HiSeasNet Satellite Basics - unols.org Satellite Basics Steve Foley Scripps Institution of...

HiSeasNet Satellite Basics

Steve Foley

Scripps Institution of Oceanography

November 5th, 2012LDEO

1

Wednesday, February 13, 2013

Outline Key satellite issues

Footprints, power, orbits, antennas, bands, polarization, spectrum, etc.

Different types of satellite networks/services Economics

Earth stations Data over satellites

Operators/Providers, modems, EbNo, routers, etc.

The future of satellite communications

2








3


Network Overview

4


Satellite structure/position Satellites currently orbiting the earth represent a wide variety of

sizes, shapes and capabilities, each designed for specific purposes.

Based on function and purpose, they can have Low, Medium, or Geostationary orbits

The designed purpose dictates what type of orbit they are placed in, frequency band of operation, types of transmissions, power levels emitted and where their signal(s) are directed.

The different sizes and shapes vary widely, but all satellites have the same basic elements.

Stabilization, telemetry equipment, and boosters are all used to keep the satellite oriented properly in its specific orbital position.

Solar panels and batteries are used to power the transmit and receive RF equipment and telemetry systems which are used to track & control the satellites' position. 5


Types of Satellite Orbits LEO (Low Earth Orbit)

500 to 1000 miles above the earth

MEO (Medium Earth Orbits) 8000 miles above the earth

GEO (Geostationary Earth Orbit) 22,753.2 miles above the earth

Inclined orbits, Molniya, etc

6

GEO

MEOLEO

J-Track 3D Satellite Tracking


http://science.nasa.gov/realtime/jtrack/3d/JTrack3D.html/

http://science.nasa.gov/realtime/jtrack/3d/JTrack3D.html/

Geosynchronous Orbit Clarke Orbit

Named after, Arthur C. Clarke, who first envisioned its potential for global communications usage in 1945.

Also called a geostationary orbit

If a satellite is positioned about 22,236 miles above the equator, its rotational speed will match that of the earth and, therefore, appear to remain in a fixed position when viewed from the earth’s surface. These satellites are referred to as "Geo-Synchronous" or "Geo-Stationary".

Many serve a wide variety of communications services including telephone, data, radio and television. These are the satellites that SeaTel antenna systems are most commonly used with.

7


Geosync Orbit They are all in orbit over the Equator (0 degrees Latitude) and so

are usually referred to by their "longitudinal" position as often as by their name.

Starting from 0 degrees longitude increasing in degrees East or West to 180. At these two points a satellite could be called 0.0 degrees East or West, or 180 degrees East or West respectively.

Satellites move around a little due to solar wind, sun/moon gravity tweaks, etc. Sats have a fixed fuel source to keep them on station

8


Satellites as relay Communication satellites are relay links (repeater) in

space. They have very sophisticated antennas & RF equipment They have highly focused antenna patterns (footprints) They can utilize 350 Watts per transponder, more every

generation

They utilize either linear or circular polarization which requires the correctly polarized feed on the ship’s antenna

The ship must be in a strong enough area of the satellite’s footprint for antenna system to operate.

Regardless of the type of signal, they are all relay devices, located in space to re-broadcast their signals to a much larger area than would be possible by local area (TV Station) transmissions.

9


Satellite Orbital Spacing In the simplest form 3 satellites would be required to

provide global coverage, with each satellite illuminating about 42% of the earth’s surface.

As time has passed, the number of satellites in Geosynchronous orbit has increased to the present population of more than 230 satellites.

The satellite positions are regulated by multi-national organizations which use illumination area, frequency allocation and polarity usage to plan satellite positioning (for each type of services) in such a way as to provide for the greatest number of satellites possible without interfering with each other.

Good planning and co-operation (among satellite operators and users alike) are required to achieve the goal of locating the satellites 2 degrees apart from each other in longitudinal position.

