## 1 Introduction  
Precise Point Positioning (PPP) and Real-Time Kinematic (RTK) are now the most widely utilized high-precision Global Navigation Satellite System (GNSS) positioning techniques. RTK approach relies on reference stations, referred to as base stations, in conjunction with robust communication networks, while the PPP technique utilizes a single GNSS receiver [1, 2]. On the other hand, a significant limitation of the PPP approach is its prolonged convergence time, which presents a challenge for real-time applications [3]. With the accelerated advancements in GNSS technology, the current constellations comprise over 100 GNSS satellites, including GPS, GLONASS, Galileo, and BeiDou satellite systems [4]. The integration of these multi-GNSS satellites significantly contributes to reducing convergence time, and it enables users to achieve centimeter-level accuracy within ten minutes of convergence time [5,6]. Furthermore, it aids in enhancing the GNSS raw data from low-cost receivers, which are often prone to data losses [7]. To achieve a high level of accuracy, PPP depends on the International GNSS Service (IGS), which provides a variety of products to mitigate GNSS-based errors. These products include GNSS satellite ephemerides, Earth rotation parameters, satellite clock corrections, zenith tropospheric path delay estimates, and Global Ionosphere Maps (GIM). Moreover, they are available from various Analysis Centers (ACs), such as the Center for Orbit Determination in Europe (CODE), the European Space Operations Center (ESA), the GeoForschungsZentrum (GFZ), Le Groupe de Recherche de Geodesie Spatiale (GRG), Wuhan University (WUM) [8, 9, 10], and the Centre National d'Etudes Spatiales (CNES), archived real-time products [11]. Since ionospheric delay is a crucial issue for single-frequency PPP users, they have to utilize the Klobuchar, NeQuick, or IGS-GIM models [12, 13, 14] to account for the ionospheric error. Dual-frequency users can take advantage of the ionospheric dispersive nature by employing the Ionosphere-Free Precise Point Positioning (IF-PPP) method, which effectively mitigates approximately 99% of the ionospheric delay [15]. Furthermore, the undifferenced Uncombined Precise Point Positioning (UPPP) method that estimates the ionospheric delay as an unknown parameter can enhance both positional accuracy and convergence time [16]. At present, significant breakthroughs in affordable smartphone-based GNSS precise positioning are fulfilled with the launch of the Xiaomi Mi8, which is equipped with the Broadcom BCM4775 chipset because it supports multi-frequency and multi-GNSS systems [17]. Also, it demonstrated Root Mean Square Error (RMSE) of 4.14 m in horizontal, when utilizing single-frequency multi-GNSS data in conjunction with Single Point Positioning (SPP) approach [18]. Moreover, the results showed that decimeter- and meter-level horizontal positioning accuracy can be attained in static and kinematic modes, respectively, using the PPP technique [19]. Following the launch of the Mi8, several smartphone modules are released, such as Huawei Mate 40 and P40, Samsung Galaxy S20, and Google Pixel 4 [20, 21, 22], which pave the way for low-cost and highly precise GNSS positioning applications. Unlike the geodetic receiver, the carrier-to-noise ratio (C/N0) for the smartphone is low [23]; as a result, the observed datasets are lost, and then the positioning accuracy is degraded. For this reason, a number of researchers suggest applying the weighting model based on the C/N0 rather than the model based on the elevation angle for stochastic model estimation [24, 25, 26]. In this research, the real-time and post-processing GNSS positioning performance of the Xiaomi 11T module for static applications is evaluated. This Xiaomi 11T module has many GNSS features, such as supporting multi-frequency multi-constellation GNSS (i.e., GPS L\({}_{1}\)/L\({}_{5}\), Galileo E\({}_{1}\)/E\({}_{5a}\), GLONASS G\({}_{1}\), and BeiDou B\({}_{1}\)[27].