Download - LINK ANALYSIS OF HIGH THROUGHPUT SPACECRAFT … · National Aeronautics and Space Administration Waveform: QPSK, FEC Rate: 7/8, Frequency = 25.25 to 27.5 GHz Waveform: QPSK, FEC Rate:

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Waveform: QPSK, FEC Rate: 7/8, Frequency = 25.25 to 27.5 GHz Waveform: QPSK, FEC Rate: 7/8, Frequency = 22.55 to 23.55 GHz

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s)

LEO User EIRP (dBW)

G/T = 17 dB/K G/T = 23 dB/K (Program Track) G/T = 26.5 dB/K (Auto Track) G/T = 32 dB/K

LINK ANALYSIS OF HIGH THROUGHPUT SPACECRAFT COMMUNICATION SYSTEMSFOR FUTURE SCIENCE MISSIONS

RAINEE N. SIMONS, NASA GLENN RESEARCH CENTER, 21000 BROOKPARK ROAD, CLEVELAND, OHIO 44135

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LEO EIRP (dBW)

Data Rate (Mbps) Bandwidth (MHz)

LEO User Tx Ant Dia: 0.5 m, Tx Frequency: 26 GHz, User Ant Dia: 0.5 m, G/T: 14.8 dB/K, 99% Availability at WSC, Elevation Angles: ≈30°

606 MHz

1.2 Gbps

42.4 dBW

8PSK Rate 9/10

DATA RATE AND BANDWIDTH VS. LEO SPACECRAFT EIRP(LEO USER TERMINAL TO GROUND (WSC))

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Data Rate Bandwidth


606 MHz

1.2 Gbps

45.2 dBW

8PSK Rate 9/10


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LEO EIRP (dBW)

Data Rate Bandwidth


1136 MHz

1.2 Gbps

40.5 dBW

QPSK Rate 7/8


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LEO EIRP (dBW)

Data Rate Bandwidth


1136 MHz 1.2 Gbps

43.3 dBW

QPSK Rate 7/8


• In the next ten years NASA plans to launch several spacecraft into Low Earth Orbit (LEO) for remote sensing of the Earth with instruments that will accumulate several hundred gigabits of data per orbit• The ability to handle such a large volume of science data per orbit far exceeds the capabilities of NASA’s current space and ground assets• The paper proposes two solutions: first, a high data rate link between the LEO spacecraft and ground via relay satellite in geostationary orbit (GEO). Second, a high data rate direct to ground link from LEO

I. INTRODUCTION SPACE-TO-SPACE LINKS AND SPACE-TO-GROUND LINKSVIA RELAY SATELLITE

RELAY SATELLITE EIRP VS. LEO SPACECRAFT G/T(GEO-TO-LEO Ka-BAND SINGLE ACCESS FORWARD LINK)

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EO R

elay

EIR

P (d

BW

) LEO User G/T (dB/K)

Data Rate = 0.1 Mbps Data Rate = 1 Mbps

Data Rate = 10 Mbps Data Rate = 25 Mbps

Program Track EIRP = 59.5 dBW Auto Track EIRP = 63 dBW

ACHIEVABLE DATA RATE VS. LEO SPACECRAFT G/T(GEO-TO-LEO Ka-BAND SINGLE ACCESS FORWARD LINK)

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LEO User G/T (dB/K)

Waveform: QPSK, FEC Rate: 7/8, Frequency = 22.55 to 23.55 GHz

Auto Track EIRP = 63 dBW Program Track EIRP = 59.5 dBW

RELAY SATELLITE G/T VS. LEO SPACECRAFT EIRP(LEO-TO-GEO Ka-BAND SINGLE ACCESS RETURN LINK)

Waveform: QPSK, FEC Rate: 7/8, Frequency: 25.25 to 27.5 GHz

25 Mbps 100 Mbps 600 Mbps 1.2 Gbps

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Rel

ay G

/T (d

B/K

)

LEO User EIRP (dBW)

Program Track 23 dB/K

Auto Track 26.5 dB/K

ACHIEVABLE DATA RATES VS. LEO SPACECRAFT EIRP(LEO-TO- GEO Ka-BAND SINGLE ACCESS RETURN LINK)

DATA RATE AND BANDWIDTH VS. RELAY SATELLITE EIRP(60 GHZ, LDPC 9/10)

