A vehicle-position monitoring system includes liquid-capacitive inclinometer sensor, configured to provide a measurement of grade (θ.sub.grade) of a surface over which a vehicle travels, and an accelerometer to measure acceleration of the vehicle along a principal axis (a.sub.x) of the vehicle along the surface. Direct measurement of the grade (θ.sub.grade) provides a position-tracking system with accurate information to extract acceleration due to motoring and braking (a.sub.MB) from acceleration experienced along the principal axis and track vehicle position without regard to wheel diameter calibration.

A method of measuring the speed of a fluid comprising the following steps: generating a plurality of pseudorandom frequencies (fus_n); for each pseudorandom frequency (fus_n), emitting ultrasound signals into the fluid to travel along a path of defined length; receiving the ultrasound signals; for each received ultrasound signal, producing a travel time measurement, so as to generate for each pseudorandom frequency (fus_n) a predefined number of travel time measurements; for each pseudorandom frequency (fus_n), evaluating the accuracy of the measurements; for evaluating the speed of the fluid, making use of the measurements produced for the pseudorandom frequency that presents the greatest accuracy.

A method of measuring the speed of a fluid comprising the following steps: generating a plurality of pseudorandom frequencies (fus_n); for each pseudorandom frequency (fus_n), emitting ultrasound signals into the fluid to travel along a path of defined length; receiving the ultrasound signals; for each received ultrasound signal, producing a travel time measurement, so as to generate for each pseudorandom frequency (fus_n) a predefined number of travel time measurements; for each pseudorandom frequency (fus_n), evaluating the accuracy of the measurements; for evaluating the speed of the fluid, making use of the measurements produced for the pseudorandom frequency that presents the greatest accuracy.

An apparatus for measuring fluid speed by using the refraction of light is disclosed. The apparatus includes: a channel in which a passage is formed to allow the flow of a fluid; a first and a second light source that are located in any one region of an upper part and a lower part of the channel; a sensor installed in an opposite region of the region where the first and second light sources are located with respect to the channel, to receive the light emitted from the first and second light sources; a speed calculation unit configured to calculate a speed of the fluid by using the intensity of the light received at the sensor.

An apparatus for measuring fluid speed by using the refraction of light is disclosed. The apparatus includes: a channel in which a passage is formed to allow the flow of a fluid; a first and a second light source that are located in any one region of an upper part and a lower part of the channel; a sensor installed in an opposite region of the region where the first and second light sources are located with respect to the channel, to receive the light emitted from the first and second light sources; a speed calculation unit that calculates the speed of the fluid by using a time point at which the intensity of the light received at the sensor changes; and an adjustment unit that is connected to the channel and configured to adjust the flow speed of the fluid based on the calculated speed of the fluid.

The present invention provides a thermal flowmeter having good measurement accuracy by reducing deviation in the flow velocity distribution of a gas under measurement flowing through an auxiliary passage. An auxiliary passage 330 for taking in a portion of a gas under measurement IA flowing through a main passage 124 has a curved passage 32a that bends toward a flowrate measurement element 602. The curved passage 32a has a resistance portion 50 formed therein that applies resistance to the flow of the gas under measurement IA flowing through the outer peripheral side CO of the curved passage 32a so that the pressure loss of the gas under measurement IA flowing through the outer peripheral side CO is high compared to that of the gas flowing through the inner peripheral side CI of the curved passage 32a.

A connection terminal is on a flange of a thermal flow meter. A terminal connection part has a first and a second bent part. The first bent part is bent from a first direction to a second direction. The second bent part has is bent from the first bent part to a third direction. The first and second bent parts are formed such that when connection pin parts of a plurality of the connection terminals and terminal connection parts of the plurality of connection terminals are projected onto a first imaginary plane, an imaginary line L extending along a first direction passing through the projection areas of each of the terminal connection parts of the plurality of connection terminals passes between the projection areas of the connection pin parts from among the connection pin parts of the plurality of connection terminals, that are positioned on both sides.

A method (400) for identifying precipitation (50) includes the steps of: providing (410) a lighting unit (10) having a first photosensor (32), a second photosensor (34), and a controller (22), where the first and second photosensors are vertically spaced by a first distance; receiving (430), by the first photosensor, a first light signal from the precipitation at a first time point (T1); receiving (440) by the second photosensor, a second light signal from the precipitation at a second time point (T2); calculating (450) the amount of time between the first light signal and the second light signal; and calculating (460), based on the first distance and the calculated amount of time between the first light signal and the second light signal, a velocity of the precipitation.

An underwater detector includes a sealed enclosure, inside an infrared sensor module is disposed. The module rotates around a spindle at a fixed angular velocity along a horizontal plane. An electronic compass disposed on the module. A bottom of the sealed enclosure connected to an indicator through a rotary shaft, and the indicator rotates around the rotary shaft on the horizontal plane. The indicator includes a head and tail fin. A light source emits a light beam vertically upwards on the tail fin. The module is configured to trigger, when receiving the light beam, the electronic compass records a real-time direction relative to the spindle, which is processed by a processor module to obtain a direction of the water flow. A spring connects between the head and tail fin. The infrared sensor module transmits a moment of receiving the light beam to the processor module to calculate the water flow.

An improved flow sensor (104) is provided to enable accurate dose measurements to be made with little or no sensor calibration due to highly accurate flow channel cross section. The flow channel is formed as a metal tube (1301). A sensor window (1304) is formed in the side wall of the metal tube (1301), and the flow sensor (1200) is mounted in the sensor window. A flow manifold is formed around the metal flow channel.