10


11

Boeing 67Others 236*

* Includes Eutelsat-leased S/C: Sinosat-3 (Eutelsat 3A) and AM 22 (Sesat 2)

30 Jun 2012 / 228265-001.aiInt

elsat 9

02

62.0°E64

.0°E

Intels

at 906

Inmars

at III

F-1

64.5°

E

Intels

at-17

68.5°

E

Intels

at-7,

-10

Eutel

sat 7

0A

70.5°

E

72.0°

E

Intels

at 70

6, 70

9, 22

; Lea

sat F

-5 (I)

52.5°E

Yahsat 1A

50.0°E

Galaxy 26, Intelsat-26

51.0°E

Sirius 3

51.5°E

Apstar 1A (I)

90˚E

Eutelsat 16A, B, C (I)16.0°E

17.0°E

Amos 5

Intelsat 10-02; Thor 5, 6 1.0°W

Eutelsat 5 WEST A5.0°W

18.0°W

Intelsat 901

20.0°W

NSS-5, -7

22.0°W

SES-4

34.5°W

Intelsat 903

43.0°W

Intelsat-11

37.5°W

NSS-10, Telstar 11N

40.5°W

NSS-806

45.0°W

Intelsat-14

50.0°W

Intelsat-1R

47.0°W

NSS-703

29.5°W

Intelsat 801

53.0°W

Intelsat 707

24.5°W

Intelsat 905

27.5°W

Intelsat 907

Telecom 2D (I), Eutelsat 8 WEST A8.0°W

Eutelsat 12 WEST A

12.5°W

Nilesat 101, 102, 201; Eutelsat 7 WEST A7.0°W

178.0°E Inmarsat III F-3, Intelsat 602 (I)

154.0°E

JCSat 2A

31.5°W

Intelsat-25

135°E

180°

135˚W

90˚W

45˚W

45˚E

91.5°EMEASAT 3, 3A

92.0°EChinasat-9

93.5°EInsat 3A, 4B

95.0°ENSS-6

98.5°EThuraya 3 (I)

87.5°

E

Chin

asta

r-1

85.0°

E

Inte

lsat-1

5/JCS

at-8

5; H

orizo

ns-2

88.0°

EST

-1, -

2

180.0°E Intelsat-18

172.0°EGE-23

162.0°E

Superbird B2

164.0°E

Optus B3

160.0°E

Optus D1

156.0°E

Optus C1, D3

158.0°E

Superbird A3 (I)

157.0°E

Intelsat 701

152.0°E

Optus D2

177.0°WNSS-9

139.0°W

AMC-8

142.0°W

Inmarsat II F-2 (I)

137.0°W

AMC-7

135.0°W

AMC-10

131.0°W

AMC-11

133.0°W

Galaxy 15

125.0°

W

Galaxy 14, AMC-21

127.0°W

Galaxy 13/Horizons-1

129.0°W

Galaxy 12, CIEL-2

111.0°

WAn

ik F2

, Wild

Blue 1

, Terr

estar

-1

110.0

°WEc

hosta

r X, X

I; DIRE

CTV-5

, -1R

105.5°E

Asiasat 3S, 7

105.0°E

Asiastar 1100.5°E

Asiasat 5

110.5°E

113.0°E

Palapa D, Koreasat 5

132.0°E

JCSat 5A; Vinasat 1, 2

134.0°E

Apstar 6

136.0°E

N-Star C

107.5

°W

Anik

F1, 1

R

106.5

°W

MSAT

-1

105.0

°W

AMC-

15, -1

8

103.5

°W

MSAT

-210

1.0°W

99.0°

W G

alaxy

16, S

pace

way 2

98.0°

W In

mars

at IV

F3

95.0°

WGa

laxy 3

C, S

pace

way 3

96.0°

WSi

rius 5

93.0°

WGa

laxy 2

5, DB

SD-G

1

97.0°

WGa

laxy 1

9

87.0°WSES-2

89.0°WGalaxy 28

84.0°W

Brasilsat B4

83.0°W

AMC-9Nimiq 4

82.0°W81.0°W

25.0°E

Inmarsat IV F2

16.0°W

Inmarsat III F-2

Eutelsat 7A7.0°E

Eutelsat Hot Bird 13A, B, C13.0°E

Intelsat 603 (I)11.5°E

23.5°E

Astra 1D (I), 3A, 3B; THOR 2A (I)

