An indoor positioning method includes scanning for registered Wi-Fi nodes with known coordinates to generate a list of the registered Wi-Fi nodes. The method also includes performing a ranging operation by (i) selecting nodes to range with from the list of the registered Wi-Fi nodes, and (ii) processing ranging responses from the selected nodes to generate a series of distance measurements. The method further includes obtaining a series of sensor readings generated by one or more inertial measurement units (IMUs) of a device. The method also includes estimating a position of the device based on the series of distance measurements and the series of sensor readings using first and second filtering operations that are performed in parallel.