Explaining the Different Types of GPS Signals: L2C & L5

How is GPS Changing?

Global Positioning System – or GPS – is the United States’ Global Navigation Satellite System, the world’s most utilised GNSS, allowing anyone with a receiver to calculate their exact position on Earth using an orbiting constellation of satellites.

L1 C/A remains the leading GPS signal and is used in almost all GPS devices and technology. But the United States has vowed to modernise the entire system one satellite launch at a time, equipping them with new hardware to take advantage of new specialised technology. This includes the introduction of both L2C and L5 signal specifications, set to revolutionise their respective fields, although neither are fully operational quite yet. Although L1 C/A is an older signal, it’s still of paramount importance to GPS and will work in tandem with the new signals as part of a stronger multi-band positioning system rather than being simply replaced.

L2C: The Next Level of Accuracy and Speed

L2C is a new civilian-use signal broadcast on the L2 band at a frequency of 1227.60 MHz, which enables greater speed than L1. There are two military signals on the L2 frequency but the technology using the band has been specifically designed for commercial needs. With the use of dual-frequency receivers, civilians can now enjoy the same level of accuracy as military applications.

The L2C signal not only acts as a redundant signal in case of localised interference but its core purpose is to improve accuracy of navigation and offer a signal that is very easy to track. However, it has to be used alongside L1 frequencies and cannot operate alone. When combined as a multi-band signal, L2 and L1 can better travel through objects, whether its buildings, trees, or clouds, and has greater operating range, accuracy, reliability, and faster signal acquisition.

L2C is still considered pre-operational despite beginning to broadcast in April 2014. The issue is that it requires new hardware onboard satellites and therefore is reliant on new launches to replace the existing constellation. As of July 2023, 25 satellites are capable of broadcasting L2C.

L5: Robust Safety for Air Travel

L5 is broadcast, unsurprisingly, on the L5 band at a frequency of 1176.45 MHz. This is specifically an aeronautical navigation band and L5 is considered a Safety-of-Life (SoL) data signal. The frequency was specifically chosen because the aviation industry can manage interference much more effectively on L5 than L2, and the frequency band is internationally protected by the International Telecommunication Union (ITU) for aeronautical radionavigation services.

In an exciting development, aircraft can now use a combination of L5 and L1 C/A. Together they provide a GPS signal robust enough for life critical applications, such as precision approach guidance for aircraft, and can improve accuracy via ionospheric correction. GTT Wireless is proud to be at the forefront of this technological advancement with our new antenna which utilises both L1 and L5 bands. L5 is transmitted at a higher power level than other GPS signals and reception is enhanced because of its lower frequency and wider bandwidth.

As with L2C signals, L5 began broadcasting on satellites that could support it in April 2014. The L5 satellite constellation has been fast growing in recent years, and is now seen as the dominant unified-signal structure in GNSS.

GTT Wireless’s commitment to GPS

GTT Wireless vow to be at the forefront of advancements in GPS technology and stock a range of GPS/GNSS outdoor antenna that can be used for a variety of Internet of Things (IoT) applications. Our antenna’s robust IP67/NEMA6 waterproof and UV-resistant design allow them to perform consistently, even in extreme environments. You can visit our antenna store or build a weatherproof outdoor electronics enclosure for your mission critical project using our enclosure configurator.