Patent ID: 7710829
Filing Date: 2010-05-04
Classification: G01S

Abstract:
1. A hybrid ranging method comprising the steps of: transmitting from a first node an ultrasonic signal and a radio signal comprising at least one radio synchronization signal with a predetermined ratio therebetween; calculating, at a second node, a ultrasonic transmission time period between the receipt of the radio synchronization signal and the receipt of the ultrasonic signal; calculating, at the second node, an ultrasonic measured result between the first node and the second node by using the ultrasonic transmission time period; calculating, at the second node, the strength of the received radio signal, and obtaining a radio measured result between the first node and the second node from a reference database; calculating, at the second node, the smoothness of the ultrasonic measured result and the radio measured result; and determining, at the second node, a final measured result according to the smoothness of the ultrasonic measured result and the radio measured result.