57.0°E

NSS-12

55.5°E

Galaxy 11

53.0°E

SESAT 2 [Express AM-22]

56.0°E

MOST-1 [BONUM]

Intelsat 9

04

60.0°E

66.0°

E

103.0

°W

AMC-

1; Sp

acew

ay 1;

DIRE

CTV 1

0,12;

SES-3

24.5°E

Inmarsat III F-5

25.5°E

Eutelsat 25A

116.0°E

ABS-7, Koreasat 6

115.5°E

Chinasat 6B

118.0°E

Telkom 2

174.0°W

TDRS-5

72.0°W

AMC-6

73.0°W

Nimiq 5

70.0°W

STAR ONE C2

128.0°E

JCSat 3A, 12 (IOS)

124.0°E

JCSat 4A, 13

123.0°E

Garuda 1

169.0°EIntelsat-5

Apstar 5/Telstar 18

138.0°E39.0°E

Hellas-Sat 2

45.0°E

Intelsat-12, Galaxy 27

43.5°E

Thuraya 2 (I)

47.5°E

Intelsat 702; Yahsat 1B

48.0°E

Eutelsat 48A, B

46.0°E

Africasat 1 [Measat 1]

75.0°W113.0

°W

SatM

ex 6

115.0°

W

XM Blue

s, Roc

k, Roll

; Soli

darid

ad 2

(I); Vi

aSat-

1

78.5°

E

Thaic

om 5

80.0°

E

Esiaf

i 1 (I)

[Com

star D

4]

117.0°

W

SatMex

5

DIRE

CTV-

4S, -8

, -9S,

-11;

SES-1

101.5

°W

SkyT

erra

1

150.0°E

JCSat 1B

150.5°E

Palapa C2 (I)

19.2°E

Astra 1H, 1KR, 1L, 1M, 2C

Amos 2, 34.0°W

ABS-33.0°W

Thor 34.5°W

144.0°E

Superbird C2, MBSAT 1

142.0°E143.5°E

Inmarsat IV F1

21.0°E

Afristar

20.0°E

Arabsat 5C

21.5°E

Eutelsat 21A

30.5°E

Arabsat 5A

31.5°E

Astra 1G

31.0°E

Intelsat 24 (I) 26.0°E

BADR-4, -5, -6

78.0°W

VENESAT-1

77.0°W

QuetzS

at-1; Echostar I, VI, V

III

123.0°

W121

.0°W

Echosta

r IX/Gala

xy 23

Thaicom 4

119.5°E122.0°E

Asiasat 4

119.0°

WEchosta

r VII, X

IV; DIRECTV

-7S; A

nik F3

75.0°

E

ABS-

1, -1A

[Kor

easa

t 2] (I

)

55.5°W

Intelsat 805

54.0°W

Inmarsat III F-4

65.0°W

STAR ONE C1 67.0°W

AMC-3, -4

68.0°W

Brasilsat B2 (I)

58.0°W

Intelsat-9, -16

Apsta

r 2R,

7

76.5°

E

61.0°W

Amazonas-1, -2

63.0°W

Estrela do Sul 2/Telstar 14R

91.0°

W

36.0°E

Eutelsat 36A, B

34.5°E

Arabsat 2B

33.5°E

Hylas-1

Intelsat-8, -19

166.0°E

28.2°E

Astra 1N, 2A, 2B, 2D

29.0°E

Xtar-EUR

28.5°E

Eutelsat 28A

108.0°ECakrawarta 1, Telkom 1, NSS-11, SES-7

15.0°W

Telstar 12

110.0°EBSAT-2C, -3A, -3B -3C; N-SAT-110

Note: (I) Inclined orbitBased on best public information available at the time.

