This disclosure provides systems and methods for determining a location of a mobile device within an indoor environment. An embodiment of the system can have one or more positioning nodes (PONs), each having one or more antennas. Each PON can be disposed at a location within indoor environment and configured to transmit signals via the one or more antennas. The signals transmitted from the antennas of the PONs can be synchronized in time and frequency. A server communicatively coupled to the PONs and storing aiding information, including location and signal information related to the PONs, can transmit the aiding information to a mobile device. The mobile device can receive the signals from use the PONs and use the aiding information to determine a three dimensional position within the indoor environment based on one-way time difference of arrival of the signals.