Zelinda Ireland Ltd Presentation to TeSAT

Presentation to TeSAT

30 July 2008

Zelinda Ireland Ltd

2 Zelinda Proprietary Information

Zelinda Company Background

• Incorporated in 2000

• Fully Focused on Space communications

• Based in Waterford, in the South East of the Republic of Ireland

• Ownership

– 67% with the founding directors

– 33% with Celestia STS (the Netherlands)


Zelinda Capability & Competitiveness

• Fully Focused on Space Communications:

– Specialised

• only DSP (inc ADC & DAC) & architecture around DSP

– DSP Designs are predictable (spuriae, noise) “all design – no development”

– Innovative algorithms & Architectures

• Using sampling schemes that move aliases out of band

• One bit sampling and dither (simple, provides automatic ALC)

– Innovative Implementations

• Deep understanding of algorithms allows simplification of implementation

• Combining successive DSP blocks into single entity (eg Interpolator & Upconvertor)

• Several functions provided by single Module (eg FFT does DCAAS Dynamic Channel Activity

Assignment System & Rx Channelisation)

• Scaling to minimise quantisation noise & hence number of bits ( eg in sinewave LUTs)

• Hardware and Software implementations


Project & Custom Base

Project Prime Contractor Customer

IFM MDA JAXA

KaTE Transponder Astrium Ottobrunn ESTEC

BEM modem Callisto EuMetSat

TTC Transponder Honeywell ESA / Fomosat / LuxSpace

NRX Zelinda ESTEC

NMDU SSBV Galileo

Ka-Antenna Upgrade Callisto ESOC

TTCF Modem SSBV Galileo

Galileo DST Transponder Tesat (Backnung, DE) Galileo

C-Band Transmitted DU Honeywell Exact Earth

EDTE Modem SSBV Airbus

Protocol Arpsoft ESOC

EcomTec Study Callisto ESTEC

AR4JA LDPC Codec BAE Systems ESOC

FAT Transponder Honeywell ESTEC

ABBM Modem Celestia STS ESTEC

VHDR Tesat (Backnung, DE) ESTEC


Novel Range Rate Experiment (NRX)

• Contracted to ESA ESTEC

• Objective to prove the reliability and accuracy of a Zelinda Proprietary

Non-Coherent two way range rate measurement technique.

• Design & Development of a ground demodulator to measure

groundstation integrated Rx & TX carrier phase which together with

spacecraft Integrated Rx & TX carrier phase yields range rate &

spacecraft Tx frequency.

• KaTE Ka band Tx Power only 20 mW hence ground demodulator

designed to track down to C/No 16 dBHz.

• Experiment conducted during Lunar insertion


KaTE Range Rate Results

Comparison of Range Rate Measurements (Time Interpolated - Independent measurements at 1 second intervals)

580.000

590.000

600.000

610.000

620.000

630.000

640.000

07:30:00 08:00:00 08:30:00 09:00:00 09:30:00 10:00:00 10:30:00 11:00:00

Time

Ra

ng

e R

ate

(m

/s)

64404473.00

64404474.00

64404475.00

64404476.00

fre

qu

en

cy

(H

z)

X Coherent

X Non-Coherent

Ka Coherent

Ka Non-Coherent

X Coherent KaTE Fo Reference

X Non-Coherent KaTE Fo Reference

Ka Coherent KaTE Fo Reference

Ka Non-Coherent KaTE Fo Reference

• Agreement between conventional coherent and novel non-coherent better than 1.1 μm/s (31 second average)

• Measurement noise less than 0.160 mm/s (31 second average)


S & X Band Transponder

• Developed Jointly with Honeywell (UK)

• Flexible Rx Modulation schemes and data rates

• PCM/BPSK/PM, SP-L/PM, SP-L, or BPSK upto 1 Mbps

– Flexible Tx Modulation schemes and data rates

• BPSK, SPL, SRRC OQPSK (32k – 6.25 Mbps)

– Flexible RF frequencies & Tx Power

• RX/TX channel frequency user selectable (synthesized LOs controlled by Privileged Commands)

• Joint architectural design with Honeywell

• Zelinda designed FPGA

– Innovative one-bit IF sub-sampling receiver concept

• Thermal noise (or added dither) used to linearise

• 5 times over sampled WRT signal bandwidth

• IF around “n -1/5” of sampling rate (not ¼)

• Sampling at high IF of 190 MHz where SAW Rx filter small & lower loss

• Single stage Rx downconversion

• FPGA based (Actel RTAX)

– Coherent Turnaround and Tx SRRC filtering in Digital domain

– Digital upconversion to first Tx IF


S & X Band Transponder Tx

10:53:50 Jun 8, 2006

Ref -14 dBm Atten 5 dB

Samp

Log

10

dB/

VAvg

10

W1 S2

S3 FC

AA

Center 25 MHz

#Res BW 3 kHz #VBW 1 kHz

Span 1 MHz

Sw eep 416.7 ms (401 pts)

200 kbps SRRC OQPSK

14:05:17 Feb 23, 2006

Ref -10 dBm #Atten 0 dB

Mkr1 2.10 MHz

-60.01 dB

Peak

Log

10

dB/

V1 S2

S3 FC

AA

Center 25 MHz

#Res BW 3 kHz #VBW 3 kHz

Span 20 MHz

Sw eep 5.556 s (401 pts)

1

1R

5 Mbps SRRC OQPSK

> 25 delivered :

Formosat, Esail, M3M, Cheops, Innosat….

