For generating a delay signal, a series of source signals based on the same high frequency signal are first provided. The snow plow includes a hitch frame nose assembly configured to couple to a vehicle by securing each of a chassis coupler to the vehicle chassis. The second optical signal and the third optical signal counterpropagate through the Bragg fiber and return to the third port and the second port, respectively. From the results of the analyses, the mass of the soluble contaminant removed from the sediment over time can be calculated. The computing device queries the map for visibility information for the first feature at a first position. A perpendicular line to the virtual reference face at any position of the image formation face passes through an outside of the reflection face of the optical device.