SDR & Ground Control Station¶
Last updated: 2026-05-22
Recent Finds¶
GNU Radio 4: Community Stewardship and the Road to 4.0 (GNU Radio Blog, May 21, 2026)¶
The GNU Radio project published a major governance clarification on May 21, 2026: GNU Radio 4 will continue as an officially community-maintained release line under GNU Radio's established governance structure, independent of GSI/FAIR's proposed alternative. The key development: the GNU Radio 4 core runtime and fundamental blocks are now MIT-licensed (previously GPL/LGPL). The stated rationale: MIT licensing "reduces barriers to adoption, integration, contribution, and deployment" across research, education, commercial, and amateur radio communities — a deliberate choice to accelerate ecosystem adoption over copyleft enforcement. Governance context: GSI/FAIR (the German heavy-ion research institute that has been a primary GR4 contributor) proposed an alternative governance model with LGPL licensing and different strategic priorities; GNU Radio declined and affirmed community ownership and neutral project identity. Both development lines will coexist with "clear project identities" to help users understand which release line they are adopting. Road to stable 4.0.0.0: the project is now focused on infrastructure, documentation, and testing for the first stable release — with an explicit invitation for community participation: testing, filing issues, writing examples, improving docs, building applications. Significance for aerospace SDR/GCS teams: (1) the MIT license is a significant change for commercial and governmental operators who previously avoided GR4 due to LGPL reciprocity concerns — the new license removes that barrier; (2) stable 4.0.0.0 preparation means the API is hardening, making now the right time for OOT module authors (including gr-satellites) to begin compatibility work; (3) the GSI/FAIR governance clarification removes uncertainty about which GR4 build to target. For CubeSat teams tracking GR4 adoption: this announcement is the clearest signal yet that GR4 will become the community's standard runtime — not a fragmented research branch.
GRCon 2026 CFP Now Open — Submissions Close June 13 (GNU Radio, April 3, 2026)¶
The Call for Participation for GRCon 2026 opened April 3, 2026, with a deadline of June 13, 2026. Conference dates: September 21–24, Raleigh NC, hosted by AERPAW at NC State (Talley Student Union). Registration also opened April 6. Submissions accepted: talks, papers, posters, and workshops. AERPAW's involvement makes this GRCon particularly relevant for aerial SDR, drone-assisted GCS, and aerial relay experiments — NSF-funded testbed combining drones (aerial SDR nodes) with programmable ground infrastructure. For satellite and rocketry teams: GRCon proceedings are a primary venue for new gr-satellites demodulator releases and SDR-based GCS architecture papers. gr-satellites GR4 status: no port underway yet — gr-satellites v5.10.0-git (March 2026, updated from v5.9.0 Dec 2024) still targets GNU Radio 3.10; block porting is explicitly listed as a community contribution need in the GR4 RC1 documentation and as a GSoC 2026 project idea.
ISL Technologies in LEO Networks: Comprehensive Survey (ScienceDirect, March 4 2026)¶
A peer-reviewed survey article (published March 4, 2026) covering the full landscape of inter-satellite link technologies for LEO constellations — covering RF ISLs, laser ISLs (LISLs), topology control, traffic scheduling, routing strategies, and GNSS integration. Key takeaway: LISL is now the dominant design direction for large-scale LEO constellations because shorter inter-satellite distances in LEO dramatically reduce transmission power and simplify the Pointing, Acquisition, and Tracking (PAT) problem vs. GEO. The survey synthesizes both the topology design challenge (static Grid-Mesh vs. adaptive TSU approaches) and the application layer (GNSS augmentation, 6G backhaul). Relevance for GCS/SDR practitioners: as ISL-equipped constellations proliferate, ground segment software must handle multi-hop routing and TM/TC relay scenarios — not just single satellite direct links — making ISL topology awareness a new requirement for GCS architecture design.
GNU Radio 4.0 RC1: C++23 Ground-Up Rewrite Reaches Near-Production Milestone (March 22, 2026)¶
GNU Radio 4.0 reached Release Candidate 1 on March 22, 2026 — the first near-production build of a ground-up rewrite in C++23. GR4 introduces three architectural changes relevant to aerospace SDR: (1) a plugin architecture with built-in reflection — block metadata is programmatically extractable, enabling automated validation pipelines and dynamic UI generation without manual schema maintenance; (2) SimdFFT — hardware-accelerated FFT via SIMD intrinsics, directly improving throughput for wideband signal processing on modern x86/ARM cores; (3) a deterministic scheduler designed to scale from embedded targets (Raspberry Pi-class) to HPC clusters, enabling the same flowgraph to run on a ground station laptop and a Kubernetes job without code changes. RC1 signals that aerospace teams can begin porting GR3 flowgraphs with confidence — the API is stable enough for serious evaluation. The upgrade path from GR3 requires flowgraph rewriting (not just recompilation), so the RC1 milestone is the trigger for projects to begin their migration planning. For CubeSat ground station teams: gr-satellites compatibility with GR4 is the practical gate — watch the gr-satellites GitHub for GR4 porting progress.
