Abstract: A light weight, bi-directional, computerized profilograph is disclosed. The bi-directional profilograph includes an odometer for measuring the horizontal movement of the profilograph in either a first direction or a second direction, and a road surface measuring device for measuring a road surface profile while the profilograph is traveling in either the first direction or the second direction. A computation device is also included for plotting the profile of the road surface versus the horizontal movement of the profilograph while the profilograph is traveling in either the first direction or the second direction.

Abstract: Apparatus that detects the presence and condition of precipitation on the surface of a pathway. The apparatus has a block of electrically insulative material adapted to be embedded in the pathway with a top surface exposed to precipitation. A sensor is embedded in the block for sensing a physical property of the precipitation to produce a sensor output which is also influenced by a depth of the precipitation. Part of the top surface of the block has a well that is generally curved in outline above the sensor for gathering precipitation for the sensor. Advantageously, the influence of precipitation depth on the sensor is diminished. Other apparatus and methods are also disclosed.

Abstract: Apparatus for determining or measuring the depth of precipitation accumulating on the surface of a pathway, such as an airport runway or the like. The apparatus includes a sensor having electrical transducer means for emitting and sensing ultrasonic energy and having a body of material adapted to be embedded in the pathway with the top surface of the body being substantially flush therewith and exposed to the precipitation, the transducer means being physically coupled to the body. A circuit causes the transducer means to emit pulses of ultrasonic energy which are reflected as a plurality of reflections from the top surface of the body and from the upper surface of an accumulation of precipitation on the top surface of the body and are respectively returned to the transducer means which in response to the reflected pulses produces corresponding electrical signals.

Abstract: Apparatus for determining the depth of precipitation accumulating on the surface of a pathway, such as an airport runway or the like, includes a sensor having electrical transducer means for emitting and sensing ultrasonic energy and having a body of material adapted to be embedded in the pathway with the top surface of the body being substantially flush therewith and exposed to the precipitation, the transducer means being physically coupled to the body. A circuit causes the transducer means to emit pulses of ultrasonic energy, which are reflected as first and second reflections from the top surface of the body and from the upper surface of an accumulation of precipitation on the top surface of the body and are respectively returned to the transducer which, in response to the reflected pulses, produces corresponding first and second electrical signals.

Abstract: Detection of wet and icy surface conditions on the surface of a pathway is accomplished using a block of electrically insulative material embedded in the pathway with its top surface flush with the surface of the pathway and exposed to atmospheric precipitation. A sensor electrode is encapsulated in the block and is positioned a predetermined distance beneath the top surface of the block so that an accumulation of atmospheric precipitation on the top surface affects the capacitance and conductance between the sensor electrode and the pathway. Provision is made for detecting the presence of impurities such as salt on the block's top surface. A time-varying electrical current is supplied to the sensor electrode at at least two different predetermined frequencies. The apparatus is relatively sensitive to impurities on the block's surface at one of the predetermined frequencies and is relatively insensitive to said impurities at the second predetermined frequency.

Abstract: Apparatus for detecting wet and icy conditions on the surface of a pathway. A block of electrically insulative material is embedded in a pathway with the top surface of the block being substantially flush with the surface of the pathway and exposed to atmospheric precipitation. A sensor electrode is positioned a predetermined distance beneath the top surface of the block and encapsulated in the block so that the accumulation of atmospheric precipitation on the top surface of the block affects the capacitance and conductance between the sensor electrode and the pathway. A time-varying electrical current having an amplitude which is substantially constant and independent of the accumulation of atmospheric precipitation on the top surface of the block is supplied to the sensor electrode. The apparatus also includes an amplifier for amplifying an electrical signal applied to a pair of input terminals thereof.

Abstract: A device for use in determining the depth of water accumulating on the surface of a pathway, such as an airport runway or the like. A block of electrically insulative material is embedded in a pathway with the top surface of the block being substantially flush with the pathway surface and exposed to atmospheric precipitation. A sensor comprising first and second capacitors, each of which has first and second coplanar spaced apart electrodes, is positioned within the block with the electrodes of the first capacitor positioned adjacent to and inclined with respect to the top surface of the block and with the electrodes of the second capacitor being positioned a substantially greater distance from the top surface of the block whereby an accumulation of water on the surface of the block affects the dielectric, capacitance and conductance of the first capacitor without substantially affecting the dielectric, capacitance and conductance of the second.