Ground segment

Also known as Ground station, Mission operations, SatNOGS, Ground network

The stations, networks, software and people that talk to a satellite. Small missions combine their own station with open networks such as SatNOGS; a mid-latitude station sees a 525 km Sun-synchronous orbit about three times a day above 10°.

Document
SQ-OP-002
Updated
20 Oct 2026
Reading time
5 min
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Definition#

The ground segment is everything on Earth that operates a spacecraft: antennas and radios, the network that links them, the software that plans passes, decodes frames and archives telemetry, and the operators. For a small mission it is often the part the team underestimates, although every byte of the mission passes through it.

Stations and networks#

A typical amateur-band station for a UHF PocketQube combines a crossed-Yagi antenna on an azimuth–elevation rotator, a low-noise amplifier (LNA) at the mast, a software-defined radio and a computer that steers the antenna from current orbital elements and tunes the receiver for . Omnidirectional antennas such as quadrifilar helices or turnstiles need no rotator but give up about 11 dB of gain.

No single station sees a low-orbit satellite for long, so missions in amateur bands rely on networks. , the Satellite Networked Open Ground Station project of the Libre Space Foundation, links hundreds of volunteer stations through an open scheduler and database[1]. For every observation it archives a waterfall image of the received spectrum, an audio recording, demodulated frames and, where a decoder exists, decoded telemetry[2]. Open demodulators such as gr-satellites[3] and declarative decoders written in Kaitai Struct[4] let anyone turn those recordings into data.

The Grizu-263A ground segment#

Grizu-263A was operated from the ZBEÜ station at Zonguldak Bülent Ecevit University, SatNOGS station 1184 (Maidenhead locator KN51vk, 41.452° N, 31.762° E, 120 m, 10° elevation mask), commissioned in December 2019 by receiving KISS-framed telemetry from the CHOMPTT CubeSat[5]. Licensed radio amateurs supervised the student operators, supported by TAMSAT, the national amateur satellite association. The telemetry formats were published without encryption, and its Kaitai decoder in the SatNOGS database decoded the 31 telemetry fields automatically[6], so stations around the world contributed data for 21 months.

References

  1. [1]White, D. J., Giannelos, I., Zissimatos, A., Kosmas, E., Papadeas, D., Papadeas, P., Papamathaiou, M., Roussos, N., Tsiligiannis, V., & Charitopoulos, I. (2015). SatNOGS: Satellite Networked Open Ground Station. Valparaiso University, Engineering Faculty Publications 40.scholar.valpo.edu
  2. [2]Libre Space Foundation. (2026). SatNOGS DB — satellite and transmitter database.db.satnogs.org(accessed 20 October 2026)
  3. [3]Estévez, D. (n.d.). gr-satellites: a GNU Radio out-of-tree module with decoders for amateur satellites.github.com(accessed 20 October 2026)
  4. [4]Kaitai Project. (n.d.). Kaitai Struct: a declarative language for describing binary data structures.kaitai.io(accessed 20 October 2026)
  5. [5]nadir lab. (2026). PocketQube picosatellites: A review of standards, mission trends and miniaturization constraints, with lessons learned from Grizu-263A, Türkiye’s first PocketQube [Preprint]. nadir lab.Read on nadir lab.
  6. [6]Libre Space Foundation. (2026). SatNOGS DB: Grizu-263A (NORAD 51025).db.satnogs.org(accessed 20 October 2026)
  7. [7]Friis, H. T. (1944). Noise figures of radio receivers. Proceedings of the IRE, 32(7), 419–422.doi:10.1109/JRPROC.1944.232049
  8. [8]ITU-R. (2026). Recommendation ITU-R P.372-18: Radio noise. International Telecommunication Union.itu.int(accessed 20 October 2026)
  9. [9]Kahr, E., Montenbruck, O., & O’Keefe, K. (2013). Estimation and analysis of two-line elements for small satellites. Journal of Spacecraft and Rockets, 50, 433–439.doi:10.2514/1.A32352
  10. [10]Alonso, R., & Shuster, M. D. (2002). Complete linear attitude-independent magnetometer calibration. The Journal of the Astronautical Sciences, 50, 477–490.doi:10.1007/BF03546249

Cite this SatWiki entry

@misc{nadirlab2026ground,
  author       = {{nadir lab.}},
  title        = {{Ground segment}},
  year         = {2026},
  month        = oct,
  howpublished = {nadir lab. SatWiki SQ-OP-002 (Rev. 1)},
  url          = {https://nadirlab.space/en/wiki/ground-segment/}
}