Trusted Portable Navigator (T-PN) provides a real-time, continuous and reliable positioning and localization solution for indoor or outdoor smartphone usage. The T-PN software development kit (SDK) is a highly modularized and flexible SDK that can easily be configured to fit a variety of mobile and portable devices. The T-PN was tested on MOTOROLA Xoom Wi-Fi MZ604 running Android 3.2, SAMSUNG Galaxy Nexus GT-I9250 running Android 4.0, Blackberry 16GB Playbook QNX 220.127.116.118, the SAMSUNG Galaxy Note GT-N7000 which is running Android 2.3, and the SAMSUNG SIII running Android 4.0.4. The T-PN makes use of Micro-Electro Mechanical Sensors (MEMS) inertial sensors that are already a part of smartphones to enable entertainment and provide convenience to the user. These same sensors when used by T-PN provide 3-D positioning to the user when satellite signals are degraded or absent in urban canyons or in deep indoor environments. The solution also provides the heading of the user, the 3D orientation of the device, and the user's velocity, all without imposing any restriction on the usage of the device. The T-PN solution provides accuracy measures in addition to the position, velocity, and attitude solution to satisfy the high demands of Location Based Services (LBS).