by CopRadar on Tue Aug 15, 2006 8:30 pm
Lidars (depending on model) must receive (and transmit) tens to several hundreds of pulses to make ONE speed measurement. A few stray pulses will make little if any difference.
Two lidars operating next to each other trying to measure targets in different traffic lanes at the same time could (but not always) produce a false speed reading. The circumstances to predict a false speed reading involve a number of variables, not all variables are known and some change with situation (such as exact time each lidar transmits, sample start/stop periods, range of targets, etc.).
Two lidars should not be operating next to each due to the uncertainty of the accuracy and reliability of any speed measurements.
Lidar beam coverage depends on beamwidth and target range. Most lidars have a beamwidth between 3 and 4 milliradians (0.17 to 0.23 degrees). A 16 inch beam spread would occur at a range of 444 feet for a 3 mR beam and 333 feet for a 4 mR beam.
Yes is is possible for a lidar (or microwave radar) to measure the speed of a larger vehicle behind (more distant from lidar) than a closer smaller vehicle.
Lidars (depending on model) must receive (and transmit) tens to several hundreds of pulses to make ONE speed measurement. A few stray pulses will make little if any difference.
Two lidars operating next to each other trying to measure targets in different traffic lanes at the same time could (but not always) produce a false speed reading. The circumstances to predict a false speed reading involve a number of variables, not all variables are known and some change with situation (such as exact time each lidar transmits, sample start/stop periods, range of targets, etc.).
Two lidars should not be operating next to each due to the uncertainty of the accuracy and reliability of any speed measurements.
Lidar beam coverage depends on beamwidth and target range. Most lidars have a beamwidth between 3 and 4 milliradians (0.17 to 0.23 degrees). A 16 inch beam spread would occur at a range of 444 feet for a 3 mR beam and 333 feet for a 4 mR beam.
Yes is is possible for a lidar (or microwave radar) to measure the speed of a larger vehicle behind (more distant from lidar) than a closer smaller vehicle.