Radio Spectrum Inventory: A 2010 Snapshot — Canada

Chapter 9–Aeronautical Services and Applications

9.1 Background

9.1.1 Definition of Service

Aeronautical applications are radiocommunication applications used by the civil aviation communities and government departments and agencies to establish communications between aircrafts and ground stations or provide navigational information to pilots and/or ground control centers (air traffic control towers) to ensure the safety and regularity of flights in the airspace. Due to the international nature of the aeronautical operations, the Canadian aeronautical allocations are fully harmonized with the ITU Radio Regulations.

In the context of this study addressing the frequency range 52 GHz, two aeronautical services are allocated in various bands:

  • the Aeronautical radionavigation service, a radionavigation service based on technologies, such as radars and/or radio beacons, which provide the determination of the position, velocity and/or other characteristics of an aircraft, or the obtaining of information related to these parameters, by means of the propagation properties of radio waves intended for the benefit and for the safe operation of aircraft; and
  • the Aeronautical mobile (R) service, an aeronautical mobile service reserved for communications related to safety and regularity of flight, primarily along national or international civil air routes (the capital R standing for ?On Route' to represent this specific usage).

9.1.2 Broad Description of Type of Service/Applications

The range of aeronautical radionavigation applications is wide and is dependent on the intended use, the physical characteristics of the bands used, and their interrelationship in the overall air traffic control environment.

In the range under study, applications include Instrument Landing systems (ILS), VHF Omnidirectional Radiobeacon (VOR), Distance Measurement Equipment (DME), Emergency Locator Transmitters (ELT), Anti Collision Avoidance System (ACAS), Secondary Surveillance Radar (SSR), Tactical Air Navigation systems (TACAN), JTIDS/MIDS (Joint Tactical Information Distribution System/Multifunctional Information Distribution System) Link 16, Traffic Collision Avoidance systems (TCAS), radar altimeters, microwave landing systems (MLS), Airborne Weather Radars (AWR) and airborne Doppler radars. These systems will be briefly described according to their bands of operation in the subsequent sections.

9.1.3 International and Domestic Considerations

Canada is signatory to the Convention on International Civil Aviation, known as the Chicago Convention. Consequently, Canada is an active member of the International Civil Aviation Organization (ICAO), based in Montréal. Under Annex 20 of the Chicago Convention, Canada has the responsibility to designate certain radio frequencies, within the spectrum, for use by aeronautical services and, to the greatest extent possible, keep those frequencies free from harmful interference.

To meet these responsibilities, Industry Canada established an agreement with NAV CANADA.Footnote 34 The bands identified under this agreement are in Table 9.1 below.

Table 9.1: Frequency Bands Relevant to Frequency Selection and Coordination (Agreement between Industry Canada and NAV CANADA)
Frequency (MHz) Applications
74.8-75.2 ILS, Marker Beacons
108.000-121-9875 VOR, ILS, VHF Comm
123.5875-128.8125 VHF Comm
132.0125-136.4875 VHF Comm
328.6-335.4 ILS Glide Slope
960-1215 DME, TACAN, TCAS, SSR
5030-5091 MLS

9.2 Current Allocations and Utilization

9.2.1 List of Allocated Bands

In the frequency range 52 MHz to 38 GHz, the following bands are allocated to aeronautical services in the Canadian Table of Frequency Allocations (CFTA).Footnote 35

74.8-75.2 MHz:
  • Aeronautical radionavigation service has primary status.
  • The frequency 75 MHz is assigned to marker beacons.

The frequency 75 MHz is assigned to marker beacons for use with ILS to define specific points on the approach path of aircraft. In addition, markers may also be used to mark significant points on air routes.

108-117.975 MHz:
  • Aeronautical radionavigation service has primary status.
  • The aeronautical mobile (R) service shares this band on a co-primary basis through a footnote.

The band 108-117.975 MHz is shared by multiple aeronautical applications. It is used for ILS localizer, VOR, ground-based augmentation system (GBAS) and VHF Data Link Mode 4 (VDL mode 4).

The instrument landing system (ILS) is a non-visual aid to final approach and landing. The localizer transmitter emits signals which provide azimuth guidance throughout the descent path to the runway threshold.

