The present invention provides a Positioning on One Device (POD) for locating and tracking objects and an autonomous ultrasound indoor track system (AUITS) and method for locating objects by using the POD. The AUITS can comprise: a tag device installed on a mobile object, which includes radio frequency (RF) and ultrasound transmitters for transmitting RF and ultrasound signals; and a POD for receiving the RF and ultrasound signals transmitted from the tag device to locate the mobile object. The POD can comprise: a plurality of leaf modules, each of the leaf modules including a positioning signal receiver for receiving the positioning signals (e.g. ultrasound signal) transmitted from the tag device, wherein there is a known structural topology relationship between the plurality of leaf modules. Then, the positioning signal detection times from respective positioning signal receivers and the structural topology relationship of the POD can be used for calculation of the position of the object. Compared with the prior arts, the POD and the AUITS system of the present invention presents several advantages, such as high accuracy, easy deployment, calibration free, low cost, in-device coordination, and flexibility.