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ViaSat-1 Ka-band Satellite
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ViaSat uses this spectrum for its Ka-band direct-to-consumer broadband Internet service, under the trade name "exede." The ViaSat-1 satellite was launched from Baikonur on October 19th, 2011, and entered commercial service on January 16th, 2012.
The satellite downlinks and uplinks use both right- and left-hand circular polarizations from a geostationary orbit at 115.1 deg west longitude.
ViaSat-1 has 72 user beams, of which 63 serve the U.S. Nine beams serve Canada.
User terminals utilize a dish of 0.695 m (about 27") maximum diameter, and will uplink using carriers between 625 kHz and 10 MHz wide using max EIRP between 47.2-50.3 dBW. The antennas have transmit gain of about 44 dBi, and receive gain of about 40 dBi. ViaSat is authorized for up to 250,000 such terminals in the continental U.S., operating under the callsign E120026.
The satellite downlink bandwidth is between 52-416 MHz.
As of March 2013, ViaSat claimed 512,000 customers. They have also announced plans for the ViaSat-2 satellite, to be launched in mid-2016, which will have 2.5 times the capacity of ViaSat-1, and will have a single beam that covers the continental U.S., Mexico, most of Canada, portions of Central America and the Caribbean, and the North Atlantic over to the western edge of Europe.
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Frequency Bands |
| Band | Use | Service | Table |
| 18.3 - 18.8 GHz | ViaSat-1 downlink | Fixed-satellite (space-to-Earth) | N |
| 18.8 - 19.3 GHz | ViaSat-1 downlink | Fixed-satellite (space-to-Earth) | N |
| 19.7 - 20.2 GHz | ViaSat-1 downlink | Fixed-satellite (space-to-Earth) | N |
| 28.1 - 28.6 GHz | ViaSat-1 uplink | Fixed-satellite (Earth-to-space) | N |
| 28.6 - 29.1 GHz | ViaSat-1 uplink | Fixed-satellite (Earth-to-space) | N |
| 29.5 - 30 GHz | ViaSat-1 uplink | Fixed-satellite (Earth-to-space) | N |
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Soil Moisture Active Passive (SMAP) Satellite
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The Soil Moisture Active Passive (SMAP) satellite is a planned NASA satellite mission to monitor soil moisture around the globe. It is planned for launch in 2014.
As its name implies, the Soil Moisture Active Passive (SMAP) satellite uses active and passive radio systems to measure soil moisture around the globe. The spacecraft is in a sun-syncronous orbit that passes overhead of its target areas around 6 AM and 6 PM, approximately every 3 days at the equator and every 2 days at high latitudes.
SMAP's sensors can determine soil moisture down to a depth of approximately 5-10 cm. The active radar provides approximately 3 km resolution on the ground, using a 6 m antenna and measuring reflections in HH, VV, and HV polarization modes. The radar works in frequency hopping mode to avoid interference to and from aviation radars that operate in the same band. The instantaneous signal from the radar consists of two separate signals each of ~1.4 MHz bandwidth, separated by 5 MHz. It pulses every ~354 microseconds, for a duration of ~10-20 microseconds per pulse. The radar transmit power (not EIRP) is a few hundred watts.
SMAP will operate in a circular orbit of 670 km altitude. The ground footprint of the radar is approximately 1000 km. Resolution of the radar in low-resolution mode is approximately 40 km, and in high-resolution mode the resolution is approximately 3 km.
Soil moisture data can be used for improving numerical weather prediction, including seasonal climate prediction and rainfall prediction.
Like the European SMOS satellite, it is anticipated that SMAP's passive sensor will be subject to illegal RFI in the passive-only 1400-1427 MHz band.
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Frequency Bands |
| Band | Use | Service | Table |
| 1200 - 1300 MHz | SMAP active radar | Earth Exploration-satellite (active) | F |
| 1400 - 1427 MHz | SMAP passive radiometer | Earth Exploration-satellite (passive) | F |
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Proposed Air-Ground Broadband for Passengers Aboard Aircraft
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The FCC has proposed the establishment of a new air-ground mobile broadband service in the 14.0-14.5 GHz band. The current primary allocation is to the Fixed Satellite Service. The FCC proposes to achieve compatibility through “spatial diversity” rules, which would limit the directions in which antennas can point. Since the 14.0-14.5 GHz band is used for sending transmissions from the Earth towards satellites orbiting over the equator, U.S. earth stations all point south, more or less. Antennas in the proposed system would point north (in the case of ground stations) or downwards (in the case of the antennas on the aircraft), which should reduce their interference with satellite users.
The following information is edited from the FCC's Notice of Proposed Rulemaking,FCC 13-66:
We propose to establish a new, terrestrial-based air-ground mobile broadband service with aircraft in the 14.0-14.5 GHz band. The service would provide multi-gigabit broadband connectivity to aircraft flying within the contiguous United States. The service is intended for the business and personal use of passengers aboard aircraft, and will have no role in aeronautical operations or as a safety of life and property service.
