Ascent Ground and Satellite Demonstration · 2018-02-15 · Ascent Demonstration- AMSAT Symposium Uplink-1 Receiver Downlink Transmitter ‘Satellite’ Computer • Receives Ground

Ascent Ground and Satellite Demonstration

By Ray Roberge, WA1CYB

& Howie DeFelice, AB2S

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• Place more capable satellites into higher orbits

• Utilize software defined radios

• A programmable transponder that supports multiple linear and

non-linear (FM) conversations simultaneously

• Digital modulation support

• Multi-users SHARING the Output Power

• Downlink assumed to be in X band (10.45 GHz), or greater

• Real time Doppler compensation

Big Picture Goals

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• C-Band Uplink, X-Band Downlink (five and dime)

• Provide Frequency/Time Locking Capability for the Ground Station

• Utilize SDR technology to maximize flexibility to Experiment and Modify Operation

• Optimize Satellite architecture to minimize Ground Station costs

• Provide for maximum Power Weighting @Output for the downlink to prevent satellite capture

• UHF/VHF/L-Band/S-Band/HF optional Uplinks

• Provide a Digital Downlink of Satellite Data

• Provide a Digital Downlink of ID, Time stamp, Location (ala GPS/Grid Square) and uploaded TLE

• Provide for a DVB-S2 Input & Output when available

• Build in Redundant paths where feasible

• Provide multiple Digital Downlink paths

• Provide multiple Voice Downlink paths with different modulation types

• Provide a Multi-channel In- Single Channel out for contact Initiation and/or emergency channel

• Provide a controlled Ham Band Scanner Survey Downlink Capability

Current Focus Goals

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Build and Demonstrate an example Ground and Satellite system that gives the user

a sense of what a modern satellite system might look and feel like

Concentrate on the system, not the implementation

Talk to me about GNU Radio flow graphs at the demonstration area

Incorporate the latest technology that is available and cost effective

Use hardware and software that is identical or mimics planned future systems

Make the communication architecture programmable to facilitate experimentation

and optimization

Use COTS SDR(s) likely to be used to facilitate early launch opportunities

General Approach

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Demonstration Approach

Satellite Demo:

Use available ETTUS SDR (N210) instead of the E310 or B205 that is desired.

Use a laptop running GNU Radio software with UBUNTU Linux

GNU Radio SW is loaded internally in the E310 version, but we needed a display

Use a cheap RTL-SDR as the second satellite receiver

Ground Station Demo:

Use available ETTUS SDR (N210) instead of the E310 or B205 that is desired.

Use a laptop running GNU Radio software with UBUNTU Linux

GNU Radio SW is loaded internally in the E310 version, but we needed a display

Use a cheap RTL-SDR as the local receiver in place of a microphone input

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Ascent Demonstration- AMSAT Symposium

Uplink-1Receiver

DownlinkTransmitter

‘Satellite’ Computer• Receives Ground Station C-band• Demodulates Uplink signals,

both Digital and Analog• Cleans them up and weights

them for retransmission• Adds frequency/time lock signal• Adds any cmd downlink and msg• Transmits to Ground (Downlink)

DownlinkReceiver

Local Receiver added &Tuned to VHF/UHFFor this Demonstration Only

LNB

Ground Station Computer• Receives Local Transmissions• Converts Audio for uplink• Transmits Audio(s) to ‘Satellite’• Receives Sat Sim via X-band• Processes received Data stream• Locks Frequency• Selects output channel(s)

LocalReceiver

UplinkTransmitter

~10.3 GHz

~0.6 GHz

What should be inside the SDR

Uplink-2Receiver

~5.6 GHz

0.44, 1.26, 2.4, 3.4 GHz bands

0.145, 0.44, 1.26 GHz bands

0.4 to 4.4 GHz

0.145, 0.44, 1.26 GHz bands

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3U Satellite Demo Connection Diagram (Commo)

Satellite Simulator Computer

• Boot to UBUNTU LINUX• Ascent Folder• Demo on Desktop

• Runs GNU radio /GRC

Patch

Up-ConverterOscillator 6 GHz

~

ETTUS SDR (XMTR)

