Also known as: Galileo
Galileo is the European Union’s global satellite navigation system and a member of the GNSS family, notable for being the first such system built under civilian rather than military control.1 Like GPS and BeiDou it shares one L-band frequency across all satellites using code division (CDMA), and a receiver fixes its position by multilaterating ranges to four or more satellites.
Overview
Galileo is a constellation designed for a full complement of 24 operational satellites (plus spares) in three medium-Earth-orbit planes at about 23,222 km. It provides several services: a free Open Service for mass-market positioning, a High Accuracy Service delivering decimetre-level corrections, and an encrypted Public Regulated Service for government and safety-of-life users. Its E1 Open Service is deliberately placed on the same 1575.42 MHz carrier as GPS L1 so a single antenna and front end can receive both.
Technical characteristics
| Property | Value |
|---|---|
| Access | CDMA |
| Carriers | E1 = 1575.42 MHz, E5a/E5b ≈ 1176–1207 MHz, E6 |
| Modulation | CBOC (E1), AltBOC (E5) — offshoots of BPSK spreading |
| Satellites | 24 operational + spares, three MEO planes |
| Altitude | ~23,222 km |
| Distinctive | First civil-controlled GNSS; SAR relay payload |
Galileo’s binary-offset-carrier (BOC/CBOC) modulation splits signal energy away from the band centre, which sharpens the correlation peak and improves multipath rejection compared with the simple BPSK spreading of legacy GPS C/A — one reason multi-constellation receivers value it. Galileo satellites also carry a COSPAS-SARSAT search-and-rescue relay payload and can even send a return-link acknowledgement to a distress beacon.
History
Galileo grew out of European ambitions in the 1990s for a navigation system independent of the US military-run GPS. The first test satellites flew in 2005–2008, initial services began in December 2016, and the constellation reached near-completion in the early 2020s, with a second generation of satellites in development.
Deployment
Galileo is used everywhere modern GNSS chips are used — its signals are tracked alongside GPS, GLONASS, and BeiDou in virtually every current smartphone and survey receiver. Its High Accuracy Service and tight time reference make it attractive for precision agriculture, surveying, and timing.
Decoding it with GopherTrunk
GopherTrunk does not decode Galileo. Satellite navigation in the L-band is outside the scope of a VHF/UHF land-mobile trunking scanner. Galileo can be received by a general-purpose software-defined radio with an active antenna and low-noise amplifier — and because its E1 signal overlaps GPS L1, the same capture can hold both — but turning that into a position fix needs dedicated GNSS software, not GopherTrunk. Any relevance to GopherTrunk is limited to GNSS as an external timing reference.
Sources
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Galileo (satellite navigation) — Wikipedia, for Galileo’s civil governance, service tiers, E1/E5 signals and BOC modulation, orbit, and the search-and-rescue payload. ↩