GRCon 2026 Confirmed: Raleigh NC, September 21–24, Hosted by AERPAW at NC State¶
GNU Radio Conference 2026 is confirmed for September 21–24 at NC State University's Talley Student Union, hosted by AERPAW (Aerial Experimentation and Research Platform for Advanced Wireless). Four full days of technical sessions, workshops, and demos. AERPAW's involvement is significant: it is an NSF-funded testbed combining drones (aerial SDR nodes) with programmable ground infrastructure — making GRCon 2026 particularly relevant for airborne SDR, drone-assisted GCS, and aerial relay experiments. GNU Radio is also participating in GSoC 2026 with project ideas spanning GPU acceleration and GNU Radio 4 porting. For satellite and rocketry teams using GNU Radio: GRCon proceedings are a primary venue for new gr-satellites demodulator releases and SDR-based GCS architecture papers.
SDA OCT Standard v3.2.0 + Space-to-Air Optical RFI (January 2026)¶
On January 28, 2026, the Space Development Agency issued an RFI for airborne optical communication terminals (OCTs) connecting aircraft directly to the Proliferated Warfighter Space Architecture (PWSA) LEO constellation — following a landmark August 2025 two-way space-to-air high-bandwidth optical link demonstration. Simultaneously, SDA released OCT Standard v3.2.0 (record standard for Tranche 3 satellites) alongside the advanced v4.0.0. Tranche 3 deployments predominantly use v3.2.0; a select subset will comply with v4.0.0. Initial operational capability for normalized space-to-air optical connectivity targeted as early as 2027. The PWSA ecosystem now explicitly covers three optical modality tracks: ground-to-space, space-to-space (ISL), and space-to-air — each with distinct standards and engineering requirements. Why this matters for GCS/SDR practitioners: the OCT standard is a published, versioned specification that defines the compatibility baseline for any terminal seeking interoperability with PWSA — more tractable than proprietary Starlink-style standards. The space-to-air track is the least mature and represents the most open engineering opportunity for small commercial actors.
Astrolight Greenland Optical Ground Station — Under Construction, Operational End-2026 (SpaceNews, 2026)¶
Lithuanian startup Astrolight, in partnership with ESA (ScyLight programme), has begun physical construction of the world's northernmost optical ground station at Kangerlussuaq, Greenland (~1,200 km from Pituffik Space Base). Not yet operational as of April 2026 — completion targeted end of 2026 (some sources cite summer 2026 for initial capability). Strategic rationale: all LEO orbital paths transit the Arctic, giving a Greenland OGS high contact frequency and extended pass duration for polar-orbit satellites — a geometric advantage no equatorial or mid-latitude site can replicate. Laser-based FSO communications deliver higher data rates and lower cost-per-bit than RF ground stations. Projected data transmission demand growing 14-fold over the next decade. Synthesis with SSC Space Santiago (already in this wiki): the optical GCS infrastructure layer is now multi-geographic — southern hemisphere (Chile), Arctic (Greenland), and space (Artemis II/MAScOT) — creating an emerging global optical relay backbone.
ISL Technology Survey: Hybrid Laser-Microwave Link Assignments for Navigation Constellations (Scientific Reports, 2026)¶
Survey of hybrid ISL architectures combining optical (laser) and microwave links in navigation satellite networks — directly applicable to GCS design decisions. The core finding: heterogeneous link topologies where intra-orbit links use laser (high bandwidth, stable geometry) and inter-orbit links use RF (flexible geometry, lower bandwidth but tolerant of larger pointing uncertainty) are architecturally natural for LEO/MEO satellites, not an engineering compromise. GCS implication: ground segment software must handle multi-link-type satellite data simultaneously — TM/TC routing logic for a constellation with hybrid ISLs is significantly more complex than single-link designs. For teams using Yamcs: federation (cascading upstream/downstream servers) becomes the natural architecture for multi-node hybrid-ISL constellations. Note on Yamcs: 5.13 has not yet released as of April 14, 2026; current stable is 5.12.6 (April 1, 2026). The Yamcs team is actively merging PR activity for the next cycle — watch the GitHub release page.