Sirius 163˚ Inclination between 140˚W and 60˚W

Sirius 2Sirius 3

MEOICO-A1

DRIFTING:

Amos 5i [Asiasat 2]

LMI AP 2 (Gorizont 30)

30.0°W

Hispasat 1C, 1D, 1E; XTAR-LANT [Spainsat]

74.0°

E

Insat

3C, 4

CR

Brasilsat B3A (I)

61.5°W

Echostar III, XII, XV

Rascom 1R; Eutelsat 3A, CAstra 1C (I)0˚

Sinosat-1/Intelsat APR-2

42.0°E

Turksat-2A (I), -3A

Eutelsat 10A10.0°E

Astra 4A, 1E; AMC-2

Galaxy

18

Apstar 1 (I)

Gala

xy 17

; Nim

iq 1,

2, 6

Eutelsat 9A, KA-SAT 9A5.0°E

3.0°EEutelsat 4A 4.0°E

2.0°E

9.0°E

33.0°E

Eutelsat 33A, Intelsat New Dawn

83.0°

E

Insat

4A

Commercial Communications SatellitesGeosynchronous Orbit

85.0°WAMC-16; XM Rhythm

85.5°WXM-5

55.0°E

Insat 3E, 4G; Astra 1F

AMC-5


Satellite Design Solar panels for power

Antennas for communications Configurations, spectrum, amplifiers, fuel, footprints, often fixed at launch

Intelsat 18 (similar to IS-23 for our AOR) 180deg W, POR coverage Ku-band and C-band transponders

12


Satellite RF Equipment Each satellite has redundant receive and transmit

equipment capable of operating in its assigned frequency band(s).

Satellites can employ multiple antennas, so they can have switching equipment that will direct selected transponder outputs to a particular antenna.

Multiple antennas provide multiple or “spot” beam footprints

Better control of bandwidth used by each transponder = more transponder channels within each frequency band.

Some bands (like Ku-band) have even been split into multiple sub-bands because they are now being used so efficiently.

Modern satellites have 32+ transponders which are capable of transmitting C and Ku Band simultaneously at high power levels (150-250 Watts). 13


The Satellite Antenna Sophisticated satellite antenna designs provide highly

focused illumination patterns that are called footprints.

Some of these illumination patterns are shaped to fit the geographic area of coverage.

Focusing and shaping the beam concentrates the transmitted energy into the footprint of the desired area of coverage without wasting any of it elsewhere.

This increases the overall receive level (Effective Isotropic Radiated Power -EIRP) throughout the footprint pattern, allowing smaller (lower gain) dishes to be used in receive only systems.

Some of these antennas provide very wide coverage allowing them to receive from, or transmit to, an area equal to about 40% of the earth’s surface (global beams)…at the cost of power and thus antenna size

14


Uplink and Downlink The satellite itself is a relay device, receiving and re-transmitting

signals.

Transmitted signals originate from an Earth Station, or in special cases, another satellite.

These uplink signals are received at the satellite on one frequency, routed to the on-board conversion & transmission equipment, and transmitted as the downlink signal at a different frequency.

Transmissions from earth use higher frequencies while transmissions from satellites use lower frequencies. First satellites had limited power and lower frequencies have less attenuation (loss).

The received and transmitted signals may use the same antenna and be using the same area of coverage (footprint). This UP-DOWN link is called a “single hop”. Some signals require multiple satellites and are know as “double hops”

An "Earth Station", can be fixed or mobile. A fixed station is one which does not move (stationary position) and a mobile station is one which is capable of changing position (ie.. a news van, or a HiSeasNet ship).

