Proto-Flight Model of SAR for 100kg Class Small Satellite
Hirobumi Saito – Synspective Inc.; Jiro Hirokawa, Takashi Tomura – Tokyo Inst of Technology; Prilando Rizki Akbar – Keio University; Budhaditya Pyne – Synspective Inc.; Koji Tanaka, Makoto Mita – JAXA; Tomoki Kaneko – The University of Tokyo
1
2
Contents
1.Introduction 2.SAR System Overview 3.SAR Antenna Thermal & Mechanical Test 4.SAR Antenna RF Test 5.High Power Amplifier 6.Mission Data Storage & Down Link 7.Conclusion
This research was funded by ImPACT Program of Council for Science, Technology and Innovation (Cabinet Office, Government of Japan).
Acknowledgement
3
TERRASAR-X 2007, 1230kg
X
Active Phased Array Antenna several hundreds of TX/RX module. High cost.
15m
3m
Honeycomb Panel Slot Array Antenna. Small stow size. Low cost
XSAR
Recent SAR Small Satellites ICEYE, Finland ICEYE-X1 Jan 2018, 80kg
Active Phased Array. TX/RX Module
Capella Space, USA 2018 launched , <40kg
Canted two Planer Membranes with reflect array
5
Altitude 618km 618km
Resolution 3 1m
Swath 10 km 10 km Chirp Band Width 75MHz 300MHz
Polarization
NESZ (beam center) -20dB -16dB Ambiguity (beam center)
SAR Mode
1545 deg 3000 7000TBD) Hz
>15dB
SAR
SAR

SAR SAR m


100kg
130kg





SAR


1
5
(1m (3m


15

35km x35km () 35 km ()
45° 30km300km60km600km



3110.7mx0.7m

130MH




GaN2200W6
ICD




X350Msps, 64APSK, 22Gbps





EM51%68%, PFM7,70%, directivity 44.5dBi
300MH

7-11dB

40kg
E- 29.9kg

>1.97Hz >81Hz
BBM 1.81Hz PFM 78Hz

PFM7EM

1mmRMS
0.2mmRMS0.4mmRMS0.7mmRMS,
1.1mmRMS 0.6mmRMS (case5) 0.51mmRMS x1.8 =0.92mm, 0.08mmrms. 1.2mmRMS

10 ±40
(Case3) -7(case5) 11(Case3) -7060


GaN2200W6













/







EM


TByte
DR



1.5Gbps


XPD>B
XPD>B


10mX

IM-PR-T2-17008A 1Hz 60Hz 1mmRMS

20151020 10/1910/16 ⇒ ⇒ ⇒ () ⇒() ()
WBS
ICD
SAR


RF()




SAR


SAR SAR m


100kg
130kg





SAR


1
5
(1m (3m


15

35km x35km () 35 km ()
45° 30km300km60km600km



3110.7mx0.7m

130MH




GaN2200W6
ICD




X350Msps, 64APSK, 22Gbps



-

0.6 dB
NESZ
-20dB
-16dB
-
Ambiguity
>15dB

0.15
0.2
0.05x2
1


0.2
Circulator
0.4
1.2
NF
LNA
1

(0.9 m)
0.15




• – NF – 3dB – • • ANT • 0.8 dB – • • 1.2 dB – • 1dB
F=(S/N)in/(S/N)out=(Nout/Nin)/G=(Nadditive+GNin)/(GNin) Nadditive=GNin(F-1)=kToBG(F-1)=kTnoise*B kTnoise B=kTo BG(F-1) A) =To(F-1)=Tin F=1+Tin/To LT LkTB /L) kTB=kTB(1/L)(L-1) , =(1-1/L)kTB=kTB(1/L)(L-1) B) A)B)L1/LF* kTB(1/L)(L-1)=kToB(1/L)(F*-1) F*=(T/To)(L-1)+1 L,Tno L F*=(T/To)(L-1)+1 L L TBTB/L kTB(1/L)(L-1) TBLTB(1/L)L-1TBL)L-1TBTBLSNL F=(S/N)in S/Nout = L
20181216 T L)kTBkTB1/LSNLF=L LNALNA
0.3+0.2+0.5=1.0dB=1.26 LNANF=1.5dB=1.43 NF=F1+(F2-1)/1/L) =1.26+(1.43-1)/(1/1.26)=1.802=2.56dB

