Transmitting Time and Frequency Data by Using Broadcast TV Signals Observed in Common-View

We will study the possibility of transmitting time and frequency data by using broadcast TV signals observed in common-view, in which two sites receive the transmissions from a single transmitter. The statistical characteristics of the path delay will make an important contribution to the error budget of the method, so that an evaluation of the path delay is an important first step in deciding whether to implement it. The variation in the path delay will be evaluated by receiving the signal at two sites and where the times of the clocks at both sites are known from other, independent methods. The advantages of the common-view method will be discussed; the method does not require any modifications to the transmitting equipment and is independent of the accuracy and stability of the transmitter time and frequency reference. In addition, the method cancels or attenuates the contribution of the path delay that is common to the paths to the two receiving stations that will participate in the test. The uncertainty in the coordinates of the transmitter and the receiving stations would be important in limiting the accuracy of a time service based on these transmissions, but the actual locations introduce only a constant bias into the delay and are not important for an evaluation of the stability of the method.

Judah Levine | Time and Frequency Division, National Institute of Standards and Technology | Boulder, Colorado, United States
Christine Hackman | Advanced Space PNT Branch, Naval Research Laboratory | Washington D.C., United States