# GPS Block IIR 3D model

> Shape built from published dimensions and pictures; details simplified.

Free 3D model of GPS Block IIR, a satellite, built from published dimensions by Space Radar. 8,768 triangles, 54 kB glTF, MIT.

- **Class:** Satellites
- **Mission:** Navigation
- **Triangles:** 8,768
- **File:** gps-iir.glb, 54 kB, glTF 2.0 binary (meshopt)
- **Look:** Flat colours
- **Size:** 11 m across
- **Made:** Built from dimensions
- **Added:** 2026-10-13
- **Download:** https://raw.githubusercontent.com/Sara-Managed-Projects/space-radar/main/site/models/gps-iir.glb
- **Mirror:** https://git.sara-agent.org/sara-projects/space-radar/raw/branch/main/site/models/gps-iir.glb
- **Viewer:** https://www.spaceradar.ai/model/?id=gps-iir
- **Licence:** MIT (https://github.com/Sara-Managed-Projects/space-radar/blob/main/LICENSE)
- **Credit:** GPS Block IIR 3D model by Space Radar (spaceradar.ai), MIT License

Canonical: https://models.spaceradar.ai/gps-iir/

## How it was made

Built in code from published dimensions and photographs, with no image-to-3D generator and no one else’s mesh. 3D model: built by Space Radar from published dimensions and a US government painting of a GPS Block IIR satellite.

built by this project in code (the private tool model-from-images: assemble.py, from a yaml of primitives), from the cited dimensions and the pictures under `references`; no image-to-3D model was used, and no published mesh (NASA's 3D Resources on GitHub, 1 583 paths read 2026-10-13, has none of this craft; the survey of 2026-10-13 found no agency model of it under usable terms)

## Dimensions

- Bus 1: 2.1 m
- Bus 2: 2 m
- Bus 3: 2.1 m
- Span: 11.4 m

Source: eoPortal, https://www.eoportal.org/satellite-missions/gps, OPENED 2026-10-13, 'Table 1: GPS Block specifications', columns Block IIR and Block IIR-M (the same numbers in both): 'Dimensions (m)' '2.1 x 2.0 x 2.1'; 'Span including solar arrays (m)' '11.4'; 'Primary Contractors' 'Lockheed Martin'; its text: 'they were based on the commercial AS-4000 bus'; 'UHF channel is used for cross-links between spacecraft'. Air & Space Forces Magazine, https://www.airandspaceforces.com/weapons-platforms/gps/, OPENED 2026-10-13: '(IIR/IIR-M) 5 x 6.3 x 6.25 ft, span incl solar panels 38 ft' (38 ft is 11.6 m: the span agrees within 0.2 m; its body is 1.5 x 1.9 x 1.9 m, smaller than eoPortal's, and eoPortal's is built). Lockheed Martin, 'GPS Block IIR and IIR-M Antenna Panel Pattern' (W. Marquis, 2014; published by the US Coast Guard Navigation Center, https://www.navcen.uscg.gov/sites/default/files/pdf/gps/GPS_Block_IIR_IIR_M_Antenna_Panel_Pattern_Marquis_Aug2015_revised.pdf, OPENED 2026-10-13), slide 6, 'GPS Block IIR Legacy Antenna': 'Used on first 8 of 12 IIR SVs'; '8 helix elements in circle with 4 elements in the center'; '12-way power divider and beam forming network'; slide 7, 'GPS Block IIR Improved Antenna': 'Used on final 4 of 12 IIR SVs, and all 8 IIR-M SVs'; 'New element designs and configurations on the panel'. The Navigation Center's page, https://www.navcen.uscg.gov/node/599, OPENED 2026-10-13: 'This is the Earth-facing panel providing the GPS L-band broadcast signal. The improved antenna panel includes redesigned L-band elements mounted on the SV Earth-facing structure in the same manner as the original legacy antenna panel.' THE FILE DRAWS THE LEGACY PANEL (eight round a middle four) for all twenty; the improved panel's own layout is in Lockheed's photograph, which is theirs and was not copied. NOT CITED, read off the government's painting: two panels a wing, the wing's width (1.75 m) and its yoke, the orange foil and the grey radiator windows, that the eight outer helices are fat and the four inner ones slender, the dark horn at the deck's corner, and the two lattice antennas on booms across the wing axis (TAKEN TO BE the UHF crosslink antennas: no page opened names them), whose size is the painting's.

## References

- [GPS-IIR](https://commons.wikimedia.org/wiki/File:GPS-IIR.jpg), US Government (gps.gov) (Public domain (US Government; US National Executive Committee for Space-Based Positioning, Navigation and Timing, gps.gov))