0.4 to 4.4 GHz

Charger

5V Wart

SMA

SMASMASMA

Ground Node Computer

• Boot to UBUNTU LINUX• Ascent Folder• SDR-ConsoleV3 for testing• Demo on Desktop

• Runs GNU radio /GRC• 38+ Frequency “Channels”

LNB

Speaker

Avenger LNB

RTL-SDR(Rcvr)

Charger

18V Wart

Type-F

Type-F

Wire

SMA toMCX

SMA Atten

SMA Cable

Type-F toSMA

Type-F Cable

Dual DC PowerInserter

V

V

H

H

10.0 – 10.4 GHz

Pwr Strip

Pwr Strip

ETTUS SDR (Rcvr)

ETTUS SDR (XMTR)

SMA toMCX

SMA Atten

LPA

LPA

DCBlock

Local Receiver

5V Wart

5V Wart

RTL-SDR(Rcvr)

SMA toMCX

SMA Atten

RTL-SDR(Rcvr)

Vert.

Vert.

LO = 9.75 GHz

6 m to 23 cm

6 m to 23 cm

10.0 – 10.4 GHz

5.65 – 5.67 GHz

250 – 650 MHz

AC Power

AC Power

0.4 to 4.4 GHz

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Example Downlink Frequency Band PlanArbitrary Peak Weighting

NB

FMUSBLS

B

Ton

e L

ock

ing

Car

rie

r

WB-Digital

PSK

31

PSK

31

USB

0-19 -9

-31

-32

-33

-35-37

-128kHz

-83

128kHz

-25

1. Tone Locking Carrier: Enables Ground Lock of Spectrum when Doppler is present2. NBFM: Voice Channel(s) Translated from a Low Band3. USB: Combined Multi-channel In Initiate contact and/or emergency channel down4. BPSK: ID, Telemetry and data stream from satellite5. CW: CW Bandwidth(s) Translated from a Low Band6. PSK31-3: Satellite broadcast of ID, Time stamp, Location (ala GPS) and TLE7. PSK31-2: Chat Channel #28. PSK31-1: Chat Channel #19. USB: Channel #310. LSB : Channel #411. Wide Band Digital: Channel #512. Location Pulse(s): Enables Precise Ranging/Location

-30

BP

SK

PSK

31 C

W

Tim

e

Location Pulse(s)

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As Seen at Avenger LNB Output(Noise in at 5.5 GHz, Few channels enabled, Sat Out at 10.45 GHz)

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Example Channel Breakdowns

FrequencyTranslateAnd Filter




SquelchAGCFrequencyTranslateAnd Filter

Wgt

Weighted Linear Channel

FilterCTCSS

SquelchAGC

SquelchAGC

FilterSquelchAGC




Wgt

Wgt

Wgt

NBFMRcvr

NBFMXmit

Weighted FM Channel

Weighted PSK-31 Linear Channel

9600BPSK

Demod

9600BPSKMod

Weighted 9600 BPSK


SquelchAGCFrequencyTranslateAnd Filter

Wgt

DVB-S2 FDM/TDM Channel

FilterFrequency

ChannelizerDemod /

ModTime

Multiplexer

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Demo Ground Station

Local ReceiverTuned to a ham band RTL: freq. <1300 MHz

LNB

Speaker

SDR-Rcvr.1

0.25->1.0 GHz

FDM Channel Select

SDR-Rcvr.2

SDR-Xmtr

FrequencyLock

Time Lock

Chat Display

10->10.5 GHz

9.75 GHz LO

Voce and Data Recorded Message s

0.4 to 4.4 GHzUplink

UHF/VHF/L-Band

FilterSquelchAGC NBFMRcvr

NBFMXmit

Freq. DivisionCombiner

Chat Channel Select

De modulation

FrequencyDisplay

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• 2nd receiver can be tasked to do other functions• Conduct an Amateur Frequency Survey (multi-bands)• Examine propagation via WSPR and WJT modes• Upper atmosphere scattering• Urban noise sources versus frequency etc.• Multiple frequency inputs on different bands with common output band channel

(Cross band input) for emergency use. “Hoot and Holler” Conference call• Shared Aperture Antenna Steering• Automatic logging of satellite users/peak signal level /vs satellite location• Very weak satellite transmitter power beacon experiments (no power amplifier,

straight SDR power)• Even more satellite input frequency receivers (1 chip for each 2 frequency bands)• Harmonic beacons for frequencies above x-band…… endless possibilities!

