[TexasTransplant]

>>>"The pulsing nanotubes reflect light waves like a car reflects the sound waves from a police radar gun. As the radar gun measures a car's speed by the frequency of the sound waves it reflects,"<<<

This author has SONAR and RADAR confused, RADAR would be RF Energy transmitted and reflected back to the Transmitter and the resultant round trip time would be used to determine distance this distance measured numerous times from which a closing speed can be calculated (Relative Speed to the Transmitter), with Sonar you can perform a very similar calculation but the medium that the sound is traveling in must be identified measured and taken into consideration since the properties of sound are affected by things such as density, temperature, pressure and the properties of the sound that is transmitted itself (frequency, amplitude etc)

Sonar would make a very inefficient instrument to measure an automobiles speed.

TT

[TexasTransplant]

>>>" Sonar would make a very inefficient instrument to measure an automobiles speed"<<<

Active SONAR would be very inefficient, however Passive SONAR could be used as a Stationary Recorder, as an auto approaches the Sonar could measure a certain sound frequency as it approaches and then passes comparing the difference in up and down Doppler and get a fairly accurate speed.

[MindBender26]

Actually,police speed radar does not use distance measuring but uses Doppler frequency shift.

The laser guns use distance change rate, but the radar guns do not.