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Surveying, Mapping, Land Use• Pre
Page 89 and 90:
include Special Implementation Proj
Page 91 and 92:
VI.EXISTING TRAINING OPPORTUNITIES
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465. Many other GN
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• Theory and practice of<
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D. GNSS training opportunities <str
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VII.INSTITUTIONAL MODELS FOR INTERN
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Environment Programme (UNEP), and <
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appropriate national security reaso
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VIII.RECOMMENDATIONS541. A number <
Page 107 and 108:
for Outer Space Affairs, developmen
Page 109 and 110:
• Develop the sk
Page 111 and 112:
Recommendation 2. The development <
Page 113 and 114:
583. The need to develop th
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589. Project 2:Pilot Projects (4 pr
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Annex I: Indian universities, resea
Page 119 and 120:
University/researchinstitute/compan
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Annex III: Italian universities and
Page 123 and 124:
Annex IV: Italian non-governmental
Page 125 and 126:
Annex IV: Italian non-governmental
Page 127 and 128:
APPENDIXList of we
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report of the action team on global navigation satellite systems (gnss)

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