Patent ID: 7843379

Claim:
Method for determining the spatial distance between two transmitter-receivers within a distance range in the order of magnitude of 10 km, in which both transmitter-receivers set off respectively at least one signal round, a signal round comprising the following steps: transmitting at least one request data frame, containing a sequence of at least two signal pulses with a predetermined pulse time interval, from a first transmitter-receiver setting off the signal round to a second transmitter-receiver at a request transmitting time (T TA1 , T TB2 ), receiving the request data frame at the second transmitter-receiver at a request receiving time (T RB1 , T RA2 ), transmitting a reply data frame, containing a sequence of at least two signal pulses with a predetermined pulse time interval, from the second transmitter-receiver to the first transmitter-receiver at a reply transmitting time (T TB1 , T TA2 ), which has a respective reply time interval (T replyB1 , T replyA2 ) from the request receiving time (T RB1 , T RA2 ), and detecting the respective reply time interval, receiving the reply data frame at the first transmitter-receiver setting off the signal round and detecting a reply receiving time (T RA1 , T RB2 ), allocated to the receipt of the reply data frame, relative to the request transmitting time (T TA1 , T TB2 ), at which an evaluation is carried out comprising the following steps: ascertaining a round time interval (T roundA1 , T roundB2 ) between the respective request transmitting time (T TA1 , T TB2 ) and the respective reply receiving time (T RA1 , T RB2 ) for each signal round, this step being able to be performed at any time after the relevant signal round, ascertaining a signal transit time (T prop ) between the two transmitter-receivers using the ascertained round time intervals (T roundA1 , T roundB2 ) and the reply time intervals (T replyB1 , T replyA2 ) and ascertaining the spatial distance between the first and second transmitter-receivers by multiplying the signal transit time (T prop ) (by a previously known propagation speed of the signal pulses, and in which the signal rounds are performed in such a way that the reply time intervals (T replyA2 , T replyB1 ) are either identical or have a difference, in the case of performing more than one signal round set off by each transmitter-receiver an average difference, the amount of which is a maximum of 200 microseconds.