DST – Dual Standard Galileo TTC Transponder

Initially aimed at Galileo FOC Satellites: • DSSS – 2 kbps Rx & 50 kbps Tx using TDRSS 1023/261,888 long codes

• Rx - PCM/BPSK/PM using 16 kHz Subcarrier, Tx using BPSK/PM using 252 kHz subcarrier

• Transparent ranging channel supporting ESA standard code/tone ranging with TC echo suppression

• Exact Coherency (with configurable turnaround ratio)

Developed to include • X-Band or S-Band versions

• FM receive

• BPSK receive

• SPL/PM receive

• SPL Tx

• BPSK Tx upto 6 Mbps

• SRRC OQPSK Tx upto 12 Mbps


DST – Dual Standard Galileo TTC Transponder

Zelinda designed FPGA in VHDL.

• 70 MHz Rx IF sampled at 40 Msps

• 140 MHz Tx IF sampled at 200 Msps

• Parallel correlator implemented in time domain for DSSS code acquisition

• Control and monitoring via serial interface

• Implemented in Microsemi RTAX FPGA without multipliers

44 units now flying


EDTE Demodulator for European Data Relay System

• EDRS is multiple GEO satellites providing data relay from LEO satellites to Earth.


EDTE Demodulator for European Data Relay System

Overall Data Flow


User Spacecraft

LIAU

User Frame

User Frame

LIAU Frame LIAU Frame

Part of User Frame Part of User Frame

Link to

EDRS

(LCT)

EDRS Satellite

DPU

DPU Frame

Part of LIAU Frame

Part of User Frame

Link to

Ground

Laser Link

DPU Frame

Part of LIAU Frame

Part of User Frame

EDRS DTE

Anti-DPUDemodulation Anti-LIAU

RF Link (Ka Band)

DPU Frame

Part of LIAU Frame

Part of User Frame

DPU Frame

Part of LIAU Frame

Part of User Frame

LIAU Frame LIAU Frame

Part of User Frame Part of User Frame

User Frame

User Frame

Zelinda Designed & implemented 2.4 Gbps (4 channels x 600 Mbps) OQPSK FPGA

Demodulator using 1.2 Gsps processing 8 samples in parallel.

Operated down to Es/No < -1.0 dB with implementation loss < 0.25 dB

Protocol – Prototype Offline Correlator

• Open-loop recorded signals from 2/3/4 Deep Space antennas are combined at ESOC to improve

received SNR.

• Zelinda developed C++ program implementing “Sumple” Algorithm to acquire and track relative phases

and delays of signals.

• Developed with Arpsoft (Italy).

• Successfully tested using Cebreros (Spain) and Malargüe (Argentina) with both

• Mars Express and ExoMars


ESOC

EComTec Entry, Descent and Landing COMmunications TECnology Study

14 Zelinda Proprietary Information Example EDL phase from ExoMars 2016

EComTec Entry, Descent and Landing COMmunications TECnology Study

• Intended for Direct to Earth communications at X-Band from Probe with very

high Doppler dynamics during EDL and low gain omni antenna.

• Low data rate “Special MFSK” modulation scheme developed by JPL using

Carrier phase modulated by square wave at tone frequency. Supports Low data

rates - 1 to 8 bps.

• Zelinda developed a Joint detection scheme for carrier and sidebands offering a

7.3 dB performance improvement over JPL scheme. Supported 2 bps at C/No

= 16.5 dBHz


AR4JA LDPC Codec for ESOC’s TTCP


TTCP

Altera Stratix V

LDPC

Codec

LDPC provides > 1 dB better than Concatenated Conv/RS

Developed as a

self contained and

independent

“plug-in”

Used Sum Products Algorithm with Min*() combining at Check Nodes.

Bit true and delay true C++ model developed and validated first.

C++ model adapted to include automatic writing > 6000 lines of VHDL code.

AR4JA LDPC Decoder


CCSDS standard developed by JPL provides 9 combinations:

• 3 information block sizes 1024, 4096 and 16364 bits

• 3 code rates. ½, 2/3, 4/5.

Aimed at Deep space, but higher code rates than Turbo.