The 14.0-14.5 GHz band is allocated on a primary basis to the FSS as an uplink (Earth-to-space) band for geostationary orbit (GSO) FSS operations. The air-ground mobile broadband service would operate on a secondary basis to GSO satellite systems and future non-geostationary orbit (NGSO) satellite systems, and on a co-secondary basis with the National Aeronautics and Space Administration (NASA) Tracking and Data Relay Satellite System (TDRSS) that operates under a Federal Fixed Service (FS) and Mobile Service (MS) allocation. In addition to coordinating with NASA TDRSS in the 14.0-14.2 GHz band, we propose that air-ground mobile broadband would also be required to coordinate with Radio Astronomy Service (RAS) users in the 14.47-14.5 GHz band, in accordance with the procedures set forth for other services in this band. To implement this service, we propose to amend Part 2 of the rules to add a secondary allocation in the non-Federal Aeronautical Mobile Service (AMS) for air-ground mobile broadband in the 14.0-14.5 GHz band.
We propose that under the rules we implement for the 14.0-14.5 GHz band to support the new allocation, we would require a licensee to use this spectrum for air-ground mobile broadband only. We also seek comment regarding the appropriate regulatory framework for the proposed provision of service. We seek comment on our proposal to classify the services as Commercial Mobile Radio Service (CMRS) given the proposed air-ground use of the spectrum. With respect to whether and how to apportion the spectrum, we seek comment on Qualcomm’s proposal to create two 250 megahertz licenses as well as on alternate approaches such as licensing the entire 500 megahertz of spectrum to a single licensee or dividing the spectrum into more than two blocks. Given the proposed air-ground use of the band, we propose to license the spectrum on a nationwide basis. We also seek comment on whether to adopt an open eligibility standard and whether to adopt any specific aggregation limits applicable to the initial licensing of the band.
To the extent that we adopt a geographic licensing scheme for the 14.0-14.5 GHz band, and permit the filing of mutually exclusive applications, we seek comment on a number of proposals relating to competitive bidding. We propose that the Commission conduct an auction in conformity with the general competitive bidding rules set forth in Part 1, Subpart Q, of the Commission’s rules, and seek comment regarding bidding credits for small businesses.
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Frequency Bands |
| Band | Use | Service | Table |
| 14 - 14.5 GHz | - | Aeronautical Mobile (R) | N |
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Iridium
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Iridium is a mobile-satellite service (MSS) system that was first licensed by the FCC in 1995, and began commercial service in 1998.
Iridium utilizes an FDMA/TDMA Time Division Duplex (TDD) access technology, so that the same frequency band is used for both the user uplink and downlink transmissions, on a time-shared basis. It shares a portion of its spectrum (1617.775-1618.725 MHz) with Globalstar, which has mobile uplinks to its own MSS system in the 1610-1618.725 MHz band.
Each Iridium user uplink/downlink channel has a bandwidth of 31.5 kHz and is separated in frequency by 41.67 kHz to allow for Doppler shift. A single Iridium TDMA frame is 90 ms long, which begins with 22.48 ms guard time, followed by four user uplink and four user donwlink time slots (8.28 ms burst time each, separated by small guard times).
A good discussion of the Iridium system architecture, constellation design, and multi-access scheme can be found in chapter 2 of the thesis by Abdul Jabbar (link below).
In February 2013, Iridium was granted authority by the FCC to provide aeronautical mobile-satellite (route) service (AMS(R)S) in the 1618.725-1626.5 MHz portion of its spectrum, limited to oceanic, polar, and remote regions. According to the FCC, "for purposes of this authorization, we consider oceanic regions to be those beyond 12 nautical miles from the baselines of the coastal states." Authorization for remote areas of other territories is contingent upon completing the agreement-seeking process under 5.367 of the ITU Radio Regulations.
At the end of 2012, Iridium reported approximately 368,000 subscribers. The company plans to launch a new generation of satellites, Iridium Next, beginning in 2015.
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Frequency Bands |
| Band | Use | Service | Table |
| 1617.775 - 1626.5 MHz | Iridium (user terminal uplinks and downlinks) | Mobile-satellite | N |
| 1618.725 - 1626.5 MHz | Iridium AMS(R)S | Aeronautical Mobile (R) | N |
| 19.1 - 19.6 GHz | Iridium satellite gateway downlinks | Fixed-satellite (space-to-Earth) | N |
| 22.55 - 23.55 GHz | Iridium inter-satellite links | Inter-satellite | N |
| 29.1 - 29.3 GHz | Iridium gateway uplinks | Fixed-satellite (Earth-to-space) | N |
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