The VHF omnidirectional radio range (VOR) is the short-medium-range navigation aid. The basic navigation guidance derived from a VOR is a radial line of position (magnetic) with respect to a known geographic point (the VOR site).

The ground-based augmentation system (GBAS) monitors GNSS signals and broadcasts locally relevant integrity messages, pseudorange corrections and approach data via a VHF data broadcast (VDB) to aircraft.

117.975-137 MHz:
  • Aeronautical mobile on route (OR) service has primary status.
  • The use of frequency 121.5 MHz is limited to search and rescue operations.

The band 117.975-137 MHz is the main communications band for line-of-sight air-ground communications and is used at all airports, for on route, approach and landing phases of flight and for a variety of short-range tasks for general aviation and recreational flying activities (e.g. gliders and balloons).

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328.6-335.4 MHz:
  • Aeronautical radionavigation service has primary status.
  • The use of the band is limited to ILS (glide path applications).

The ultra high frequency (UHF) glide slope transmitter, operating within the frequency band from 328.6 MHz to 335.4 MHz, radiates its signals in the direction of the localizer. The term "glide path" means that portion of the glide slope that intersects the localizer. The signal provides vertical descent information for navigation.

335.4-399.9 MHz:

This band is part of the NATO 220-400 MHz band reserved for military applications. DND has various military applications in this band, such as NATO HaveQuick systems, Link 11 and NAMAR. These various applications are common among NATO countries. There is no civilian service in this frequency range.

960-1215 MHz:
  • Aeronautical radionavigation and aeronautical mobile on route (OR) services have co-primary status in the 960-1164 MHz portion.
  • Aeronautical radionavigation and radionavigation satellite services have co-primary status in the 1164-1215 MHz portion.
  • The use of the band is limited to systems that operate in accordance with recognized international standards developed by ICAO.
  • The use of band 960-215 MHz is reserved for aeronautical radionavigation service on a worldwide basis for the operation and development of airborne electronic aids to air navigation and any directly associated ground-based facilities.

The band 960-1215 MHz is the prime radionavigation band, which is used intensively, and extensively, to support a number of aviation systems, for both civil and military purposes.

The distance measuring equipment (DME) is a system for the determination of the distance between an aircraft and a ground-based DME beacon within radio line of sight, using pulse techniques and time measurement. DME/N is the standard system used for navigation. It can be co-located with VHF omnidirectional radio range (VOR) enabling the aircraft's position to be determined through a measurement of its bearing and the distance relative to the VOR/DME. Alternatively, the aircraft's position can be determined through measurement of the distances from two or three DMEs and the flight management system (FMS) equipment in the aircraft. DME/P is a precision version of DME with enhanced precision measurement capability, which is used in conjunction with MLS to provide accurate distance to touch down.

The TACAN is the military equivalent of DME, which also has a bearing capability and uses the same channel plan as for DME. JTIDS/MIDS (Joint Tactical Information Distribution System/Multifunctional Information Distribution System) Link 16 is a military radio system for the distribution of information, position location and identification between different military elements, such as aircrafts, ships and radar systems. A communication net is set up between these elements to distribute the information. JTIDS/MIDS cannot cause harmful interference to the aeronautical radionavigation service and follows a sophisticated deconfliction protocol to operate in the band.

Secondary surveillance radar (SSR) is a system for secondary surveillance radar. It is used either as a stand-alone system or co-located and synchronized with primary radar. The ground equipment is an interrogator and the aircraft equipment is a transponder responding to signals from the interrogator. All SSR installations operate on 1030 MHz for the air-to-ground reply.

The airborne collision avoidance system (ACAS) is a system for detection and avoidance of airborne conflict situations. The ACAS equipment determines which aircraft represents potential collision threats and provides appropriate display indication or advisories to the flight crew to avoid collisions. ACAS operates as a supplementary system to SSR and uses the same frequency pair of 1030 MHz by air and ground elements of SSR and ACAS is shown in figures 9.10 and 9.11.

The Universal access transceiver (UAT) is a system intended to support Automatic Dependent Surveillance–Broadcast (ADS-B) data transmission, as well as ground uplink services, such as Traffic Information Service–Broadcast (TIS-B) and Flight Information Service–Broadcast (FIS-B). UAT employs a single 1 MHz and is dedicated for transmission of airborne ADS-B reports and for broadcast of ground-based aeronautical information.

