the angular covering requirement furthermore collision with permitted maximum radiation in these other bands may occur at f o 2 45 ghz a resolution of 1 hz is required to indicate 6 cm s which gives a measuring time of at least 1 second when 50 objects are to be monitored it will take at least 50 seconds between the observations of an object the object can have moved 3 m at 6 cm s or 140 m at 10 km h in this space of time if lower requirements are placed on the speed resolution both measuring time and time intervals can be reduced the smallest detectable movement will still be 3 m although the value at 10 km h will decrease proportionally in order to lower the bottom limit of detectable movement it is necessary either to increase f o or to reduce the number of monitored objects the position of the monitored object must be calculated by numerical integration of the speed determinations this quickly gives rise to large positional errors particularly when monitoring vessels that are moored in a harbour due to the reciprocatory motion that occurs furthermore only movement towards or away from the base station is indicated not sideways movement in order to avoid false alarms or non occurrent alarms it will.