When Apple launched the Watch Ultra last year, it entered a category intended for those who are fitness nerds. The Watch Ultra has a variety of features suitable for users interested in hiking, marathons, swimming and other fitness activities. One of the main things Apple improved with the Watch Ultra is how it uses its GPS-enabled features. Earlier Apple Watch models relied on a frequency band that was L1. However, the Watch Ultra uses the L1 and L5 radio frequencies to deliver better results, which is extremely helpful for users. Here we explain how it works on the Apple Watch Ultra:
What are the L1 and L5 frequency bands?
The L1 frequency is the main frequency used in GPS. It operates at a frequency of 1575.42 MHz and has a wavelength of about 19 centimeters. The L1 frequency is commonly used for navigation and even surveying.
The L5 frequency, on the other hand, is a newer frequency that operates at a frequency of 1176.45 MHz and has a wavelength of about 25 centimeters. The L5 frequency is primarily used for civilian purposes, including security applications such as aviation, shipping, and ground transportation.
How do dual band antennas work?
A dual-band antenna is used to receive signals on two different frequencies. In the context of GPS, a dual band antenna is designed to receive both the L1 and L5 frequencies. This type of antenna is commonly referred to as an L1/L5 dual band antenna. It’s this antenna that Apple used in the Watch Ultra.
On the Watch Ultra, Apple has delivered more accurate and reliable GPS positioning by using an L1/L5 dual-band antenna. It combines data from these two frequencies to provide accurate distance, pace and route calculations
One of the main reasons for this is the L5 frequency, which is less prone to interference and multipath errors compared to the L1 frequency.
What features of the Apple Watch Ultra rely on GPS?
Features like backtrack and waypoints found in the Watch Ultra rely heavily on the GPS sensors. Apple says a traditional GPS solution with just L1 GPS works well most of the time. But it can be difficult when tall buildings, trees, or dense foliage are blocking satellites. The newer L5 GPS enables advanced signal processing, reducing many errors and providing a more consistent signal in environments like densely populated cities. So it can be useful when traveling in areas with tall buildings and help with navigation. Multipath errors occur when GPS signals bounce off of nearby objects, causing the receiver to receive multiple signals that can cause errors in position calculations. By using both frequencies, an L1/L5 dual band antenna can help reduce the effects of multipath errors and improve GPS positioning accuracy. Because of this, GPS tracking on the Apple Watch Ultra is much better in both urban areas and outdoor hiking trails.
Apple also ensures the dual-frequency system will combine with Apple Maps to include road, bike and walking routes that better identify actual locations. Accuracy is increased with new satellite and signal models. In addition, Apple uses a custom, advanced algorithm that makes the best use of available satellite signals.
L1 and L5 Dual Band Antennas: More details
An L1/L5 dual band antenna works by receiving GPS signals from the L1 and L5 frequencies. The antenna is designed to receive both frequencies simultaneously and then transmit them to the GPS receiver for processing. The GPS receiver then uses the information received from both frequencies to calculate a more accurate position.
To receive signals on both frequencies, the antenna is designed to have two separate elements, one for each frequency. These elements are usually arranged in such a way that they can receive both frequencies without interfering with each other. The antenna is also equipped with a low-noise amplifier (LNA) that amplifies the received signals before sending them to the GPS receiver.