###### Abstract
It was unveiled as Broadcom's inaugural dual-frequency GNSS chipset in San Jose, California. This chipset heralded a new era of enhanced communication between smartphones and conventional GNSS receivers, offering advantages to users and developers alike. Introduced in May 2018, the BCM47755 chipset made its debut through Xiaomi, a prominent company in the smartphone industry. This strategic collaboration introduced a cutting-edge component that revolutionized location-based services on smartphones. By leveraging the capabilities of the dual-frequency GNSS chipset, Xiaomi smartphones could establish more robust and accurate connections with satellite-based positioning systems. Specifically, the BCM47755 chipset was designed to work seamlessly with L1/E1 and L5/E5 frequencies. This dual-frequency feature improved the accuracy of the location data and mitigated the impact of signal disruptions and inaccuracies caused by atmospheric conditions and signal reflections. In subsequent developments, researchers advancing GNSS receiver techniques for Android smartphones made significant progress. Among these advancements, [PERSON] [15] and his team explored and implemented techniques such as RTK positioning and PPP on the Xiaomi Mis smartphone. Using RTK and PPP techniques, the dynamic positioning of the Xiaomi Mis was achieved, with impressive results. The horizontal root mean squares (RMSs), a key metric for assessing positioning accuracy, were reported as 1.17 m and 2.23 m for the RTK and PPP techniques, respectively. This demonstrated the chipset's ability to deliver highly accurate and reliable positioning information, significantly outperforming conventional single-frequency GNSS solutions. The successful application of advanced GNSS receiver techniques showcased the capabilities of the BCM47755 chipset and demonstrated the potential for significantly enhancing smartphone-based positioning methods. With improved accuracy and reduced errors, these advancements hold great potential for many applications, from navigation and positioning to augmented reality and location-based services. Previously, studies [5; 6; 8; 19; 20] used pseudorange differential corrections in the position domain using a measurement matrix, enabling meter-level positioning regardless of raw smartphone data. As a result of subsequent studies, greater precision has been achieved regarding positioning. As a result of leveraging dual-frequency raw observations derived from smartphones, a PPP model without the ionosphere was presented in [5]. The model utilized dual-frequency raw observations from smartphones to achieve sub-meter-level positioning under static open-sky conditions following convergence. Multipath effects have been demonstrated in a number of studies [5; 21]. In their study [6], [PERSON] et al. showed that it was possible to mitigate the multipath susceptibility of the built-in antennae of smartphones and achieve accurate positioning to the centimeter level by using an attached external auxiliary antenna. According to a recent research study [20; 21], using smartphone antennae and a Kalman filter to link the temporal parameters (the multi-epoch model) to the internal antennae has achieved centimeter-level positioning accuracy. Carrier-phase drift in smartphone observation data has recently been confirmed by [22; 23]. The phase offsets and drifts observed in this study are similar to those observed in previous studies (e.g., [5; 6; 8; 13; 24; 25]). It has been demonstrated that MEMS (Micro-Electro Mechanical System)-IMUs (Inertial Measurement Units) are affordable and capable of achieving accuracy levels within the decimeter range in 60 s when combined with high-precision GNSS receivers operating in the PPP mode during interruptions of the GNSS signals [26]. Combined with low-cost, single-frequency GNSS receivers, these devices can provide accuracy at the meter level [27].