How Accurate Is Phone Gps?

How Accurate Is Phone Gps? For example, GPS-enabled smartphones are typically accurate to within a 4.9 m (16 ft.) radius under open sky (view source at ION.org). However, their accuracy worsens near buildings, bridges, and trees. High-end users boost GPS accuracy with dual-frequency receivers and/or augmentation systems. Do cell phones have true GPS? GPS Tracking