SatNOGS 12 Millionth Observation + Transporter-16 Deployment Support (SatNOGS Network, 2026)¶
SatNOGS crossed its 12 millionth observation milestone (milestone date: July 20, 2025), marking continued steady growth of the crowdsourced ground station network. In March 2026, the network demonstrated its operational value for commercial rideshare missions: 968 observations were scheduled within the first 24 hours of the SpaceX Transporter-16 rideshare deployment (March 30, 2026), providing immediate post-deployment tracking and telemetry for dozens of newly launched spacecraft. This highlights SatNOGS's evolving role beyond amateur CubeSat support into commercial rideshare validation — operators routinely rely on the SatNOGS network to confirm their satellites are alive and transmitting before their own ground stations acquire the first pass. Note: Yamcs 5.13 has not been released as of April 2026; current stable release is 5.12.5 (Feb 9, 2026).
Optical Ground Stations Go Operational: SSC Space Chile + MIT MAScOT on Artemis II (March–April 2026)¶
Two significant optical ground station milestones in Q1 2026. SSC Space brought its new Safran-built optical ground station in Santiago, Chile into operational service in March 2026, supporting up to 10 Gbit/s laser links with CCSDS/Space Development Agency-compatible modems and bi-directional capability — an actual operational deployment, not a demonstration. Concurrently, MIT Lincoln Laboratory's MAScOT lasercom terminal (2025 R&D 100 Award winner) launched aboard Artemis II in April 2026 (https://news.mit.edu/2026/lincoln-laboratory-laser-communications-terminal-launches-artemis-ii-0402), extending proven deep-space optical comms architecture to crewed lunar missions. Astrolight is also building a commercial optical ground station in Greenland targeting operational readiness by summer 2026. Synthesis: the optical GCS ecosystem is now multi-vendor and multi-geography — the infrastructure layer for laser-link ground support is maturing from prototype into operational commercial service.
Yamcs 5.12.x — April 2026 Release Cycle (v5.12.6, Apr 1 2026)¶
Yamcs reached v5.12.6 on April 1, 2026. Key additions across the 5.12.x series: full chart-tab reimplementation with customizable Y-axis zoom, raw parameter value rendering, and persistent chart config; collapsible sidebar; UTC/local time display toggle; Parameter Archive support in CSV exports; SDLS (Space Data Link Security) extended to non-UDP links; constraint-checking toggles for elevated-privilege operators; runtime-changeable XLS system names via YAML. Focus areas: operator ergonomics, SDLS security protocol coverage, and archive query flexibility — all operationally relevant for multi-mission ground segment operations. The cascading (upstream/downstream server federation) feature continues maturing. For CubeSat teams adopting Yamcs: the persistent chart config and Parameter Archive CSV export are the most immediately useful field improvements.
TinyGS vs. SatNOGS: Comparative Analysis of Open-Source Ground Station Networks (MDPI, 2026)¶
Peer-reviewed comparison of the two dominant open-source ground station networks. TinyGS leads SatNOGS in number of online ground stations and geographic distribution, and is cheaper and simpler to deploy (LoRa-based hardware vs. SatNOGS's SDR approach). Key operational difference: SatNOGS users schedule and execute observations themselves; TinyGS autonomously assigns satellites to stations by proximity — lower friction for casual contributors. SatNOGS retains deeper protocol flexibility and remains preferred for CubeSat telemetry collection, especially for UHF/VHF and non-LoRa satellites. As LEO small satellite launches accelerate, the paper argues a federated model drawing on both networks would be optimal — relevant for student mission operators choosing between the two for ground support infrastructure.
SatNOGS-COMMS: ESA-Backed Open-Source CubeSat Radio Subsystem (Libre Space Foundation / SmallSat Europe 2025)¶
Libre Space Foundation + ESA co-developed SatNOGS-COMMS: a complete open hardware/software communications subsystem for CubeSats, drop-in compatible with the SatNOGS global ground station network. Full-stack integration: the hardware ships with demodulation and decoding that feeds directly into the SatNOGS Network dashboard, with mission control for telecommand and real-time telemetry visualization. Supports AX.25, CSP, and CCSDS framing. For any university CubeSat team, this is now the path-of-least-resistance from radio hardware to fully integrated GCS without building custom decoder chains.
