A hybrid TDOA-TOA positioning system can be implemented to improve location estimation of a wireless network device. An initial location of the wireless network device can be calculated based on locations of a plurality of reference network devices. An intermediate location of the wireless network device can be determined based, at least in part, on the initial location of the wireless network device and distance differences between the wireless network device and each pair of the reference network devices. A second intermediate location of the wireless network device and a distance calibration constant can be calculated based on the locations of the reference network devices, the intermediate location, and/or round trip transit times between the wireless network device and each reference network device. The location of the wireless network device can be iteratively estimated based, at least in part, on the second intermediate location and the distance calibration constant.