Car navigation system often appears in writings on relativity. But Orbis (for speed check) seems not to be referred. May be relativity can't show the constancy of light speed (with that formula, light speed = wave length x frequency) about Orbis.

On the comparison between incident wave and reflecting wave at the inertial frame of the car (it's moving), frequency is equal always. Then, if light speed of the two waves is equal, wave length (wave number) of the two waves is equal also. Therefore, if the light speed of emitted wave and incident wave is equal at the inertial frame of Orbis, frequency of the two waves may be equal (Doppler effect doesn't occur).

Note : This item is founded on the phenomena of inertial frame of Orbis and the car. So, there is no need to pay attention to time dilation or length contraction.

In a web site, the formula of Orbis is shown. There are terms (c+V),(c-V) in it. Really?? If it's real, that phoenix !!

About emitted beam and reflected beam of "Orbis" or "speed gun", the formula : lightspeed = frequency x wavelength is as follows. At observer (at stand-still in the air) : Lightspeed is equal. Frequency & wavelength is not equal. At moving object : Frequency is equal. Lightspeed & wavelength is not equal.

In the outer space, lightspeed is not equal at both (observer and moving object).