OPS Forum Ka-band architecture Part1 05.10.2007

OPS-G FORUM, October 5th , 2007 Page: 1

26 GHz FREQUENCY BAND IN THE ESTRACK DEEP SPACE NETWORK

R. Abello, P. BessoOPS-GS


ESA upcoming missions Name Launch

dateOrbit Max

Range (1E6 km)

Max Ground Contact

hrs

Communications

Uplink Downlink

Downlink

DARWIN 2012 L2 1.5 12/24 X4 kbps

X10 kbps

KTo 1 Mbps

LISA 2015 Helio at 1AU

55 9/48 or 2.3/48

X2 kbps

X7 kbps

K28 kbps

EXOMARS 2013 Mars 400 X X

SoIO 2015 Helio Eccentri

c

270 9/24 X X 75 kbps

K or KaTo 1 Mbps

WFI 2015 L2 1.5 4/24 X X4kbps

K40-50 Mbps

FIRI 2020 L2 1.5 5/24 X X4kbps

K15 Mbps


NASA/JPL upcoming missions

Communications Coding Name Launch date

Orbit Max Range (1E6 km)

Max Ground Contact hrs Uplink Downlink Downlink Conv. Concat. or

Turbo SNAP 2014 L2 1.5 12/ 24 X K

300 Mbps X

LRO 2008 Lunar Polar

0.4 ? S S K 300 Mbps

X

SDO 2008 GEO 0.04 24/ 24 S 2 kbps

S 15 kbps

K 160 Mbps

X

JWST 2009 L2 1.5 12/ 24 (x) 3/ 24 (K)

S 16 kbps

S 40 kbps

X or K 8 Mbps or 28 Mbps

X

2013


Study Objectives

• Define K-Band mission requirements and to establish preliminary system specifications

• To develop a set of sub-system specifications based on the system specifications

• To investigate each major sub-system

• To investigate the optical/BWG solutions for each Deep Space Antenna (DSA1 and DSA2)

• To establish the feasibility of the introduction of K-Band reception into each of the DSA antennas


Frequency bands

• Ka-Band downlink 31.8 -32.3 GHz to be used for Deep Space Missions

• K-Band downlink 25.5 – 27.0 GHz to be used for Moon, Lagrangian and Near Earth Missions (including Earth Observation Missions)


Max Bit Rate for K Band with G/T = 55.4 dB/K

1.00E-02

1.00E-01

1.00E+00

1.00E+01

1.00E+02

1.00E+03

1.00E+04

1.00E+05

0.001 0.010 0.100 1.000

Range AU

Max

Bit

Rat

e -

Mb

ps

SNAP

JWST,WFI,FIRIDARWIN

LRO

LISA

SoIO (Base)

