Zelinda Ireland Ltd Presentation to TeSAT 30 July 2008 Zelinda - - PowerPoint PPT Presentation

Presentation to TeSAT

30 July 2008

Zelinda Ireland Ltd

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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)

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Zelinda Proprietary Information

Zelinda Capability & Competitiveness

• Fully Focused on Space Communications:

– Specialised

• nly 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

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Zelinda Proprietary Information

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

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Zelinda Proprietary Information

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

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Zelinda Proprietary Information

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 Range Rate (m/s)

64404473.00 64404474.00 64404475.00 64404476.00

frequency (Hz) 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)

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Zelinda Proprietary Information

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

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Zelinda Proprietary Information

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 Sweep 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 Sweep 5.556 s (401 pts)

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

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Zelinda Proprietary Information

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

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Zelinda Proprietary Information

EDTE Demodulator for European Data Relay System

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

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Zelinda Proprietary Information

EDTE Demodulator for European Data Relay System

Overall Data Flow

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Zelinda Proprietary Information

User Spacecraft LIAU

Link to EDRS (LCT) EDRS Satellite DPU

Link to Ground Laser Link

EDRS DTE Anti-DPU Demodulation Anti-LIAU RF Link (Ka Band)

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

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Zelinda Proprietary Information

ESOC

EComTec

Entry, Descent and Landing COMmunications TECnology Study

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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

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Zelinda Proprietary Information

AR4JA LDPC Codec for ESOC’s TTCP

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Zelinda Proprietary Information

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

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Zelinda Proprietary Information

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)

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Zelinda Proprietary Information

FAT Transponder Breadboard

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Zelinda Proprietary Information

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

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Zelinda Proprietary Information

ABBM Modem - Overview

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Zelinda Proprietary Information CORDIC Rot XNCO CORDIC Rot

Freq Estimate Rate Estimate ΔØ Estimate

CORDIC Rot XNCO CORDIC Rot

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

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Zelinda Proprietary Information

CORDIC (vector) 16k point FFT

I Q

CIC Dec. CORDIC (vector) 16k point FFT

I Q

CIC Dec. 16k point FFT Peak search 16k point IFFT 16k point FFT Peak search 16k point IFFT Peak search Avg

• +

• Ch. 1
• Ch. 2

Swing buffer Swing buffer 16k point FFT of Tx Spectral Mask Threshold A Threshold A Threshold B

• Nb. of accumulations

NAcc Acc Mean

• +

Acc Mean

• +

Quarter band filter Quarter band filter Root Sum of Squares

÷

• Corr. Mag.

÷ ÷

Decimation factor NAcc

• Corr. Mag.
• Corr. Mag.

Phase diff. Carrier bin index Carrier

• freq. rate

Gain weights Normalize by sum

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

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Zelinda Proprietary Information

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

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Zelinda Proprietary Information

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.