15


Satellite Carriers The data from a satellite signal is wrapped up in these little bumps in

the spectrum

Taller bumps are easier to lock onto, have for fade margin

Wider bumps have more data

When you increase a bump’s width without changing power, the height comes down

Best seen with a spectrum analyzer

16


Satellite Frequency Bands The next slide gives Uplink and Downlink

frequencies of the Satellite Bands. A wide band of frequencies is shown in the next

slide. It is important to note that frequencies used by other

electronic systems may interfere with the satellite system. CB, TV UHF & VHF and especially navigational radars are examples of possible interference sources.

Several sub-sands maybe in use within what is commonly called C & Ku bands.

Certain sub-band usage may be restricted to a given geographic area in an effort to extend the maximum number of satellite signals in that area while minimizing interference.

17


Standard Satellite Frequency Bands

Ku-band has many sub bands that are used differently in different places

Band Uplink Freq (GHz)

Downlink Freq (GHz)

C-Band 5.9-6.4 3.7-4.2

Ku-Band 14.0-14.5 11.7-12.2

Ka-Band 27.5-31.0 18.3-18.819.7-20.2

18


Rain Fade Attenuation

Rain Fade is the common term for Rain Attenuation. This attenuation (or signal strength loss) is caused by the absorption of the satellite signals by heavy rain.

Below is a chart that shows typical attenuation based on rain rate with the subject antenna set to a 30 degree elevation angle

19


Frequency Band Pro/Con C-Band Frequencies

Advantages: Wide footprint coverage Minor rain fade issues

Disadvantages: Requires larger

antennas Requires larger SSPA Affected by terrestrial

interference (TI) = more rules/regulation

More work to obtain a TX License

Ku-Band Frequencies Advantages

Requires smaller antennas for a focused beam

Requires smaller SSPA Less interference

problems (farther from other bands) = less regulation = easier to obtain a TX license

Disadvantages Big rain fade issues Smaller footprint, not

global 20


Satellite Polarization Frequency polarization is a technique designed to

increase the capacity of the satellite transmission frequency.

In linear cross polarization schemes, half of a satellite’s transponders transmit their signals to earth in vertically polarized mode; the other half of the satellite’s transponders transmit their signals in horizontally polarized mode.

Although the two sets of frequencies overlap, they are 90 degree out of phase, and should not interfere with each other. Sometimes they do interfere, so we have to adjust

antenna feed to isolate “Cross-Pol interference” For both satellites and earth stations the normal

configuration is to transmit in one polarization and receive in the opposite polarization.

21


Satellite Polarization - Linear and Circular

Linear polarization Horizontal or vertical Cross-pol vs co-pol (Tx/

Rx in same or different polarity)

Circular polarization Right or left

Antenna feed must match satellite transponder

Must isolate signal to one polarity to avoid interference with other polarity

22


Satellite Frequencies and Transponders

A Transponder contains a block of frequencies on a satellite. Typical bandwidth is 40MHz per transponder (36MHz usable - 2 MHz of guard band on each side). Some Ku-Band transponder are 54MHz & 72MHz.

Rx (MHz) 11720 11760 11800 11840 11880 11920 11960 12000 12040 12080 12120 12160

Tran. 1 3 5 7 9 11 13 15 17 19 21 23

V

Tx (MHz) 14020 14060 14100 14140 14180 14220 14260 14300 14340 14380 14420 14460

Tran. 1 3 5 7 9 11 13 15 17 19 21 23

H

Rx (MHz) 11740 11780 11820 11860 11900 11940 11980 12020 12060 12100 12140 12180

Tran. 2 4 6 8 10 12 14 16 18 20 22 24

H

Tx (MHz) 14040 14080 14120 14160 14200 14240 14280 14320 14360 14400 14440 14480

Tran. 2 4 6 8 10 12 14 16 18 20 22 24

V

Typical Ku-Band Satellite Transponder Plan 23


Geo-sync Satellite Summary Satellites are relay devices, re-broadcasting signals to a large area on earth (footprint)

They operate in a variety of frequency bands and can have multiple antennas which allow the transmitted energy to be aimed and focused very accurately in multiple beams.