L/N




1

7 0.7×0.7 [m](1)

2


6
SAR
0
-2.26
hinge angle 0.4mm rms
accuracy of hinge angle is <0.01deg. Total 4 hinge angels are independent.
thermal deformation 0.7mm
others
(mm rms)
(deg)
±λg
0
±10.3
0
-0.11
0
±1.5
0
-0.02
0.5
6
6
-0.05
-0.05
0.2
0.1
0.2
1
-0.2
-0.2
0.4

EM
PM
PM

BBMk
EM
EM
PM
PM
EM
PM
EM
EM
BBMk
EM
EM
EM
PM
EM
PM
PM
PM
PM/
PM


FPGA
EM
EM
EPM
PM

EM
EM
PM


(kg)

130
ALOS
50
840
UAV
710
8000
19

BBM
EM
PM











BBM
EM
PM



BBM
EM
PM



SAR
600km
SAR
.

15


SLIM Cell
LAPS
string#2
PL
SUMITA Cell
PL

0.04mm >43dB


WGSAR-ANTRFE
BPF
TX()
LIMAM
0.8 dB( BPF=0.2[dB],CIR=0.3[dB],WGANT-BPF=0.2[dB ])

0.7[m]4.9[m]50[%]0.7[m]×4.9[m]43.49 [dBi] ()A:ANTANTB:C:D:ADANT 50%A0.4[dB] 2.5[m]0.15dB/mB0.1[dB] ISASHFSSC0.1[dB]10.05BISAS1320.05×20.1[dB]D0.1[dB] 1.2[dB]
6
LNA
LiIon Bat power 1.2kW
Stored & Radiated 0.9kW Heat
Freq.Conv
NAND Flash
SAR Image Processing
Honeycomb Panel Slot Array Antenna
Aluminum Skin Sheet
Radiation Slot
All Electrical Instruments in Satellite body. Antenna panels are passive just components.
5m
15cm
Radiation Slot
Honeycomb Slot Array Antenna
Choke Flange
Waveguide Tournament Feeder
Flexible solar cell sheets are on rear side of panels.
(NOMEX +)
(Al )
MLI
SAP()
Low Loss Waveguide Tournament Feeder Solar Cell Sheet on Rear side of Antenna
8
Heat from solar cell is shielded by MLI. Rigid support panel is installed to reduce thermal distortion.
Low Loss X-band Feeding By Waveguide Tourment Circuit
5m
9
Rear SideSolar Cell SheetFront SideAntenna
Thermal Distortion DesignThermal Design
Thermal Simulation Thermal Distortion
Simulation
MLI
Thermal Distortion < 0.7mm rms
Flexible Solar Cell Sheet
Thermal Distortion Design & Test
11
11
7-Panel Antenna Array Near-Field Measurement
Amplitude
Phase
5m
5m
Full FM Antenna ( 5mx0.7m ) Kyoto University, AMETLAB Near Field Test Facility. Raw Data
Uniform amplitude/phase excitation is expected in design. However manufacturing error results in ~30deg phase unbalance.
12
-8 -6 -4 -2 0
-12 -8 -4 0 4 8 12 Elevation Angle (deg)
FF A
m pl
itu de
(d B
FF A
m pl
itu de
FF P
ha se
(d eg
Far Field Antenna Pattern from Near Field Measurement
Phase variation in main lobe is several degree.
Uniform amplitude /phase excitation. Side lobe level -13dB.
Elevation
13
-8 -6 -4 -2 0
-1.5 -1 -0.5 0 0.5 1 1.5
FF A
m pl
itu de
(d B
AZ Narrow Angle Pattern
30deg Phase unbalance between panels increases in Side lobe level.
0
10
20
30
40
FF P
ha se
(d eg
FF A
m pl
itu de
(d B
Azimuth
14
28
30
32
34
36
38
40
42
44
46
9.35 9.4 9.45 9.5 9.55 9.6 9.65 9.7 9.75 9.8 9.85 9.9 9.95
7-Panel Array Directivity (dBi) vs Frequency (GHz)
FM #3M FM #2M FM #1M FM #0 FM #1P FM #2P FM #3P FM 7Panel Calculated FM 7Panel EM 4Panel 20% 30%
FM 7 panel and EM 4 panel: Kyoto log peri Nlamda w/o corection factor. FM single panel: Toko-dai OEWG with correction factor. Kyoto measurement seems to be higher 0.7dB than Toko-dai from comparison of #3P.
EM 4-panel

