The GPS Signal

Although initially designed for the United States military, the Global Positioning System or GPS now plays a vital role in our lives. From turn-by-turn navigation to sharing our location for grocery delivery, we use GPS on a daily basis. But for the longest time, your smartphone, in-car navigation, or smartwatch would use a legacy frequency called L1 to get the GPS signal and determine its location.

L1 is widely used, and it has helped transform the world in a big way. But this frequency is susceptible to multipath errors, which are caused when some GPS signals are reflected by buildings, the ground, and other objects before reaching the receiver. Determining locations in GPS is based on measuring distances to the satellites, so these reflections cause a problem, showing a different distance than a signal that reaches the receiver directly from the satellite. The L1 signals are also not very effective at traveling through physical obstructions.

So, the US government has been running a GPS modernization program to keep up with the changing times and advancing technology. As a part of this modernization effort, it’s fielding three new GPS signals for civilian use: L2, L5, and L1C.

L1C is still in a developmental stage and doesn’t provide navigation data, but the L2 and L5 signals are in different pre-operational stages, with more satellites transmitting the L2 signal than the L5 as of June 2022. The US government aims to enhance GPS location accuracy for civilian usage with these new signals.

While both L2 and L5 signals are more powerful than the L1 signal and have more bandwidth, the L5 is the best of the three at pretty much everything, including dealing with interference and multipath errors. Also, L2 is supposed to be used with the L1 signal to boost its accuracy; the L5 signal can be interpreted independently.

L5 started broadcasting on supported satellites in 2014, and as of June 2022, it’s transmitted by 17 GPS satellites. As any GPS signal broadcast by less than 18-24 satellites is considered of limited use, L5 will take at least one more satellite launch to become reasonably helpful. 24 L5 capable satellites are expected to reach the skies by 2027.

Why Does L5 Matter?

As mentioned, L5 is the most advanced GPS signal available for civilian use. Although it’s primarily meant for life-critical and high-performance applications, such as helping aircraft navigate, it’s available for everyone, like the L1 signal. So the manufacturers of mass-market consumer devices such as smartphones, fitness trackers, in-car navigation systems, and smartwatches are integrating it into their devices to offer the best possible GPS experience.

One of the key advantages that the L5 signal possesses is that it uses the 1176.45MHz radio frequency, which is reserved for aeronautical navigation worldwide. As such, it doesn’t have to worry about interference from any other radio wave traffic in this frequency, such as television broadcasts, radars, and any ground-based navigation aids.

With L5 data, your device can access more advanced methods to determine which signals have less error and effectively pinpoint the location. It’s particularly helpful at areas where GPS signal can be received but is severely degraded. In such situations, L5, thanks to its increased bandwidth, can supply more information beneficial in determining reflections present in the received signal.

Additionally, the stronger L5 signal results in better coverage in dense urban environments and helps devices get a location lock quickly. Finally, its lower frequency enhances reception for indoor use.

So, you can expect devices capable of receiving the L5 signal to provide more accurate location data than devices with the L1 or L2 signals.

Which Devices Use the L5 Signal?

Device manufacturers have started using the L5 signal as a part of the dual-frequency GPS alongside the L1 signal. The Xiaomi Mi 8 was the first smartphone to get L5 support in 2018, but since then, multiple devices with the same feature have landed on the market. Some of the popular devices that we know are capable of receiving the L5 GPS signal include the Apple Watch Ultra, Garmin’s GPSMAP 65, 65s, and 66sr handheld GPS trackers, Google Pixel 4, 5, and 6-series phones, and Samsung’s Galaxy S22+, S21+, and S21 Ultra phones.

Unfortunately, getting one list with all devices capable of receiving the L5 GPS signal is impossible. But this open database on Google Sheets, containing information from the GPSTest Android app, seems to include most Android phones that support the L5 signal.

Plus, if you are curious whether your Android phone supports it or not, Huawei recommends using the GNSSLogger by Google. You can use the app to capture the global navigation satellite system (GNSS) data and determine L5 signal presence. The GPSTest app mentioned earlier is also often recommended as one of the options to check whether an Android device supports L5.

Another option is reaching out to the device manufacturer to find out whether a particular device supports the L5 signal.

Remember, the L5 signal require new hardware and won’t work on older devices that are only compatible with the L1 signal.

L5 Signals Aren’t Limited to GPS

GPS, which is owned by the US government, isn’t the only global navigation satellite system (GNSS). It isn’t the only GNNS to use the L5 signal, either. China’s BeiDou, the EU’s Galileo, India’s IRNSS, and Japan’s QZSS also transmit signals in the L5 frequency. Plus, Russia’s Glonass plans to launch satellites capable of broadcasting the L5 signal by 2025.

L5 signals from these satellite systems can be used by many GPS receivers employed by consumer-grade devices. These multi-GNSS receivers can offer even better location accuracy than those that only use GPS.

Improved Location Accuracy

The L5 signal is a welcome addition to the GPS arsenal. It can significantly enhance the location accuracy on your devices, make getting a location lock faster, and even work better at places the legacy L1 band typically struggles. That said, at the time of writing the US government is yet to put enough satellites to make the L5 signal officially operational, so it’ll take at least a couple of years for us to reap all of its benefits.

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