The power of each beam dissipates as the area of coverage increases. Contour maps are published by the satellite owners that show the beams’ signal strength lessens as the footprint size increases.

They are in Geo-Synchronous orbit over the Equator, therefore, appear to remain in a fixed position when viewed from the earth’s surface.

Because they are all at 0 degrees Latitude (Equator) they are commonly referred to by their Longitudinal position.

It is common for a satellite to alternate transponder polarities, (Horizontal & Vertical, or Right & Left hand Circular) to prevent interference of one channel to another, and for adjacent satellites to reverse their transponder polarities.

Other Electronic Systems may interfere with your Satellite System (CB, TV UHF & VHF and especially Navigational RADARS). Varies with frequency, power, antenna.

Satellite signals are typically focused, and aimed, at the populated land mass areas of the globe.

24


Satellite Beam (Footprint) The beam pattern of the signal transmitted by the satellite

is a function of the antenna being used.

The pattern is based on the antennas' radiated field pattern when it was tested prior to launch.

A given amount of power spread over a wide area, such as a Global beam covering 42% of the earth’s surface, makes the signal level very weak at all locations within that area.

A Hemi-beam only covers about 20% of the earth’s surface and would have signal levels at least 3dB higher (half the area equals twice the effective power) throughout its coverage.

Area beams cover about 10%, doubling the power again (another 3dB higher) over a Global beam and Spot beams may be as little as 2% (another 6 dB higher).

25


Example Footprint

26


Satellite Footprint Basics Transmit power, beam-width, frequency band, and polarization mode

are all important factors of the signal transmitted by the satellite.

The ship’s location within the footprint, the overall gain of the system, blockages and atmospheric conditions are the primary factors in the system’s ability to receive the signals from a desired satellite.

Transmit Power The transmit power of some satellites is as little as 8 Watts per transponder.

Some newer satellites are capable of 350 Watt transmission. The higher the transmitted power level, the stronger the receive signal will be at

any point within the footprint.

Transmitted Beam Width A fixed amount of power is being transmitted into the footprint area. The larger

the area is (wider beam width), the lower the received signal level will be at any given point within that footprint. The smaller (narrower beam width) the footprint area is, the higher the received signal level will be at any point within it.

Frequency Band and Polarization Type The frequency of the transmission is not as important as the power level or

beam-width, but lower frequencies offer a slightly better atmospheric penetration (less attenuation). Circular polarization also offers better penetration of fog and rain (over linear transmissions).

27


Example Footprint

28


Satellite Footprint Basics The signal level of a given footprint is always strongest in

the center, decaying (basically in concentric rings) out to the fringes, not necessarily uniform rings

Even when the ship is in a footprint, the antenna may not be receiving enough signal level for the DAC or the modem to be able to process it properly. Tx power may also be a problem.

Footprint charts are usually mathematically generated patterns, based on the antennas' performance BEFORE launch, overlaid on pictorial locations of earth. A given satellite can have multiple footprints, with some transponder signals in one but NOT in others.

In any given satellite footprint, atmospherics change through the day will cause the transponder signal levels to change accordingly.

29


Example Footprint

30


Satmex 5 - Beam 1 Ku-Band Satellite provides Ku-Band service for

HiSeasNet ships and other users

Running out of fuel awaiting SatMex8 replacement

Operated by SatMex – Mexican company operating 3 satellites geared towards servicing Mexico and N. America

Beam 1 covers Continental U.S. (including Pacific & Atlantic coasts), Mexico, and Gulf of Mexico

Located at longitude of 116.8 degrees West (or 243.2 East)

Shows EIRP Footprint contours (in dBW)

Note: Decreasing EIRP values from beam center to

edge

Hot spots

Sudden drop at the edge31


GE-23 Satellite

Constant ownership change -- Now called “Eutelsat 172A” Unusual Ku-band footprint over North Pacific, other wide-ish footprints, too Wider beam is weaker and requires minimum 1.5m antenna for efficiency No earth station capabilities right now (Look angle from San Diego is 6

deg!) Strange co-pol polarization, needs some ship modifications Low look angle in US port and coastal waters

32


Galaxy-18 Satellite

Hot spots…Why?

