Abstract:
The present invention relates to a time division multiple access (TDMA) frame structure for avoiding the probability of a collision between nodes on an ad-hoc network and a method for assigning a dynamic time slot to a node using the same. The TDMA frame structure according to the present invention comprises a plurality of repeated subframes which comprise a signaling period composed of control signals for data transmission and a data period for transmitting data, wherein the signaling period comprises: a request mini slot whereby a transmission node to transmit data requests slot allocation; an information mini slot for delivering slot information used by a node in a corresponding subframe and slot information on a 1-hop neighbor node; a suggestion mini slot for suggesting, to a neighbor node, a time slot to be allocated to the transmission node by using the information collected from the information mini slot; and a reply mini slot for replying to time slot allocation suggested by the transmission node in the suggestion mini slot.
Abstract:
The present invention relates to a new method for compensating a position error by adjusting transmission intervals of navigation signals from reference stations, which calculates an accurate position of a receiver using navigation signals transmitted from a plurality of reference terminals without using a separate position compensating system at a receiving terminal. In order to accomplish this, disclosed is a method for compensating a position error by adjusting transmission intervals of navigation signals from reference stations comprising: a receiving step which periodically receives navigation signals from at least four reference terminals, wherein positions of the reference terminals on earth are known; a synchronizing step which performs a synchronous control for periodically synchronizing time among reference terminals; an error calculating step during which the respective reference terminals compare a position calculation value using the navigation signal received during the receiving step with an actual coordinate values to calculate a position error; a transmitting step which generates a navigation signal for calculating the position of the receiving terminal by reflecting the position error calculated in the error calculating step and retransmits the navigation signal; and a position calculating step which receives the navigation signal transmitted during the transmitting step and calculates a position.
Abstract:
본 발명은 수신단말에서 별도의 위치보정시스템을 구비하지 않고, 다수의 기준국에서 송신된 항법신호를 통해 수신자의 정확한 위치를 계산하도록 하는 새로운 기준국간 항법신호 송신간격 조정을 통한 위치오차 보정방법에 관한 것이다. 이를 위해, 지구상의 자신의 위치를 알고 있는 적어도 4개의 기준국으로부터 주기적으로 항법신호를 수신하는 수신단계와, 상기 기준국간에 주기적으로 시각 동기화를 위한 동기제어를 수행하는 동기단계, 각 기준국은 상기 수신단계에서 수신한 항법신호를 이용한 위치계산값과 실제 좌표를 비교하여 위치오차를 계산하는 오차계산단계, 상기 오차계산단계에서 계산된 위치오차를 반영하여 수신단말의 위치계산을 위한 항법신호를 재전송하는 전송단계, 그리고 상기 전송단계에서 전송된 항법신호를 수신하여 위치를 계산하는 위치계산단계를 포함하는 기준국간 항법신호 송신간격 조정을 통한 위치오차 보정방법이 개시된다.