A positioning unit and telecommunications unit wherein a reference time value from is requested from a telecommunications network to start the positioning receiver. A strobe is scheduled to be transmitted from the telecommunications unit to the positioning receiver when the positioning receiver is armed. A current and predefined value of the counter is compared and the strobe is generated when the counter current value equals the predefined value. The strobe time of generation is recorded in relation to a structure of the signal transmitted by the digital telecommunications network in the current serving cell. The reference time value from the telecommunications network is received, wherein the reference time value is related to a structure of the signal transmitted by the network. The accurate time of generation of the strobe based on said reference time value is calculated transmitted to said positioning unit.