1240-1300 MHz:
  • Aeronautical Radionavigation as per Footnote 5.331

These bands are used for 23 cm (L-band) primary surveillance radar (PSR), for both on-route and terminal surveillance tasks. Modern systems employing digitized plot extraction often operate on multiple frequencies and use pulse repetition frequency (PRF) discrimination where up to four or even six frequencies may be used by a single radar spaced over a band of 100 MHz may be utilized. Co-located SSR and primary surveillance radar are often employed with combined plot extraction, electronic processing and display. Electronically generated labels displaying flight number and other data, e.g. altitude, are often added to provide a complete radar data picture.

There are 16 licensed primary surveillance radars under the Aeronautical Radionavigation, as per Footnote 5.331 to NAV CANADA. The introduction of Footnote 5.331 at WRC-03 ensured the protections of the operation of these licences.

1300-1350 MHz:
  • Aeronautical radionavigation, radiolocation and radionavigation satellite services have co-primary status.

These bands are used for 23 cm (L-band) primary surveillance radar (PSR), for both on-route and terminal surveillance tasks. Modern systems employing digitized plot extraction often operate on multiple frequencies and use pulse repetition frequency (PRF) discrimination where up to four or even six frequencies may be used by a single radar spaced over a band of 100 MHz may be utilized. Co-located SSR and primary surveillance radar are often employed with combined plot extraction, electronic processing and display. Electronically generated labels displaying flight number and other data, e.g. altitude, are often added to provide a complete radar data picture.

1559-1610 MHz:
  • Aeronautical radionavigation and radionavigation satellite services have co-primary status.
1613.8-1626.5 MHz:
  • Aeronautical radionavigation and mobile–satellite (Earth-to-Space) services have co-primary status.
  • The band 1610-1626.5 MHz is also allocated to Aeronautical mobile-satellite (R) service satellite.

The band 1559-1626.5 MHz has been allocated to aeronautical radionavigation and radionavigationsatellite for many years. A number of additional allocations have been made, including that for the radionavigation-satellite and radiodetermination-satellite and, more recently, the mobile-satellite service (Earth-to-space) in the bands above 1610 MHz. The prime civil aviation interest is now in the band 1559-1610 MHz, which will support the main frequency components of both GPS and GLONASS. A component of the European system (Galileo) will also operate in this band.

Within the sub-bands 1544-1545 MHz and 1645.5-1646.5 MHz, aviation shares this portion with MSS for AMS(R)S communications. These frequencies are used for air-ground communications over oceanic/remote areas. In continental airspace, satellite communications may be used as a supplement to VHF. The system supports voice and data for ATC or ADS purposes. AMS(R)S services will be provided by service providers for both the space segment and the ground segment. The connection to ATC centres would normally be made by landline from the ground earth station. Recent developments in the MSS community will add increased complexity in coordinating availability of frequencies for AMS(R)S due to planned deployment of a terrestrial component that will use the same frequencies. The band is heavily congested.

2700 -2900 MHz:
  • Aeronautical radionavigation service has primary status.
  • Radiolocation service has secondary status.

These bands are extensively used for primary surveillance radar (10 cm) for medium-range, on-route surveillance, and for terminal area and approach monitoring. The bands are also used by other radionavigation services (particularly maritime) and radiolocation services for national purposes on a shared basis. Civil aviation radars tend to be concentrated in the band 2700-2900 MHz is increasing.

4200-4400 MHz:
  • Aeronautical radionavigation service has primary status.
  • The band is reserved exclusively for radio altimeters installed on board aircraft and for the associated transponders on the ground.

Radio altimeters have a vital task in automated landing for flare guidance, and as the sensor component in ground proximity warning systems. The basic function of radio altimeters is to measure the aircraft's absolute height above ground level.

5000-5030 MHz:
  • Aeronautical radionavigation and radionavigation satellite services have co-primary status.
5030-5091 MHz:
  • Aeronautical radionavigation service has primary status.

The band 5030-5150 MHz is intended for the operation of the international standard system (microwave landing system) for precision approach and landing. It is not currently being used by the aeronautical radionavigation service in Canada.

