Broadcom’s second-generation dual-frequency GNSS uses new L5 signals

BCM4776 chip utilizes 30 new L5 signals to deliver higher navigational accuracy and yield

Photo: Broadcom

Broadcom introduced in 2017 the first mass-market implementation of dual frequency: BCM4775. This chip makes use not only of the classic L1 frequency broadcast by every satellite, but also of the more advanced L5 signal broadcast by a subset of the satellites.

The use of this enhanced L5 signal improves the accuracy of GNSS in an urban scenario, as it mitigates the main source of error: the reflections in the nearby buildings, also known as multipath. It also improves GNSS in an open-sky scenario, allowing submeter accuracy, a previously unmet performance bar in smartphones until now. Ever since, the BCM4775 has been adopted in flagship smartphones, smartwatches and fitness devices.

Given the unabated need for better precision and accuracy, Broadcom has introduced its second-generation dual-frequency GNSS solution — the BCM4776.

The new chip is capable of using the new BeiDou-3 constellation’s B2a signals (the Chinese indicator for L5). It will be able to track 30 new L5 signals (60 percent more) with a significant impact on accuracy. End users will experience much higher reliability of the submeter accuracy inherent to dual-frequency L1-L5.

Image: Broadcom

Second generation dual-frequency GNSS will be used for innovative lane-level driving navigation instructions, allowing driving applications to know which highway lane the vehicle is in. Expect instructions like “move one lane to the right so you don’t miss your next highway exit” or “move one lane to the left to take the pool lane and save 10 minutes.”

The BCM4776 is now in production.