GNU Radio GSoC 2026: Hardware-in-Loop CI for Real RF Testing (GNU Radio Blog, March–April 2026)¶
GNU Radio was accepted as a GSoC 2026 mentoring organization, with one active proposal thread covering hardware-in-loop continuous integration — automated testing with real radio hardware (SDRs connected to CI runners) rather than purely simulated signal paths. The project aims to measure BER and signal detection accuracy under real RF conditions, with CorteXlab proposed as a candidate hardware-CI platform. This is technically significant: existing GNU Radio CI tests are entirely software-simulated, meaning propagation effects, ADC nonlinearity, and driver-level behavior are untested. A merged hardware-in-loop CI would directly benefit downstream OOT modules like gr-satellites and gr-satnogs, which depend on hardware-specific timing behavior that software simulation cannot capture. No GR4 port for gr-satellites has been started as of April 23 — the GR4 porting is itself a separate GSoC 2026 project idea but no mentor-student match confirmed yet.
The apex MCC: Blueprint of an Open-Source, Secure, CCSDS-Compatible Ground Segment (MDPI, Sep 2025)¶
The most complete public blueprint for a production-ready Yamcs-based GCS stack, validated on the MAPHEUS-10 sounding rocket (live commanding between Sweden and Germany). Architecture: fully containerized, CCSDS TM/TC handling, broker-based publish-subscribe messaging (separating data producers from consumers), SLE (Space Link Extension) protocol bridging for professional ground network integration, and 2FA-secured VPNs — all open source. Key value: it closes the gap between "we use Yamcs" and an actual production-grade, secure ground segment design. Transfers directly to CubeSat and small lander missions with minimal adaptation. MAPHEUS-10 validation gives it rare real-flight credibility for an open-source GCS design paper.
Software Defined Radio (SDR)¶
What It Is¶
Traditional radio: hardware circuits define the modulation, filtering, and frequency. SDR: all signal processing is done in software — the hardware is just an ADC/DAC + RF front-end.
Antenna → RF front-end (LNA, mixer, bandpass) → ADC → [FPGA/CPU] → Software (GNU Radio / custom DSP)
Key Hardware¶
| Device | Freq Range | ADC bits | Notes |
|---|---|---|---|
| RTL-SDR v4 | 500 kHz – 1.75 GHz | 8-bit | $30, receive only, best entry point |
| HackRF One | 1 MHz – 6 GHz | 8-bit | TX+RX, half-duplex |
| LimeSDR Mini 2 | 10 MHz – 3.5 GHz | 12-bit | TX+RX, full-duplex, open hardware |
| USRP B210 | 70 MHz – 6 GHz | 12-bit | TX+RX, full-duplex, industrial grade |
| PlutoSDR | 325 MHz – 3.8 GHz | 12-bit | Analog Devices, good for learning |
For satellite work: LimeSDR or USRP — 8-bit isn't enough dynamic range for weak signal work.
Software Stack¶
- GNU Radio — visual flowgraph-based DSP. Industry standard for SDR prototyping.
- SatNOGS — open-source global satellite ground station network, runs GNU Radio under the hood.
- GPredict — satellite tracking + Doppler correction integration with GNU Radio.
- gr-satellites — GNU Radio blocks for decoding amateur/CubeSat telemetry frames (AX.25, KISS, CSP).
- OpenSatCom — open framework for satellite communications ground segment.
Key Concepts for Satellite Links¶
Link Budget — calculates if your link closes (received power > noise floor):
EIRP (dBW) - FSPL (dB) + Gr (dBi) - Losses = Received Power (dBW)
Margin = Received Power - Receiver Sensitivity
- EIRP = Tx Power + Tx Antenna Gain
- FSPL = Free Space Path Loss = 20·log₁₀(4πd/λ)
- Gr = Receive antenna gain
- Margin > 3 dB = acceptable; > 6 dB = comfortable
Doppler Shift for LEO satellites (~400–600 km): - Max shift at horizon: ±10 kHz at 437 MHz (UHF) - Must track and correct in real-time — GPredict → Hamlib → radio/SDR
Common Frequencies: | Band | Freq | Usage | |------|------|-------| | VHF | 144–146 MHz | Uplink (command) for amateur sats | | UHF | 430–440 MHz | Downlink (telemetry) for amateur sats | | S-band | 2.0–2.4 GHz | High-rate downlink, imaging satellites | | X-band | 8–10 GHz | High-rate (100 Mbps+), ground station networks |
Ground Control Station (GCS)¶
Architecture¶
[Tracking Antenna] ← AzEl rotator (Hamlib) ← [Rotator Controller]
↓
[SDR / Radio transceiver]
↓
[Modem layer: AX.25 / CCSDS / custom]
↓
[Mission Control Software]
↓
[Mission Database] ← [Telemetry Processing] → [Alerts / Visualization]
← [Telecommand (TC) queue]
Protocols¶
- AX.25 — packet radio protocol, standard for amateur satellites. Simple, mature, 1200/9600 baud.
