The ultra-wideband (UWB)-based positioning has a wide internet of things applications such as smart medical and smart logistics, due to its high positioning accuracy. However, non-line-of-sight radio propagation degrades UWB positioning accuracy. The inertial measurement unit (IMU) can achieve positioning with high accuracy in a short time. In addition, the millimeter wave (mmWave) radar can work well in scenes such as fog, smoke, dust, and other small particles due to the longer wavelength of mmWave Radar, but the drift error of IMU and mmWave radar are all increased rapidly over time. This paper achieves the tight coupling of UWB and IMU, UWB and mmWave radar based on the extended Kalman filter, respectively. The field experiments were conducted based on a handheld platform in an indoor scene to evaluate and compare the performance of the fusion position systems; the experiment results demonstrated that the positioning accuracy by fusing UWB/IMU and UWB/mmWave was significantly higher than that of the positioning using a single sensor.