Meteor M2 Satellite Image Decoder

Overview

The capstone project: a complete satellite ground station that receives and decodes weather images from Russian polar-orbiting Meteor M2 satellites. This project demonstrates mastery of digital communications, DSP, and system integration at a professional level.

This is particularly compelling for aerospace and RF employers—it demonstrates the ability to design complete digital communications systems from theory to working hardware.

Signal Characteristics

• Frequency: 137.1 MHz or 137.9 MHz
• Modulation: QPSK (Quadrature Phase Shift Keying)
• Symbol Rate: 72 ksps or 80 ksps (satellite dependent)
• Bandwidth: ~120 kHz
• FEC: Convolutional (K=7, R=1/2) + Reed-Solomon
• Protocol: LRPT (Low Rate Picture Transmission)

System Architecture

RF Chain: QFH Antenna → LNA → SAW Filter → RTL-SDR

Digital Chain: USB → Zynq ARM (sample streaming) → FPGA fabric

FPGA Processing: DDC → RRC Filter → QPSK Demod → Viterbi → Deinterleave → RS → Frame Sync → Image

Implementation Phases

Months 19–20: QPSK Demodulator

• Matched filter (root-raised-cosine for ISI elimination)
• AGC (automatic gain control)
• Carrier recovery (Costas loop or PLL)
• Symbol timing recovery (Gardner algorithm)
• Symbol decision with soft outputs

Months 21–22: Forward Error Correction

• Viterbi decoder (K=7, R=1/2, 64-state trellis)
• Convolutional deinterleaver
• Reed-Solomon RS(255,223) decoder

Months 23–24: Protocol & Image

• CCSDS sync word detection
• Frame alignment state machine
• Virtual channel demultiplexing
• LRPT data extraction and image reconstruction
• HDMI display or PC streaming

Skills Demonstrated

• QPSK Demodulation: Carrier and timing recovery loops
• Viterbi Decoding: Soft-decision convolutional decoding
• Reed-Solomon: Block error correction
• Protocol Implementation: CCSDS and LRPT from specification
• Complete System Design: RF to image pipeline

Hardware Requirements

• RTL-SDR V3 or V4 (~$35–50 NZD)
• LNA optimized for 137 MHz (~$15–25 NZD)
• SAW filter 137 MHz bandpass (~$10–15 NZD)
• QFH antenna (DIY from PVC/coax, ~$20–30 NZD)

Final Deliverables

• Complete GitHub repository with modular, documented code
• Block diagram of complete system architecture
• Individual testbenches for each major module
• Simulation results showing demodulation performance
• Gallery of received satellite images
• Video demonstration of live satellite pass reception
• Resource utilization and timing reports
• Technical write-up explaining design decisions

Architecture

Architecture will be documented as the project progresses.

Implementation Notes

Implementation notes will be added during development.

Resource Utilization

To be measured after implementation.

Progress Log