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5091-5150 MHz:
  • Aeronautical radionavigation service, aeronautical mobile service, and FSS feeder links have co-primary status.

The band 5091-5150 MHz is shared between three new aeronautical mobile applications (airport surface applications, aeronautical telemetry and aeronautical security transmission) and FSS.

5150-5250 MHz:
  • Aeronautical radionavigation, fixed satellite (Earth-to-Space) and mobile (except aeronautical) (WLANS) services have co-primary status.

Originally part of the initial allocation for the development of the MLS, the band 5150-5250 MHz is now unusable for that purpose.

5350-5460 MHz:
  • Aeronautical radionavigation and aeronautical mobile services have co-primary status.
  • The use of the band is limited to airborne applications.

The band 5350-5460 MHz for airborne weather radar (a mandatory carriage item in many countries) is well established and has existed for many years. Such equipment supports the safe passage of an aircraft in the vicinity of turbulent weather conditions. It provides timely warnings of rapidly changing weather conditions as an aid to in-flight route planning. In addition, such equipment enables sustained contact with geographic features, such as shorelines as a supplement to navigational orientation.

8750-8850 MHz:
  • Aeronautical radionavigation and radiolocation services have co-primary status.
  • The use of the band is limited to airborne Doppler navigation aids.

Airborne Doppler navigation systems are widely used for specialized applications, such as continuous determination of ground speed and drift angle information of an aircraft with respect to the ground. The information is derived by measuring the Doppler shift of signals transmitted from the aircraft in several narrow beams pointed towards the surface, backscattered by the surface and received by the Doppler radar receiver.

9000-9200 MHz:
  • Aeronautical radionavigation and radiolocation services have co-primary status.
  • The use of the band by the aeronautical radionavigation service is limited to ground-based radars and to associated airborne transponders, which transmit only on frequencies in these bands and only when actuated by radars operating in the same band.
9300-9500 MHz:
  • Aeronautical radionavigation use of the band is permitted through Footnote 5.475.
  • The use of the band by the aeronautical radionavigation service is limited to airborne weather radars and ground-based radars.

These 3 cm radar bands (9000-9200 MHz and 9300-9500 MHz) are used extensively by aeronautical, maritime (land-based and shipborne) and national defence radar systems. They provide shorter range surveillance and precision functions up to a 50 km distance. In aviation, they find considerable application in precision monitoring and approach functions and in airborne weather radar (AWR) systems where their shorter wavelength is very suitable for the detection of storm clouds. In this latter role, the frequency band 9345-9375 MHz has been coordinated with other users within ITU-R as the agreed aeronautical airborne frequencies for this purpose. This band provides for a narrower beam than the airborne weather radars operating at 5.3 GHz and, therefore, provides a better resolution and less ground clutter. Seventy percent of aircraft use weather radars operating in this band to receive warning of hazardous weather. In many countries, the carriage of AWR is a mandatory requirement. AWR supports the safe passage of an aircraft in the vicinity of turbulent weather conditions. It provides timely warnings of rapidly changing weather conditions as an aid to in-flight route planning. In addition, such equipment could support sustained contact with geographic features, such as shorelines as a supplement to navigational orientation. This band is also used for airport surface detection radar.

13.25-13.4 GHz:
  • Aeronautical Radionavigation, Earth Exploration satellite (active) and Space Research services have co-primary status.
  • The use of the band is limited to Doppler navigations aids.

Airborne Doppler navigation systems are widely used for specialized applications, such as continuous determination of ground speed and drift angle information of an aircraft with respect to the ground. The information is derived by measuring the Doppler shift of signals transmitted from the aircraft in several narrow beams pointed towards the surface, backscattered by the surface and received by the Doppler radar receiver.

15.4-15.7 GHz:
  • Aeronautical Radionavigation service has primary status.
  • Sub band 15.43-15.63 GHz shared on a co-primary basis with Fixed Satellite (earth-to-space).

An important civil use of this band is for airport surface detection equipment (ASDE) for operational control of aircraft and vehicle ground movement at airports. This is an expanding requirement, as congestion at airports increases and ground manœuvering areas begin to saturate. Another civil use is that of height and obstruction measurement using radar techniques. This use is presently limited for general application to smaller aircraft operating into secondary and temporary landing areas.

