A pressure sensor with calibration device includes a casing, a diaphragm, a sensing element, a medium, and at least one calibration element. The diaphragm is disposed on the casing, wherein the casing and the diaphragm define an accommodating space. The sensing element is disposed in the casing. The medium is filled in the accommodating space and in contact with the sensing element. The at least one calibration element is adjustably disposed at the casing and extended into the accommodating space to be in contact with the medium, wherein when the at least one calibration element is moved relative to the casing in a direction toward the accommodating space or in a direction away from the accommodating space, the at least one calibration element changes the pressure applied to the medium. The pressure sensor with calibration device adjusts the pressure value sensed by the sensing element via the calibration element.

A pressure sensor includes a Wheatstone bridge circuit including a first resistor, a second resistor, a third resistor, and a fourth resistor having matching output characteristics. The pressure sensor further includes a first trim resistor in series with the Wheatstone bridge circuit, wherein the first trim resistor has output characteristics matching the output characteristics of the first resistor, the second resistor, the third resistor, and the fourth resistor of the Wheatstone bridge. The pressure sensor additionally includes a second trim resistor in parallel or a parallel loop with the Wheatstone bridge circuit, wherein the second trim resistor has output characteristics matching the output characteristics of the first resistor, the second resistor, the third resistor, and the fourth resistor of the Wheatstone bridge.

A method for estimating the pressure measurement bias of a barometric sensor in a wireless terminal. A location engine using the method generates an enhanced estimate of the measurement bias. The location engine generates the enhanced estimate based in part on relatively coarse estimates of the elevation of the wireless terminal. The coarse estimates are used to generate instantaneous estimates of measurement bias and bias uncertainty. As needed, the location engine adjusts the instantaneous estimate of bias uncertainty, in order to reflect an instantaneous estimate of measurement bias that is recognized as being in error. The adjustment is based on what is expected as a probable measurement bias value for the particular wireless terminal. Once the location engine generates the enhanced estimate of measurement bias, it can generate improved estimates of elevation of the wireless terminal.

A method for estimating the pressure measurement bias of a barometric sensor in a wireless terminal. A location engine using the method generates an enhanced estimate of the measurement bias. The location engine generates the enhanced estimate based in part on relatively coarse estimates of the elevation of the wireless terminal. Each coarse estimate of elevation is often generated from noisy measurements, such as measurements of signals transmitted by Global Positioning System (GPS) satellites, and has an associated uncertainty. The location engine accounts for the uncertainty in these estimates of elevation by applying an optimal estimation technique, such as Kalman filtering, and by compensating for environment-related effects. Compensating Includes filtering across a plurality of lateral locations and imposing a lower bound of bias uncertainty at the lateral locations. Once the location engine generates the enhanced estimate of measurement bias, it can generate improved estimates of elevation of the wireless terminal.

The present disclosure describes methods and systems for automatically detecting and calculating an offset of an engine-based pressure measurement transducer after engine shutdown, and applying a correction factor to subsequent pressure measurements of the transducer once the engine is in operation.

The present invention makes it possible to, even when a stainless steel is adopted in a diaphragm: prevent the diaphragm and a strain sensor from exfoliating from each other; be hardly susceptible to the influence of temperature in an operating environment; not allow the sensitivity of a pressure sensor to be dominated only by the mechanical characteristic of a material constituting the diaphragm; and increase the degree of freedom in design of members constituting the pressure sensor. A pressure sensor according to the present invention is, in order to solve the above problems, characterized in that: the pressure sensor has a diaphragm deforming by the pressure of a fluid, an elastic body covering the whole surface of the diaphragm and joining to the diaphragm on one side, and a strain sensor being arranged by joining on the other side of the elastic body and on an end side apart from a position corresponding to the center of the diaphragm and detecting the deformation of the elastic body working together with the deformation of the diaphragm as a strain; and the elastic body is formed of a material having a linear expansion coefficient close to the linear expansion coefficient of a material constituting the strain sensor.

The present invention makes it possible to, even when a stainless steel is adopted in a diaphragm: prevent the diaphragm and a strain sensor from exfoliating from each other; be hardly susceptible to the influence of temperature in an operating environment; not allow the sensitivity of a pressure sensor to be dominated only by the mechanical characteristic of a material constituting the diaphragm; and increase the degree of freedom in design of members constituting the pressure sensor. A pressure sensor according to the present invention is, in order to solve the above problems, characterized in that: the pressure sensor has a diaphragm deforming by the pressure of a fluid, an elastic body covering the whole surface of the diaphragm and joining to the diaphragm on one side, and a strain sensor being arranged by joining on the other side of the elastic body and on an end side apart from a position corresponding to the center of the diaphragm and detecting the deformation of the elastic body working together with the deformation of the diaphragm as a strain; and the elastic body is formed of a material having a linear expansion coefficient close to the linear expansion coefficient of a material constituting the strain sensor.

A pressure sensor including a housing with a sensing element therein. A communication passageway is formed in the housing. The sensing element is in fluid communication with an outside of the housing through the communication passageway. The pressure sensor is further provided with a compensating structure, so that when a contact force is increased due to occurrence of a volume expansion of a liquid passed into the housing through the communication passageway, the compensating structure is used to compensate the volume expansion. A plug may also be used with the pressure sensor. The pressure sensor is such that when the liquid within the pressure sensor has an increased volume due to being frozen, such increased volume can be compensated, so as to prevent the components of the pressure sensor from being damaged.

A pressure sensor including a housing with a sensing element therein. A communication passageway is formed in the housing. The sensing element is in fluid communication with an outside of the housing through the communication passageway. The pressure sensor is further provided with a compensating structure, so that when a contact force is increased due to occurrence of a volume expansion of a liquid passed into the housing through the communication passageway, the compensating structure is used to compensate the volume expansion. A plug may also be used with the pressure sensor. The pressure sensor is such that when the liquid within the pressure sensor has an increased volume due to being frozen, such increased volume can be compensated, so as to prevent the components of the pressure sensor from being damaged.

A differential pressure transmitter is disclosed, which comprises a body for housing a high-pressure sensor and a low-pressure sensor, a plurality of high-pressure process connectors formed in said body and fluidly coupled to said high-pressure sensor for transmitting a first pressure of a process fluid to said high-pressure sensor, each of said high-pressure process connectors comprising a conduit having an opening for receiving the process fluid, a plurality of low-pressure process connectors formed in said body and fluidly coupled to said low-pressure sensor for transmitting a second pressure of a process fluid to said low-pressure sensor, each of said low-pressure process connectors comprising a conduit having an opening for receiving the process fluid, wherein said second pressure is equal to or less than said first pressure, wherein said openings of the high-pressure connectors are spaced relative to said openings of the low-pressure connectors to allow a plurality of pair-wise connections to the process fluid.