Performance using 350 MHz clock in Altera Stratix V:

• BER Within ~0.02 dB of reference curves for < 200 iterations

• 25 Mbps for k = 1024 with 50 iterations

• 13 Mbps for k = 4096 with 100 iterations

• 6 Mbps for all block sizes with 200 iterations

• Multiple decoders with elastic buffering used to provide > 75 Mbps

FAT Transponder

Flexible Autonomous Transponder Bread board • X & Ka Band

• Autonomous Acquisition without ground station sweep using FFT

• Autonomous reacquisition of data modulated signal

• DSSS acquisition using frequency domain parallel correlator

• Autonomous Rx Modulation scheme detection: – DSSS

– SPL/PM

– PCM/BPSK/PM with subcarrier,

– BPSK.

• Autonomous data rate detection using SSME algorithm

• In flight adjustable Rx and Tx channels and coherency ratio

• Regenerative PN Ranging, Transparent ranging, DSSS ranging

• One way range rate

• Flexible TM Downlink Modulation schemes (Subcarrier, SPL, BPSK, OQPSK, GMSK, DSSS)


FAT Transponder Breadboard


ABBM Modem

Advanced Base Band Modem

• Aimed at constellations and EGSE

• 4 channels including diversity combiner

• Fast Carrier & Diversity acquisition using FFT

• Supports 2 subcarriers per carrier

• Currently under development

20 (2) Zelinda Proprietary Information

ABBM Modem - Overview


CORDICRot

XNCO

CORDICRot

Freq Est imate

Rate Estimate

ΔØ Estimate

CORDICRot

XNCO

CORDICRot

Prediction

PE & Mag

PE & Mag

ΣØ Loop Filter

Weighted ΔØ1 , ΔØ2 ΣØ, OCR

ΔØ1

ΔØ2

Weighted Complex

Sum

OCR SC Demod

SC Demod

OCR Estimate

CIC

CIC

SP-L Demod

I

Q

Tone Ranging

ESA Ranging

Integrated Carrier Phase

(to Range Rate)

PPS

PPS

Integrated Carrier Phase Predict (to

Range Rate)

Mon FIFO

Mon FIFO

Mon FIFO

Mon FIFO

Mon FIFO

Mon FIFO

Mon FIFO

Power detector & AGC

Ch.1 input

gain control

Power detector & AGC

Cross Correlator& Power (SCA)

Ch.0 baseband complex samples

Ch.1 baseband complex samples

Fs=180 MHz

Ch.0 input

gain control

Remnant Carrier coarse

freq. acq. module

• 3 independent demodulators (above x 3)

ABBM Modem - Initialisation


CORDIC(vector)

16kpointFFT

I

Q

CICDec.

CORDIC(vector)

16kpointFFT

I

Q

CICDec.

16kpointFFT

Peaksearch

16kpointIFFT

16kpointFFT

Peaksearch

16kpointIFFT

Peaksearch

Avg

Mag

Mag

-

+Phase 0

Phase 1

Ch. 1

Ch. 2

Phase diff.

Swingbuffer

Swingbuffer

16k point FFT of Tx Spectral

Mask

Threshold A

Threshold A

Threshold B

Nb. of accumulationsNAcc

Acc

Mean

-

+

Acc

Mean-+

Quarter bandfilter

Quarter bandfilter

Root Sum of Squares

÷

Corr. Mag.

÷

÷

Decimationfactor

NAcc

Corr. Mag.

Corr. Mag.

Phase diff.

Carrier bin index

Carrier freq. rate

Gain weights

Normalize by sum

Norm. Ch.2 corr.

Norm. Ch.1 corr.

Gain weighting by SNR

Select carrier from

channel with

highest corr. to mean

noise mag. ratio

• Diversity Combination initialisation

• Carrier Frequency Acquisition

Power Spectrum

Averaged Power Spectrum

Correlation of mask with

Averaged Power Spectrum

VHDR Very High Data Rate Receiver


Receiver for Lunar Relay Satellite in Near Rectilinear Halo Orbit (NRHO)

• Autonomous Symbol rate and Code rate detection

• SRRC OQPSK modulation scheme

• LDPC AR4JA codes (rates ½, 2/3 4/5, k = 16384)

• Symbol rates 10 – 100 Msps


Conclusion

• Zelinda have pre-existing tested VHDL modules to do many Transponder

and Ground Modem functions.

• This VHDL is flexible and adaptable to different architectures (sampling

rates, data rates, performance trade-offs)

• Zelinda is experienced in both DSSS and conventional Transponders and

Ground Modems.

• Expertise includes Ranging (Tone/Code, RPN) and LDCP coding.

• Zelinda have designed several transponder digital units supporting multiple

modulation schemes (SUT, Galileo, FAT).

• Zelinda offer a low risk route to successful project completion.

Documents

Zelinda Ireland Ltd Presentation to TeSAT