The band 15.5-15.7 GHz is also used for airborne weather and ground mapping radars. These systems support the safe passage of an aircraft in the vicinity of turbulent weather conditions. It provides timely warnings of rapidly changing weather conditions as an aid to in-flight route planning. In addition, such equipment could support sustained contact with geographic features, such as shorelines as a supplement to navigational orientation. The band offers the possibility for compact airborne systems which are lightweight and have small antenna dimensions. High definition radar and precision landing systems are some examples of applications.

Band Plans and Technical/Regulatory Requirements

The regulatory requirements are generally established by international bodies such, as the ITU-R and the IACO due to the global nature of the various aeronautical applications. They are adopted by domestic civil aviation agencies. In Canada, Transport Canada regulates the implementation of aeronautical systems.

The technical requirements are developed either by ICAO or various regional technical groups, such as the Radio Technical Committee for Aeronautics (RTCA) and the European Organization for Civil Aviation Equipment (EUROCAE).

Industry Canada has only one regulatory standard setting out requirements for the certification of radio transmitters and receivers in the aeronautical mobile (R) service operating in the band 117.975-137 MHz for the purpose of communication.

Aeronautical Service use from 52  MHz to 38GHz (for additional information, refer to Annex 1):
Aeronautical Service use from 52 MHz to 38 GHz (for additional information, refer to Annex 1): [Description of Figure]

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9.3 Spectrum Inventory and Analysis

The national air navigation system:

While aeronautical services are spread in multiple allocations and various applications, as shown in the above section, there is a common trend, i.e. the various applications are the overlays of a common system, the air navigation system (ANS). The ANS manages the circulation of all aircrafts and ensures the safety of all domestic, international, civilian and military flights. Domestically, the responsibility for this system is shared by Transport Canada and NAV CANADA. In the military domain, DND is the responsible department.

The bands used for the ANS are described in Table 9.1 above. It has to be noted that they are used simultaneously during various phases of the flight of aircrafts, such as take-off, landing, transit, final approach, at the airport, etc.

The following map shows the location of all airports in Canada.

Figure 9.1–Location of Airports in Canada
Figure 9.1–Location of Airports in Canada [Description of Figure 9.1]

Results of an analysis of frequency assignments are shown in Table 9.2 below.

Table 9.2
Frequency bands Applications Numbers of Assignments Major Users
74.8-75.2 MHz ILS, Marker Beacons 0 None. Markers beacons have been decommissioned.
108-117 MHz VOR, ILS, VHF Comm 325 NAV CANADA, DND
117-137 MHz VHF Comm 10322 NAV CANADA, DND, airports operators, provincial governments, aircraft manufacturers, aircraft operators
328.6-335.4 MHz ILS Glide Slope 164 NAV CANADA
960-1164 MHz DME, TACAN, TCAS, SSR 668 NAV CANADA, DND
1164-1215 MHz DME, TACAN, TCAS, SSR, JTID, MIDS 115 NAV CANADA, DND
5000-5091 MHz 10 DND, localized use
5091-5150 MHz MLS 0 No MLS
5150-5250 MHz 0 No aeronautical use

The geographical distribution of the frequency assignments in relation to the airport locations is shown in the figures 9.2 to 9.7 below.

Figure 9.2–Band 108-117 MHz
This map shows the geographical distribution of frequency assignments in the 108-117 MHz band across Canada. [Description of Figure 9.2]
Figure 9.3–Band 108-117 MHz with Airports
This map shows the geographical distribution of frequency assignments in the 108-117 MHz band, in relation to the airport locations. [Description of Figure 9.3]
Figure 9.4–Band 117-137 MHz
This map shows the geographical distribution of frequency assignments in the 117 - 137 MHz band across Canada. [Description of Figure 9.4]
Figure 9.5–Band 117-137 MHz with Airports
This map shows the geographical distribution of frequency assignments in the 117 - 137 MHz band, in relation to the airport locations. [Description of Figure 9.5]
Figure 9.6–Band 960-1164 MHz
This map shows the geographical distribution of frequency assignments in the 117 - 137 MHz band, in relation to the airport locations. [Description of Figure 9.6]
Figure 9.7–Band 960-1164 MHz with airports
This map shows the geographical distribution of frequency assignments in the 960 - 1164 MHz band, in relation to the airport locations. [Description of Figure 9.7]

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Observations:

The major aeronautical bands (108-137 and 960-1164 MHz), which are part of the ANS, are heavily used by the aeronautical communities and, in particular by the two major air navigation system operators: DND and NAV CANADA.