Amateur Radio Science Experiment Possibilities

~5 Minutes to Transfer 1 Complete Set of Measurements Using 1 Output Channel

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Go See the Demonstration!• The Following slides show in a series of 5 test builds what the satellite could do• If you want to build your own system, start with the simplest linear satellite (sat_test_1)• Git-hub site has all the sat_test flow diagrams• Helpful Notes contained in the flow graphs

Sat-test_1.grc• Linear repeater +/- 128 kHz w/ single agc and squelch • CW tone at the output center frequency , f0out

• ID (cw) at f0out – 30.5 kHz• Pseudo Doppler available (As if in LEO or higher orbit)

Sat-test_2.grc• Sat_test_1.grc capability plus• Added nbfm channel at receive center frequency, f0in

• Added nbfm output at f0out-9 kHz• Squelch shown set low, Noise in nbfm Channel only• Audio enabled for demo purposes

Sat-test_3.grc• Sat_test_2.grc capability plus• Shifted 128kHz of input to f0in-62.5 kHz

Sat-test_4_r3.grc• Sat_test_3.grc capability plus• 250 kHz noise shifted up 12.5 kHz and attenuated 100 dB• Added 32 (30 useable) linear channels (1.95 kHz bw)

• Output 30 channels at f0out-125 kHz to f0out-62.5 kHz• Added 8 input channels (7 useable) linear channels (7.81 kHz bw)

• Lower edge if the bank at f0out-13kHz, upper edge at f0out-59 kHz• Note that cw ID is also placed in the lower part of the 3rd filter from nbfm• Second receiver (SR2) enabled• Linear output of SR2 placed in the 1st filter from nbfm

Sat-test_5.grc• Sat_test_4_r3.grc capability plus• Adjusted nbfm bw on receive• Added three psk31 transmit streams, 1kHz apart , each with ID text

• Three placed in 4th 7.81 kHz linear channel at ~f0out-40 kHz• Placed another psk31 stream on a reduced output upper stream

• Output frequency just under f0out-125 kHz• Maxes out current external computer resource used for development

https://github.com/WA1CYB/satellite_ground_emulator/tree/master/Ascent/Concept%20Demo%20System WA1CYB s13

sat_test_1_0.png



CW IDCD

Tone

Pseudo Doppler

TAB

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sat_test_1_1.png



Pseudo Doppler set

to LEO

Equivalent Doppler Simulation for both Input and Output

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sat_test_2_0.png

Sat-test_2.grc• Sat_test_1.grc capability plus• Added nbfm channel at receive center frequency, f0in• Added nbfm output at f0out-9 kHz• Squelch shown set low, Noise in nbfm Channel only• Audio enabled for demo purposes

nbfmCarrier

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sat_test_2_1.png


CW tone, cw ID and nbfmshifted w/ Doppler

Pseudo Doppler set

to LEO

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sat_test_2_2.png


nbfmModulation

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sat_test_3_0.png


Squelch set to -58 dB

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sat_test_3_1.png



Max GainUpper Noise apparent

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sat_test_3_2.png



Gain reduced 3 dB (.707 voltage)

Upper Noise < squelch

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sat_test_4_0.png

Sat-test_4_r3.grc• Sat_test_3.grc capability plus• 250 kHz noise shifted up 12.5 kHz and attenuated 100 dB• Added 32 (30 useable) linear channels (1.95 kHz bw)• Output 30 channels at f0out-125 kHz to f0out-62.5 kHz• Added 8 input channels (7 useable) linear channels (7.81 kHz bw)• Upper edge if the bank at f0out-13kHz, lower edge at f0out-59 kHz• Note that cw ID is also placed in the lower part of the 3rd filter from nbfm• Second receiver (SR2) enabled• Linear output of SR2 placed in the 1st filter from nbfm