- CCSDS (Consultative Committee for Space Data Systems) — standard for professional missions. Defines Space Packet Protocol, CFDP (file transfer), TM/TC frames.
- CSP (CubeSat Space Protocol) — lightweight, CAN/I2C/UART/RF agnostic. Like TCP/IP for CubeSats.
- KISS — Keep It Simple Stupid. Thin framing layer between TNC and software.
Open Source GCS Software¶
| Software | Language | Notes |
|---|---|---|
| OpenMCT | JavaScript | NASA open-source mission control framework |
| COSMOS | Ruby | Ball Aerospace, professional grade, complex |
| Yamcs | Java | ESA-backed, production-ready, CCSDS native |
| SatNOGS Network | Python/Django | Crowdsourced, 100+ ground stations globally |
| FlatSat | Python | Lightweight for CubeSat testing |
Yamcs is the best open-source option for a real mission — CCSDS compliant, telemetry archiving, commanding, and has a REST API.
Antenna Considerations¶
- Yagi-Uda: high gain, directional, needs tracking rotator. Best for UHF/VHF LEO.
- Helix: circularly polarized, good match for satellite polarization rotation.
- Dish/Parabolic: high gain, S/X-band, requires precise pointing.
- Turnstile/Eggbeater: omnidirectional, no tracking needed, lower gain — for initial AOS.
For a basic CubeSat ground station: dual-band Yagi (VHF+UHF) + AzEl rotator + RTL-SDR/LimeSDR + GPredict + GNU Radio + gr-satellites.
Core Concepts¶
TM/TC (Telemetry & Telecommand)¶
- Telemetry (TM) — data from satellite to ground: housekeeping (temp, voltage, current), payload data
- Telecommand (TC) — commands from ground to satellite: mode changes, payload activation, orbit maneuvers
- CCSDS TM Space Data Link Protocol — standard framing for TM
- CCSDS TC Synchronization and Channel Coding — standard for TC
Link Security¶
- Authentication: HMAC or ECSS PUS service 11 (time management) + service 3 (housekeeping) have auth fields
- Encryption: rare in amateur class, standard in professional (AES-256)
- Replay protection: sequence counter + timestamp validation
Open Questions¶
- What's the minimum cost hardware setup to receive LEO CubeSat telemetry reliably?
- How does SatNOGS handle scheduling conflicts across the global station network?
- What's the state of optical (laser) ground-to-space links for small satellites?
- DTN (Delay-Tolerant Networking) — is Bundle Protocol (RFC 5050) mature enough for CubeSat missions?
- SatNOGS-COMMS targets CubeSat missions — does it support full-duplex S-band or is it VHF/UHF only? What's the max downlink rate?
- GRCon 2026 CFP open (April 3 – June 13): which gr-satellites developments and SDR-based GCS papers will be submitted? Will a gr-satellites GR4 porting project be announced?
- gr-satellites GR4 port: no work started as of April 2026 — GR4 porting is listed as a GSoC 2026 project idea, which may trigger community activity.
- CANVAS confirmed operational (April 16, 2026): first VLF science results will appear at conferences 2026–2027. What are the initial wave directionality findings?
Yamcs 5.12.6 Latest — 5.13 Still Unreleased (April 18, 2026)¶
Confirmed April 18, 2026 via GitHub: Yamcs latest release is 5.12.6 (April 1, 2026). Version 5.13 has not been released. The 5.12.x release cadence continues: 5.12.4 Jan 26, 5.12.5 Feb 9, 5.12.6 Apr 1. gr-satellites latest is v5.9.0 (December 14, 2025) with no GNU Radio 4 targeting release — GR4 porting remains a community contribution need and GSoC 2026 project idea.
gr-satellites v5.10.0-git — Documentation Updated March 11, 2026; No Stable Tag Yet¶
Confirmed via readthedocs as of April 21, 2026: the gr-satellites documentation now shows v5.10.0-git with a documentation build date of March 11, 2026 — confirming active development continues post-v5.9.0. No tagged v5.10.0 stable release exists on GitHub. The v5.9.0 stable release (December 14, 2025) remains the production baseline. GR4 (GNU Radio 4, C++23 rewrite, RC1 released March 22 2026) compatibility remains the major open question — gr-satellites still targets GNU Radio 3.10 exclusively. GR4 porting is listed as a GSoC 2026 project idea; the GRCon 2026 CFP (open through June 13, September 21–24 Raleigh NC) is the next inflection point where any porting progress will likely be announced. For operational CubeSat ground stations: stay on GNU Radio 3.10; do not assume GR4 compatibility before an explicit announcement. Yamcs status unchanged: 5.12.6 (April 1, 2026) is latest, no 5.13 release.