1kW output (200W x 6-combiner), on-duty 25% 5 min operation. Heat is stored Al satellite panel.
1kW GaN X band Power Amplifier
1kW X-Band Amplifier
XPA RF
[sec]

[d B
[sec]

Elapsed Time(sec)
R F
Po w
er (d
16
1kW X band GaN Power Amplifier on Aluminum Panel as Heat Sink
1kW, 25% on duty X band GaN Power Amplifier on Aluminum Panel that works as Heat Sink and Radiator
17
Ground Test of SAR Response from Point Source (S-ELU Hardware + Target Simulator)
SAR Mode Slant Range Resolution
Ground Range Resolution
Off Nadir 30deg
Sliding Spot Light 0.47 m 0.86 m
Measured Range Resolution
-2 -1.5 -1 -0.5 0 0.5 1 1.5 2
Range [m]
Azimuth [m]
range [m]
Slant Range
TX Timing Echo Signal
Strip Map: 75MHz chirp,600km Synthetic aperture time 0.56sec Sliding Spot Light : 300MHz chirp, 300km, rotation range 533.57km Synthetic aperture time 0.76sec
18
RHCP
LHCP
2-3Gbps in X band
19
X band Transmitter, 300Msps, LHCP/RHCP Dual Channel 64APSK/16APSK Non-Real Time Software Demodulation.
LHCP 16APSK(26/45), 670Mbps
RHCP 64APSK(11/15), 1270Mbps
20
64APSK
Satellite Down Link Speed
Symbol Rate Modulation rolloff
(Dia / Tsys) Hodoyoshi-4
13.5dBi 3.8m/120K
Rapis-1 (2019)
64APSK 0.05 315MHz 1W Corrugated Horn 17dBi 10m/55K
ISAS/JAXA Heritage of High Speed Down Link for Small Satellite
ISAS/JAXA Heritage of High Speed Down Link for Small Satellite
Standardization with oversea stations
32APSK
1.Developed unique SAR system for low cost, 100kg class satellite.
-honeycomb panel slot array antenna -non-contach waveguide feeding with choke flange -GaN 1kW, 25% on-duty amplifier, 5min operation
2.Ground resolution 3m, and 1m with limited NESZ. 3.Massive SAR data storage and X-band down link.
2 Gbit/sec down link was experimentally demonstrated by Rapis 1 satellite in Feb., 2019.
4. The SAR satellite demonstration will be in 2020 by Synspective Inc.
Presented in Session V, Aug.5, 2:30PM, T.Obata
Slide Number 1
Compact Honeycomb Panel Slot Array Antenna & Non-contact Waveguide Feeding
Low Loss Waveguide Tournament Feeder Solar Cell Sheet on Rear side of Antenna
Thermal Distortion Design & Test
Slide Number 14
Slide Number 15
High Speed Down Link Experiment by RAPIS-1 Satellite