Two bands (74.8-75.2 MHz and 5000-5150 MHz) are underutilized by aeronautical services. The band 74.8-75.2 MHz represents 0.4 MHz of spectrum. The 5000-5150 MHz band was identified originally for the deployment for Microwave Landing Systems (MLS). However, this band has, in recent years, been the subject of close attention by other ITU radio services seeking worldwide exclusive spectrum. The very long delay in implementing the MLS and the prospect of GNSS offering equivalent capability have accelerated this attention and have led to new allocations to non-aeronautical radionavigation uses for the frequencies in the band 5150-5250 MHz and the band 5091-5150 MHz. An allocation to the AM(R)S in the band 5091-5150 MHz (MLS extension band), limited to airport surface operations, was agreed at WRC-07. This is a shared allocation with the aeronautical radionavigation service (MLS), fixed satellite service (FSS), aeronautical mobile telemetry (AMT) and an aeronautical security (AS) application intended for the provision radiocommunication used in response to unlawful interruption of aircraft operations.

Other related aeronautical bands:

Table 9.3
Frequency bands Applications Numbers of Assignments Major Users
335-399.9 MHz Military applications 1555 DND
1300-1370 MHz Primary radars 523 DND, NAV CAN
2700-2900 MHz Airport surveillance Radars 4 DND
4200-4400 MHz Radio altimeters 0 Radio altimeters are installed on aircrafts and are not domestically licensed
5350-5460 MHz Airborne and ship radars 2 DND, ship radars
Not domestically licensed.
8750-8850 MHz Radar applications
9000-9500 MHz Radar applications 67 DND, Coast Guard Canada
13.25-13.4 GHz Airborne radar applications 26 DND
15.4-15.7 GHz Airborne radar applications 27 DND
Observations:

The bands addressed are generally radar applications, either shipborne or airborne. As such, the data would provide only domestic terrestrial radar frequency assignments. Radio altimeters in the band 4200-4400 MHz are used in large body aircraft, used by the airline carriers. On each aircraft, there are up to three radio altimeters operating during a flight, particularly during take-off and landing. This is also the case for radar applications in the bands 13.25-13.5 GHz and 15.4-15.7 GHz.

The band 335-399.9 MHz is part of the NATO band 220-400 MHz. As shown, it is heavily used by military applications.

9.4 Trend Analysis

A trend analysis based on the numbers of assignment would not be representative of the aeronautical services' spectrum usage. The various systems and applications take years in development and have to meet a very demanding regulatory environment. Once the systems are deployed either at airports or included in the avionics of aircrafts, their lifespan can be several decades.

9.5 Conclusion

Based on an analysis of the Department's current database, the status of the aeronautical services both domestically and internationally, an evaluation of the major users and the international activities of ITU and ICAO, the following conclusions on the use of the spectrum by aeronautical services can be drawn:

  • Aeronautical allocations are international in nature. The majority of the aeronautical bands are part of, either directly or indirectly, the national air navigational and air traffic management systems. The technical and regulatory requirements are developed in international fora.
  • Canada is bound by a treaty to designate certain radio frequencies, within the spectrum, for use by aeronautical services and, to the greatest extent possible, keep those frequencies free from harmful interference.
  • Multiple bands are used simultaneously during a flight. As such, consideration of aeronautical bands must be taken as a whole, not on a per band basis.

Footnotes

  1. 34 back to footnote reference 34 Agreement Between Her Majesty The Queen in Right of Canada as represented by the Minister of Industry and NAV CANADA regarding Radio Frequency Spectrum Management, November 1, 2007. http://www.ic.gc.ca/eic/site/smt-gst.nsf/eng/h_sf06295.html.
  2. 35 back to footnote reference 35 Details of the applications are extracted from ICAO doc 9718-AN 957 Handbook on Radio Frequency Specturm Requirements for Civil aviation, 5th edition 2009 (unedited).
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