ADS-L, FANET, FLARM or ADS-B: what are the differences?
ADS-L, FANET, FANET+, FLARM, ADS-B and Mode S are not synonyms: they are distinct technologies, born from different needs and carried by different ecosystems (free flight, gliders, light or commercial aviation). A single device may combine several of them, but none alone covers all uses. This comparison summarizes what each one transmits, receives, and who it is primarily designed for.
| Technology | Transmits (Out) | Receives (In) | Main use | Widely present among | Direct air-to-air communication | Possible infrastructure |
|---|---|---|---|---|---|---|
| ADS-L | Depends on device | Depends on device | ADS-L is a lightweight electronic perceptibility standard, designed for low-cost, low-power devices. | Light aviation and free flight (including paragliding), notably in Switzerland via the FASST-CH plan | Yes | Yes |
| FANET | Yes | Yes | FANET is a communication network developed for free flight, enabling the exchange of position and small data between equipped pilots. | Paragliding and hang gliding | Yes | Yes |
| FANET+ | Yes | Depends on device | FANET+ combines the FANET network and FLARM compatibility, depending on the device's implementation. | Paragliding and hang gliding seeking interoperability with FLARM-equipped gliders | Yes | Yes |
| FLARM | Depends on device | Depends on device | FLARM is a proximity perceptibility and alert system historically very present among gliders. | Gliders, light aviation, part of equipped free flight | Yes | Yes |
| ADS-B | Depends on device | Depends on device | ADS-B is the surveillance and perceptibility standard used by commercial aviation and a large part of general aviation. | Commercial aviation and general aviation | Yes | Yes |
| Mode S | Depends on device | Depends on device | Mode S is a surveillance transponder used notably in powered aviation — it is not simply a synonym for ADS-B. | Powered aviation | Depends on implementation | Yes |
The exact features depend on each device. An instrument may, for example, transmit ADS-L without receiving it, or receive FLARM without transmitting it. "Possible infrastructure" means that a ground relay is documented or planned for this technology (for example the FASST-CH architecture for ADS-L, or the OGN network for FLARM/FANET) — this does not guarantee total or permanent coverage, nor that two aircraft will automatically perceive each other.
ADS-L vs FANET
ADS-L is a lightweight electronic perceptibility standard, designed for low-cost, low-power devices, with interoperability designed for a wide range of light aircraft. FANET is a network specific to free flight, allowing the exchange of position and small amounts of data between equipped pilots. Both meet different needs and can be present on the same device without one replacing the other.
ADS-L vs FLARM
ADS-L transmits (and, depending on the device, receives) the position of an aircraft according to a standard designed for interoperability between types of light aircraft. FLARM is an older system, widely present among gliders, which adds on compatible devices a trajectory calculation and a proximity alert. FLARM and ADS-L can coexist on the same device: one does not replace the other.
ADS-L vs ADS-B
Despite the resemblance of the acronyms, ADS-L is not a miniature variant ofADS-B. The two standards differ in their technology, their ecosystem and their regulatory framework. ADS-B is the standard used by commercial aviation and a large part of general aviation, while ADS-L targets low-cost, low-power light aircraft, particularly in free flight.
FANET vs FLARM
FANET is a community network specific to free flight; FLARM is a proximity perceptibility and alert system historically very present among gliders, with its own trajectory calculation functions on compatible devices. A FANET-only device is not natively compatible with the FLARM ecosystem — this is precisely what FANET+ adds.
FANET+ vs FANET
FANET+ is not a simple marketing rebranding of FANET: it combines the basic FANET network and FLARM compatibility, the extent of which depends on each manufacturer's implementation. In Switzerland, the current recommendation communicated for free flight combines FANET+ and ADS-L Out — one does not replace the other, the two complement each other.
FLARM vs ADS-B
FLARM and ADS-B are two distinct ecosystems, born from different needs: FLARM is historically very present among gliders, with its own trajectory calculation on compatible devices, while ADS-B is the surveillance standard used by commercial aviation and a large part of general aviation. An aircraft with ADS-B Out broadcasts its identity, position and flight data; an aircraft with ADS-B In receives that of others, without one automatically implying the other.
Should you choose a single system?
Generally not. Modern devices can combine several technologies to improve their interoperability. However, this depends on each device and the practice concerned — paragliding, gliding or motorized aviation do not have the same uses nor the same dominant ecosystems — and the choice of an instrument should be based on its actual capabilities, verified on its technical sheet, rather than on the idea that combining more protocols would in itself be enough to improve safety.
Frequently Asked Questions
No. ADS-L is an electronic perceptibility standard designed for interoperability with a wide range of light aircraft, while FANET is a community network specific to free flight. Both can coexist on the same device without one replacing the other.