Strong or weak satellite?

Main purpose? What could HSN use it for? What ships? 33


Satellite Station Keeping Even new satellites have a little wiggle in

their orbits a little bit

They need some fuel to keep themselves in a known/fixed box so that fixed antennas can keep generally peaked up

Satellites are launched with a fixed fuel supply

If replacement satellite gets delayed, satellites may save fuel by increasing the size of the box and allowing signals to fade more

34


Solar Outages During the year, the sun and satellite

move a little bit with respect to each other

In the Spring and Fall, the sun passes behind GEO satellites enough to cause 5-10 min outages for a few weeks

Depending on the ship position and look angles, there are 2 opportunities for each day to have outages (Ship and earth station)

35








36


SCPC VSAT (Very Small Aperture

Terminal...using a focused dish) SCPC = Single Channel Per Carrier One direction per carrier, fixed data path Leased spectrum directly, paid by the

month, do what you can with it Power limits as to how many carriers you

can have Simple equipment on ship and at earth

station

37


iDirect VSAT based

Time Division Multiple Access (TDMA) technology Lease a big block of spectrum (many MHz)

Time slice who gets to talk when More time slices, more resolution Give away extra slices if you have them

Needs expensive earth station gear, special modems

Doesn’t address wider coverage, just deeper coverage

38


FBB/BGAN L-band technology, less spectrum

available, not VSAT

Small antenna

Voice and data terminal

Pay-by-the-byte/minute plans

Higher latency (1200-1400ms RTT)

Some flexibility in data path

39


Iridium Truly global coverage, pole-to-pole

Voice service, too

Smaller terminals (0.5m, 25lb), lower data rates (136kbps)

Not all satellites talk back to earth directly Longer delay, possibly frequent handoffs between

satellites

Costly depending on plan

Next-gen launches are 2015-2017, with data rates of 1.5Mbit (L-band) to 8Mbit (Ka-band)

40








41


Power Equivalent Bandwidth With each fraction of a transponder’s

spectrum comes a fraction of its power Ex: Buy 1MHz on a 36MHz xponder, get 1/36th

the power on that transponder

Bigger antenna = bigger footprint = less power required

A ship can sometimes use a smaller antenna, but needs more power Ship amp must have the power, and must have

leased enough bandwidth to be allowed to use it

42


Satellite operator’s view I have only so much capacity in the sky

How do I make the best use of that capacity? Long term lease for a small chunk? A big

chunk? Occasional use? Short term, but more

costly... A big block that can get re-sold as a time

division block?

43


iDirect systems Aggregated service for many ships

Can be over-subscribed or under-subscribed...even for the area

Pay for either a committed information rate (CIR) or a SCPC-like setup

44


Inmarsat services Option 1: Open up a big, efficient pipe

and pay by the minute of use Good for bulk data dump, but need to be

quick about it

Option 2: Swap packets in/out all the time, but pay by the byte

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HSN Bandwidth Economics HSN leases spectrum by the week or month on 1

year or less leases

Longer leases = cheaper monthly rate

Short term leases (weeks or months) Usually 30% more for bandwidth Have 1-time setup costs applied ($500-2000)

Wherever we can, no middle-man or service provider

Doesn’t get much more bare-bones than HSN Minimal operations staff Equipment maintenance and spares pool Direct SCPC leases (~75+% of the budget)

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HSN Additional Satellites Sometimes we get bandwidth on

different satellites (G-18, IS-906, etc.)

Requires earth station services (additional monthly cost)

Requires additional time and engineering for ship and shore

Multiple ships get even trickier, but are possible

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Earth Stations Only need them if you want your data to go

somewhere on earth.