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sat_test_4_2.png


Sat Receiver #2Signal received Spectrum shifted to

this output channel

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sat_test_4_3.png

Sat-test_4_r3.grcSat_test_3.grc capability plus250 kHz noise shifted up 12.5 kHz and attenuated 100 dBAdded 32 (30 useable) linear channels (1.95 kHz bw)Output 30 channels at f0out-125 kHz to f0out-62.5 kHzAdded 8 input channels (7 useable) linear channels (7.81 kHz bw)Upper edge if the bank at f0out-13kHz, lower edge at f0out-59 kHzNote that cw ID is also placed in the lower part of the 3rd filter from nbfmSecond receiver (SR2) enabledLinear output of SR2 placed in the 1st filter from nbfm

Spectrum shifted to this output channel

Zoomed in with greater resolution

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sat_test_4_4.png


Pseudo Doppler set

to LEO

Expect +/- 250 kHz in 600 seconds, Demo scaled to 30 seconds

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sat_test_4_6.png


Input Attenuation set to -20 dB, Squelch to -28 dB (so no nbfm)

Shows the six 7.8 kHz linear channels. One with

the cw ID added

Built in Test equipment Stack used.Wide Band Noise Applied to input

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sat_test_4_7.png


Input Attenuation set to -20 dB, Squelch down to -51 dB

Upper linear Channel Bank now visible

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sat_test_5_0.png

Sat-test_5.grc• Sat_test_4_r3.grc capability plus• Adjusted nbfm bw on receive• Added three psk31 transmit streams, 1kHz apart , each with ID text• Three placed in 4th 7.81 kHz linear channel at ~f0out-40 kHz• Placed another psk31 stream on a reduced output upper stream

• Output frequency just under f0out-125 kHz• Maxes out current external computer resource used for development !

Shows three psk31 channels sharing one

7.8 kHz channel

Upper psk31 channel sharing one 1.95 kHz

linear channel

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sat_test_5_1.png


• Output frequency just under f0out-125 kHz• Maxes out current external computer resource used for development!


linear channel

dB

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sat_test_5_2.png



Shows three psk31 channels sharing one 7.8 kHz channel

- Better resolution -

Upper linear Channel Bank not visible,

Not breaking squelch

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sat_test_5_3.png


• Output frequency just under f0out-125 kHz• Maxes out current external computer resource used for development! C

W ID

PSK

31

(s)

Upper linear Channel Bank not visible,

Not breaking squelch

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sat_test_5_4.png




linear channel, zoomed in

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sat_test_5_5.png



Squelch at -46 dBUpper linear channels noise over threshold

PSK31Visible

PSK31Visible

PSK31Not

Visible

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sat_test_5_6.png



Squelch at -40 dBUpper linear channels noise under threshold

PSK31Visible

PSK31Visible

PSK31Visible

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Go See the Demonstration!

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Operational Procedure- rev AOperation of the Ground Station

1 Warm up receiver and LNB

2 Run Frequency Calibration using ATSC pilots (Resulting error between 500 and 650MHz is less than 100 Hz

3 Turn GS receiver on SDR w/ LNB), input offset if needed

4 Turn GS C-band transmitter at known frequency and look for 2nd Harmonic in GS receiver SDR w/ LNB)

5 Measure Offset error and save, This is the LNB error + transmitter error + corrected SDR receiver error (GS error). Restart if required

6 Wait for Satellite, monitor beacon frequency range

7 After CW/Range beacon is visible, Center manually on the display. This is the GS error+ Satellite error + Doppler + Satellite frequency error

8 Subtract the GS error in step 5 from the measured frequency in step 7. This is the Satellite error + Doppler + Satellite frequency error

9 Turn on the Satellite error + Doppler + Satellite frequency error lock circuit

10 All receiver channels should be locked to the satellite and track it within +/-250Khz (LEO X-band)11 Transmit with selected offset (channel) on a unused channel12 Verify receiver picks up transmitter on frequency translation to X-Band.13 Antenna Rotation Control not demonstrated (this time)

Operation of the Satellite Station1 Warm up SDRs (Receiver and Transmitter)2 Bypass command structure and turn on system manually3 Enable CW/Range Beacon

4 Enable C-band receiver Band5 Enable Transmitter

System Operation Verification1 Use HT to talk to ground station on Channel zero

2 Verify reception on Channel zero on the Ground Station at X-band

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Documents

Ascent Ground and Satellite Demonstration · 2018-02-15 · Ascent Demonstration- AMSAT Symposium Uplink-1 Receiver Downlink Transmitter ‘Satellite’ Computer • Receives Ground