On-ground tests and measurements of the Passive Advanced Unit Synthetic Aperture (PAU-SA) Isaac...

On-ground tests and measurements of the Passive Advanced Unit Synthetic Aperture (PAU-SA)

Isaac Ramos Pérez, Thesis Advisor: Adriano José Camps Carmona

Barcelona Forum on Ph.D. Research in Communications, Electronics and Signal Processing

21st October 2010

Outline

• Introduction and objectives• PAU-SA’s concept• Work Plan• Potential improvements for future SMOS’s• PAU-SA’s processor• PAU-SA’s assembled process• Preliminary results• Conclusions

Barcelona Forum on Ph.D. Research in Communications, Electronics and Signal Processing 2v

Introduction and objectivesThe SMOS mission:o Retrieve global and frequent data of Soil Moisture and Ocean Salinity

o New kind of spaceborne Y-shaped aperture synthesis radiometer:

MIRAS (Microwave Imaging Radiometer by Aperture Synthesis)

o ESA Earth Explorer, Scheduled for 2010

Objective:o Test potential improvements for future MIRAS payloads New instrument:o Passive Advanced Unit - Synthetic Aperture (PAU-SA)o Award EURYI 2004 by A. Camps / Patented


PAU-SA concept

h,v sea surface roughness SST,T ( ), , SSS

PAU-RAD

PAU-GNSS-R

PAU-IR


Work PlanStudy

Potential Improvements

(Software)Simulator

(Mechanic)Mobile Unit

(Truck)

(Electronic)Device & test Assemble Full system’s

test

2006

2007

2008

2009

2010


Potential improvements for future SMOS’sParameter MIRAS/SMOS PAU-SA CommentsFrequency operation L-band (1400 - 1427 MHz) L-band (1575.42 MHz)

L1 of GPS signalSame frequency both Radiometry and

GPS ReflectrometryBandwidth 19 MHz 2.2 MHz Spatial correlation effects are

negligibleArm size 4 m 1.3 mAltitude Global observation, LEO, orbital altitude ground-based

Antenna type Patch antenna with V & H polarizations (not simultaneous)

Patch antenna with V &H polarization(simultaneous)

Full-pol(non-sequential)

Number of antennas per arm 23 8+1 (dummy) Improve G matrix condition number

Number total antennas 69 31

Antenna spacing0.875

at 1400 MHz, (21 cm)

0.816 at1575.42 MHz,

(15.5 cm)Increase the alias-free field of view

Receiver type single polarization (1 per element)

dual polarization(2 per element)

Full-pol(non-sequential)

Topology of the LO down-converter

Distributed LO (groups of 6 elements)

Centralized reference clock + internal LO generated in each receiver Reduce LO leakage and correlated

offset

Quantization1 bit IF sampling depending upon the noise

uptake level(Inside the LICEF )

8 bits IF sub-sampling using a external ADC

Used both digital I/Q demodulation (8 bits)

digital Power measurement (8 bits)

I/Q conversion Analog Digital Mass reduction.Elimination phase error

Frequency response shaped by Analog RF filter Digital low- pass filter

Mass reduction, quasi perfect matching, no temperature and aging

drifts Power measurement system

(PMS) Analog, using classical methods (diode) Digital (FPGA) Mass reduction, No temperature drifts

Calibration by Noise Injection Injection of Distributed noise Injection of Centralized noise PRN Simple calibration.

Calibration of non-separable errors

Image capabilities Dual-pol or full-pol (sequential) Full-pol(non-sequential)

Necessary to GNSS-R applications


PAU-SA processorSimulation

CharacterizationProcessing windowSource panel

Antenna panel


PAU-SA’s assembled process

Structure AutoCAD design and implementation

1.3 m

Mobile Unit AutoCAD design and implementation


PAU-SA’s assembled process• PAU-SA in Assemble process• Calibration and validation test

PAU-SA instrument during integration process

ADCs + FPGA(correlations and power estimation)

Master clockand buffers for

clock distribution


PAU-SA’s assembled process

1st Barcelona Forum on Ph.D. Research in Electronic Engineering 10

2008 2009 2010

2010 2010 2010

Preliminary results

Measurements at UPC anechoic chamber

Power variance versus number of samples

Normalized correlation (I and Q) vs. number of samples

Minimum Allan’s variance for power at 15 s → visibilities desnormalization

Minimum Allan’s variance for normalized correlations (real and imaginary parts) for 200 s

Real data: Single baseline response


Preliminary results3 s FFT

Point Source : PRN or toneMoving the Instrument

(without control temperature)

El +/- 10º,

+/- 20º

Az +/- 10º,

+/- 20º

Pol H Az= 0º El= 0º Pol H Az= +10º El= 0º Pol H Az= +20º El= 0º

Pol V Az= 0º El= +10º Pol V Az= 0º El= +20º

PRN Signal Rectangular filter


ConclusionsLong Project with different tasks:

– RF/FI Hardware designer - Digital Hardware: FPGA /PICs– Analog Hardware - Software programmer

(Simulator)– System Assembled and tested

– Director 5 PFCs (Coordination)– TEAM work, collaboration with:

– GUTMAR (Mobile Unit) Project– Funcadió Eduard Soler (Mobile Unit) Mechanic– Student designers – PAU TEAM (brainstorm meetings )– Several UPC personal

• Implementation of an end-to-end physically-based simulator for data acquisition & processing,

• PAU-SA’s instrument has been assembled and tested internally,

• Preliminary test with the instrument has been done successfully,


Thank you for your attention


On-ground tests and measurements of the Passive Advanced Unit Synthetic Aperture (PAU-SA) Isaac...

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