Where signals come out of the sky and hit the Internet and vice versa

A good station needs: A view of the satellite we are talking on Terrestrial bandwidth/access Big enough antenna and amplifier to sustain carrier(s) Decent enough weather for the band Redundancy in power, data, etc Responsive staff

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Bigger antennas to work with smaller remote stations

No tracking

Good access to data network

Rack of modems and routers 50


HSN Earth Station Tour

Modems

Routers

Remote control

Network 51

Antennas

RF gear

A/C and power


Intelsat Napa

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Operators vs Providers Just like in the terrestrial world, there are the

infrastructure folks and the service folks

Satellite operators provide a chunk of spectrum/power and let you do what you want with it. SatMex, Intelsat, Inmarsat, SES WorldSkies, etc. Voice? Video stream? SCPC data? TDMA network?

Service providers do all that Internet magic Downlink to earth, routing, VPNs, email, etc.

Sometimes the operators also provide services

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Hardware Beyond the RF gear that pushes energy

out the dish, what gear you have below decks depends on what you want to do.

Satellite Modems do what other modems do: Modulation/Demodulation

If doing IP, need a router (may be integrated with modem)

After a router, then what?

The world is your oyster...55


Quality Signals get rough around the edges, obstructions,

noisy gear, rain fade, etc.

In order to push good data across, there needs to be enough signal quality and extra information to handle errors in transmission/reception

EbNo is our measurement: Energy per bit over Noise

Our modems are good, but we still need an EbNo of about 3.5 or better to push data smoothly

We can trade EbNo for data rate sometimes (“margin”) Stronger signal (more tolerance to problems) with a slower

data path. 1/2 the data rate = 3 dB of EbNo

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Typical ShipNetwork Setup

Fancy tweaks include: Fail over between

FBB, 3G, HSN Crypto Acceleration (hidden

across the satellite) DHCP for the DMZ

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A time of transition… L-band technologies and spectrum may be

bottoming out on its price as spectrum is limited

Ka-band has some wide open spectrum and high capacity, but rain fade and footprint issues

Ku-band and C-band are still operating mainstays of VSAT comms

Maritime use is tricky with Stabilized antennas Global range Not near land masses Weather issues

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Known Ka-band Systems O3b Networks has an MEO system going up

later this year Up to 1Gbps speeds, 150ms latency, 1.2-2.2m

antennas Spot beams, +45/-45deg latitudes

Inmarsat GX launching soon, complete in 2015 Targeting 50/5Mbps speeds, 60cm Ka- antennas

Intelsat EpicNG - wide/spot/coding combo of C/Ku/Ka bands Mostly marketing-speak right now, no details Available...eventually/gradually

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Ka-Band Good More hardware is becoming available for Ka-

band, cost is falling New technology going up on satellites that is

100x more capacity than Ku-band now (Gigabit beams)

Much more capacity in the sky should bring prices down

Ocean areas are sometimes being lit up for aircraft

SeaTel is working on smaller stabilized antennas for Ka-band, but still 1m-ish

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Ka-Band Bad Weather fade issues are even worse

than Ku-band

Footprints are often more focused that Ku-band

Services aren’t up in the sky quite yet Earliest systems up late this year, early

next year Complete networks in the next few years

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But wait…there’s more The industry is trending towards service

providers for this greater capacity

Will satellite access be like cell phone access? Cheaper, but less control over the network?

Time will tell what direction things go, likely some hybrid multi-band solutions for a while C-band in open ocean, Ku- or Ka- while near

shore? Need large, multi-band antenna to be efficient at all.

Ka- or Ku- in shore, but slow L-band while open ocean? Smaller antennas, but speed limits at sea.

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Questions/Issues? Any of that make sense?

What do you want to hear about tomorrow?

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HiSeasNet Satellite Basics - unols.org Satellite Basics Steve Foley Scripps Institution of...

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