1.   Atomic clocks calculate the passage of time by measuring the vibration of cesium atoms, which are accurate to within a few billionths of a second per day.

2.   A Global Positioning System accurate within a meter will be fixed on the front and rear of the barge to help the crew keep it precisely over the Kursk.

3.   A new type of atomic clock has the potential to do far better, to be accurate to within a second every few billion years.

4.   But now, a new type of atomic clock has the potential to do far better, to be accurate to within a second every few billion years.

5.   Data are updated four times a second, and the system is accurate to within half a meter.

6.   Distances at the foul lines also proved to be accurate within a few inches.

7.   Dilz said the device was accurate to within one mile per hour, compared with the more industrial strength radar guns.

8.   Still, Ingram said, the tapes were accurate to within only a tenth of a foot.

9.   The current system of radio-based navigation is accurate to within about one mile.

10.   The missiles are said to be accurate to within a few dozen feet.