GPS message format Sub- frame Word Description 1 1–2 Telemetry and handover words (TLM and HOW) 3–10 Satellite clock, GPS time relationship 2–3 1–2 Telemetry and handover words (TLM and HOW) 3–10 Ephemeris (precise satellite orbit) 4–5 1–2 Telemetry and handover words (TLM and HOW) 3–10 Almanac component (satellite network synopsis, error correction)