SoIO wish

Communication requirements analysis

• Need for 35m antennas• Need for cryo-LNAs• CD = 0.25 average clear weather


K-Band Sky Noise 1/3






K-Band Sky attenuation 1/2


K-Band Sky attenuation 2/2

• Impact of atmospheric attenuation on the link budget

• Important criterion for site selection of DSA3 in case 26 GHz is required


K Band Cryo LNA 1

K Band Cryo LNA 2

K Band FeedOMT/Polariser

K band DownConverter

X Band Cryo LNA 1

X Band Cryo LNA 2

X Band FeedOMT/Polariser

X band DownConverter

NB TTC Modem

NB TTC Modem

NB TTC Modem

Switching

X-Band HPA

X-Band HPA

X band Upconverter

X band Upconverter

X Band Diplexer

X Band Diplexer

L- band DownConverter

540-640 MHz LHC

540-640 MHz RHC

Antenna ServoDrive Antenna Control Unit

FRONT ENDCONTROLLER

High Rate Demodulator

High Rate Demodulator

70 MHz LHC

70 MHz RHC

70 MHz LHC

70 MHz RHC

LHC

RHC

LHC

RHC

LHC

Uplink

Uplink

Uplink

RHC

230 MHz Uplink

230 MHz Uplink

Wide Band Open-loop Ranging

ProcessorD/L

Uplink

BWGand

ANTENNA

Existing Equipment

K Band Equipment

New IFMS

LEGEND

DSP Baseband S/S

S Band Cryo LNA 1

S Band Cryo LNA 2

S Band FeedOMT/Polariser

S band DownConverter

Switching

S-Band HPA

S-Band HPA

S band Upconverter

S band Upconverter

S Band Diplexer

S Band Diplexer

L- band DownConverter

520-420 MHz LHC

520-420 MHz RHC

230 MHz Uplink

230 MHz Uplink

SWITCH

DSA1 Block Diagram


DSA1 antenna 1/8


Basic Philosophy

Present DSA1 design including K-band upgrade

University ofPavia

Antenna Optics, Dichroics & Feeds DSA1 Case – Darmstadt, Germany – 06/02/2007

DSA1 antenna 2/8

Maximum reuse concept:Dual reflectorLower BWG

Modifications limited to:M4New M4bNew feed in the upper BWG


DSA1 antenna 3/8

• Frequency: 25.5 – 27 GHz• Polarisation: Dual Circular• Tracking: K-Band


DSA1 antenna 4/8


DSA1 antenna 5/8


DSA1 antenna 6/8


DSA1 antenna 7/8


DSA1 antenna 8/8


Conclusions DSA1 upgrade

• Size of the M4 dichroic to be manufactured is big (3.2m x 1.75m)

• Sag of the dichroic mirror due to gravity

• Big down-time of the antenna in case the upgrade is required

• Poor G/T compared to the DSA2 upgrade

• DSA1 is the only Deep Space Antenna operating in S-Band. NASA/JPL Moon mission model considers the use of S- and K-Band simultaneosly.


DSA2 Block Diagram


Basic Philosophy

Present DSA2 design including KaTX-band upgrade

• Maximum reuse concept:

Dual reflector

Upper BWG

M5

Feeds (if applicable)

• Modifications limited to:

M6, M7, M8

Feeds

University ofPavia

Antenna Optics, Dichroics & Feeds DSA2 Case – Darmstadt, Germany – 06/02/2007

DSA2 antenna 1/8


DSA2 antenna 2/8


DSA2 antenna 3/8


DSA2 antenna 4/8


DSA2 antenna 5/8


DSA2 antenna 6/8


DSA2 antenna 7/8


DSA2 antenna 8/8


• Size of the M6 dichroic does not introduce any sagging on the surface

• Limited down-time of the antenna in case the upgrade is required

• Good G/T in K-Band compared to the DSA1 upgrade

• Mechanical and thermal feasibility of the dual frequency X/K-Band feed to be assessed. Performance in X-Band to be improved in order not to degrade the X-Band G/T wrt the existing design

Conclusions DSA2 upgrade


Post Amplifier Assembly

K BandRF OUT

Vacuum Dewar W /GW i n d o w C o u p l e r

B P FP o s tA m p

Test Input

B P F

HEMT LNA

B P F

HEMT LNA

X BandRF OUTP o s t

A m p

B P F

W /GW i n d o w

K B a n d 2 5 . 5 - 2 7 G H zI N P U T

X B a n d 8 . 4 - 8 . 5 G H zI N P U T

Test Input

K-Band LNAs

Noise figure requirement requires cryo-LNAs using state-of-the art HEMT (InP devices) which are not commercially available. A number of institutions are willing to develop HEMT amplifiers for this application. However, the main source of concern is how to obtain InP devices.


R. Abello presentation


Next steps

• Refinement of the analysis of the atmospheric propagation

• Development of the X/K-Band feed

• Development of cryo-LNAs covering the 26 GHz band

• Undertake breadboard level development of high speed front-end DSP boards based on FPGA technology

• Investigate technologies and design architectures in order to minimise group delay and amplitude distortion over very wide bandwidths


What are the other Agencies doing?

• 26 GHz band is the baseline for NASA Moon missions together with S-Band up- and downlink (future 21.55-22.55 GHz uplink).

• 26 GHz is the primary downlink of the James-Webb telescope

• NASA/JPL are currently upgrading their 34 m BWG antennas to 26 GHz downlink (2008 – 2010)


Technology

OPS Forum Ka-band architecture Part1 05.10.2007