| name | is-gps-200n |
| description | Knowledge base from IS-GPS-200 Rev N (NAVSTAR GPS Space Segment / Navigation User Segment Interfaces). Use as a worked ICD/IS exemplar: what an interface specification is, DIST-A and IRN/CCB change control, interface definition vs identification, composite-signal criteria patterns, NAV data as payload families, and time/definition hygiene. Covers Rev N synthesized notes only; does not transcribe Apps II–IV bit fields or PRN/Gold-code tables, and does not replace faa-std-025 preparation rules. |
NAVSTAR GPS Space Segment / Navigation User Segment Interfaces (IS-GPS-200N)
Source: IS-GPS-200 Rev N (cover 01-AUG-2022) (US Government work, public domain, DIST-A) | Chapters: 6
When to use
Reach for this pack when you need a worked Interface Specification / ICD — how a live IS defines RF links, identifies codes and NAV payload, writes interface-criteria shalls, and keeps time/definition hygiene — complementary to faa-std-025 (how to prepare an IRD/ICD, not a live ICD).
Prerequisites: none — plain Markdown; no MCP server, API key, or licence tier needed at runtime.
How to Use This Skill
- Without arguments — load the core frameworks below.
- With a topic — ask about ICD-as-contract, IRN/CCB, L1/L2 criteria, LNAV vs CNAV families, URA/CEI, or which appendix to open.
- With a chapter — ask for
ch01 through ch06.
Supporting files: glossary.md, patterns.md, cheatsheet.md.
Core Frameworks & Mental Models
Document-as-contract
An IS states the Space Segment / User Segment interface. It does not alter contracts or purchase orders (cover notice). Users implement against numbered shalls; exceptions live in Appendix I letters, not in silent receiver folklore.
Definition → identification → criteria
- Definition (3.1) — what the interface is (L1 and L2 RF links carrying ranging codes + NAV data to a user with RF visibility).
- Identification (3.2) — which codes and data families exist, and that they are CDMA-separated.
- Criteria (3.3) — measurable shalls (frequency plan, levels, phasing, polarization, time).
Change / IRN discipline
ICC prepares PIRNs; ICWG has 45 days; GPS Directorate CCB (with DOT representing civil/public interest) makes the IS effective. Rev N incorporates IRN-IS-200M-001 (RFC-467). Distribution status changed to Public Release on an earlier revision.
Payload vs bits
Body text names LNAV D(t) and CNAV DC(t) families. Bit layouts, FEC polynomials, and PRN tables live in Apps II–IV — open those only when implementing a decoder, not when learning ICD structure.
Chapter Index
| # | Section | Key content |
|---|
| ch01 | IS Scope and Change Control | What an IS/ICD is; DIST-A; ICC/ICWG/CCB/IRN |
| ch02 | Definition vs Identification | L1/L2 contract; code families; document-as-contract |
| ch03 | Interface Criteria Pattern | Frequency, levels, phasing, polarization as shalls |
| ch04 | NAV Data as Interface Payload | LNAV/CNAV families, not bit fields |
| ch05 | Time and Definition Hygiene | GPS time / Z-count; URA; CEI; reserved/invalid |
| ch06 | Appendices as a Map | When to open App I–IV; do not dump payloads |
Topic Index
- CCB / PIRN / IRN → ch01
- CEI data set → ch05
- Change / IRN → ch01
- CM (configuration of the IS) → ch01
- CNAV / LNAV families → ch04, ch06
- DIST-A / public release → ch01
- ICD / IS → ch01, ch02
- Interface criteria (RF pattern) → ch03
- Interface definition vs identification → ch02
- Interface Management → ch01, ch02
- PRN / ranging codes (as identifiers) → ch02, ch06
- Requirements Traceability → ch02, ch03
- Reserved / invalid / dummy SV → ch05
- URA → ch05
- Z-count / GPS time → ch05
Supporting Files
Scope & Limits
This pack covers IS-GPS-200 Rev N (cover date 01-AUG-2022; public-release revision record) as synthesized reference notes from the official gps.gov PDF (248 pages per extraction metadata). It is an ICD exemplar, not a signal-processing dump: Apps II–IV bit fields, PRN/Gold-code tables, and FEC polynomials are not transcribed. It complements faa-std-025, which teaches IRD/ICD preparation rules (outlines, VRTM, FAA CM) and is not itself a live ICD — same slug-distinction pattern as dote vs dod-te-guidebook. It does not ingest IS-GPS-705J, IS-GPS-800J, ICD-GPS-153, or a non-existent IS-300. US Government public domain work (DIST-A). No source-material download link is published.