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8PSK

16APSK

32APSK

The relay satellite to ground station down link operates at K-band frequencies (20.2 to 21.2 GHz)

IV. K-BAND GEO-TO-GROUND LINK

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GEO

EIR

P (d

BW

)

Ground Receiver G/T (dB/K)

GEO EIRP (dBW)

TWT Pout: 46.1 W ≈ 50 W TWT OBO: 5.3 dB TWT Psat: 156.2 W ≈ 160 W

RELAY SATELLITE EIRP VS. GROUND RECEIVER G/T

VI. CONCLUSIONS

Results from computer simulationscarried out for high-data-rate LEO-to-GEO,

GEO-to-GEO, GEO-to-ground, andLEO-to-ground links to down load largevolume of science data are presented

PS–01620–0615

2015 IEEE International Symposiumon Antennas and Propagation and

North American Radio Science Meeting19–25 July 2015 • Vancover, BC, Canada

The relay satellites are located in GEO. The LEO-to-GEO link is designated as the return link (RL) to the relay satellite and operates at Ka-band (25.25 to 27.0 GHz) frequencies. The GEO-to-LEO forward link (FL) operates at K-band (22.55 to 23.55 GHz) frequencies.

II. KA-BAND SPACE-TO-SPACE LEO-TO-GEO LINK

LEO-TO-GEO RELAY SATELLITE LINK

RL

FL LEO GEO

RELAY SATELLITE EIRP VS. ANTENNA DIAMETER

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EIR

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BW

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Antenna Diameter (m)

EIRP (dBW)

State-of-the-Art V-Band (60 GHz) Space TWTA Pout ≈ 70 Watts

The forward (FL) and return (RL) links operate atV-band frequencies (59 to 64 GHz), but with oppositesense of polarization to minimize interference

III. V-BAND GEO-TO-GEO INTERSATELLITE LINKS

FL

RL

RL FL

RL

FL

GEO

GEO-TO-GEO INTERSATELLITE LINKS

62.5-64 GHz f0 = 63.25 GHz 3 Gbps Rx (LHCP) 8-PSK waveform Ant Dia = 1.132 m

Demod/Remod

LNA

K-Band HPA

20.2-21.2 GHz f0 = 20.7 GHz 3 Gbps Tx (RHCP) 32-APSK waveform

Ant Dia = 2.4 m (Modeling indicates a 1 m aperture on the relay and 9m aperture on ground is adequate for K-Band)

25.25-27.50 GHz f0 = 26 GHz 3 Gbps Rx (LHCP) 8-PSK waveform Ant Dia = 4.9 m

59-60.5 GHz f0 = 59.75 GHz 3 Gbps Tx (RHCP) 8-PSK waveform Ant Dia = 1.132 m

LNA V-Band

Upconverter

LO 33.75 GHz

59-60.5 GHz

V-Band HPA

Diplexer

LO 42.55 GHz

V-Band Downconverter

V-Band IF Amp

Pre Compensation Amp

Ku-Band

SA

SPE

XL

SPE SGL

Ka-Band Downconverter

Ka-band Switch

LO 5.3 GHz K-Band Switch

TX AND RX CHAIN ONBOARD THE RELAY SATELLITE FORSPACE-TO-SPACE LINKS AND SPACE-TO-GROUND LINKS

The LEO spacecraft to a ground station down link operates at Ka-band frequencies (25.5-27.0 GHz)

V. KA-BAND LEO-TO-GROUND LINK HIGH POWER HIGH EFFICIENCY TRAVELING-WAVE TUBE AMPLIFIER (TWTA) FOR SPACE-TO-GROUND LINKS

International Space Station

LEO Spacecraft

White Sands Ground Terminal

Ka-Band with Pol 1

Ka-B

and

with P

ol 2

Relay Satellite

Multi-Access Antenna

Single Access Antenna

(4.9 m)

26 GHz

26 G

Hz

20.7

GHz

Space-to-Ground Link Antenna

(2.4 m)

13.

7 G

Hz

White Sands Ground Terminal

Intersatellite Link

Antenna (1.1 m)

https://ntrs.nasa.gov/search.jsp?R=20150022174 2020-02-25T17:09:48+00:00Z