Abstract: A self-diagnosing FMCW radar level gauge and a method for providing self-diagnosing with a radar level gauge is provided in a radar level gauge comprising a transceiver, a mixer, a signal propagating device and a signal propagation path connecting the transceiver and the signal propagating device, a filter arrangement and processing circuitry. The filter arrangement provides a filtered intermediate frequency signal. The transceiver outputs either a diagnostic sweep configured such that a reference echo from the signal propagation path is detectable in said filtered intermediate frequency signal, or a measurement sweep configured such that the reference echo is suppressed in the filtered intermediate frequency signal and that a surface echo is detectable. The processing circuitry is configured to self-diagnose the radar level gauge based on the reference echo, and to determine the distance to the surface based on the surface echo.

Abstract: A gauging installation for a tank with a long narrow nozzle providing access to an interior of the tank. The gauging system includes a GWR level gauge with a probe, and a first rigid extension member providing an interior probe mounting position at the end of the nozzle. The probe is configured to guide an electromagnetic transmit signal from a transceiver towards the product inside the tank, and to return the electromagnetic echo signal resulting from a reflection of the electromagnetic transmit signal by a surface of the product. A microwave transmission line connects the transceiver and the probe. With this design the beginning of the probe of the GWR level gauge will be located at the lower end of the nozzle, i.e. at the upper interior of the tank.

Abstract: The present invention relates to a radar level gauge system comprising a signal propagation device; a microwave signal source; a microwave signal source controller; a mixer configured to combine a transmit signal from the microwave signal source and a reflection signal from the surface to form an intermediate frequency signal; and processing circuitry coupled to the mixer and configured to determine the filling level based on the intermediate frequency signal.

Abstract: The present invention relates to a radar level gauge system comprising a signal propagation device; a microwave signal source; a microwave signal source controller; a mixer configured to combine a transmit signal from the microwave signal source and a reflection signal from the surface to form an intermediate frequency signal; and processing circuitry coupled to the mixer and configured to determine the filling level based on the intermediate frequency signal. The microwave signal source is configured to exhibit a phase noise greater than or equal to ?70 dBc/Hz @ 100 kHz offset from a carrier frequency for the transmit signal.

Abstract: The present invention relates to a radar level gauge system comprising a first receiver branch for converting a reflection signal to a first digital measurement signal, and a second receiver branch configured to convert the reflection signal to a second digital measurement signal. The first receiver branch modulates an amplitude of the first measurement signal according to a first gain function, and the second receiver branch modulates an amplitude of the second measurement signal according to a second gain function different from the first gain function. The radar level gauge system further comprises processing circuitry configured to determine the filling level based on the first measurement signal and the second measurement signal.

Abstract: A GWR level gauge system for determining a filling level in a tank. The system comprises a tank, a transceiver, a surface waveguide comprising a single conductor transmission line probe, connected to the transceiver, arranged extending vertically into the tank and configured to guide the electromagnetic transmission signals towards the surface and to guide the reflected electromagnetic signals back to the transceiver; processing circuitry connected to the transceiver and configured to determine the filing level based on received reflected electromagnetic signals; a plurality of retaining elements arranged in fixed positions in relation to an inside of the tank and spaced apart along the probe, wherein each of the retaining elements circumscribes the probe, and is configured to allow movement of the probe in a vertical direction relative the retaining element, and to restrict movement of the probe in a horizontal direction relative the retaining element.

Abstract: A system and method for determining a density of a non-conducting medium in a tank is disclosed where the relationship between a dielectric constant and a density of the medium is known. The system comprises a transceiver, and a waveguide, the waveguide extends towards and into the medium. The system further comprises a first microwave resonator located along the waveguide. The first microwave resonator has a resonance frequency, which depends on a dielectric constant of a medium surrounding the resonator according to a known relationship, and is arranged to reflect a portion in the frequency domain of a signal being guided along the waveguide. The system further comprises processing circuitry connected to the transceiver and configured to determine the resonance frequency based on a received reflected signal, and to determine a density of the medium at the location of the first microwave resonator based on the resonance frequency.

Abstract: A method of determining a filling level of a product contained in a tank using a level gauge system, comprising the steps of: transmitting a first signal towards a surface of the product; receiving a first echo signal; determining a present echo characteristic value based on the first echo signal; and comparing the present echo characteristic value and a stored echo characteristic value. If a difference between the present echo characteristic value and the stored echo characteristic value is greater than a predefined value, the method further comprises transmitting at least a second transmit signal towards the surface; receiving at least a second echo signal; and determining the filling level based on the at least second electromagnetic echo signal.

Abstract: The present invention relates to reflector arrangement for proof test of a radar level gauge and to a radar level gauge system comprising such a reflector arrangement. The reflector arrangement comprises a pliable elongated member for attachment to a fixed structure in the tank; a weight attachable to the pliable elongated member; and a reflector member for reflecting an electromagnetic signal impinging on the reflector plate. The weight is configured to be coupled to the reflector member in such a way that an orientation of the weight determines an orientation of the reflector member.

Abstract: The present invention relates to a method of verifying a measurement accuracy of a level gauge system. The method comprises determining a first measurement value indicative of a time-of-flight of a first electromagnetic reflection signal to a reference reflector and back; determining a measurement unit verification measurement value based on a response signal from a verification arrangement; determining a second measurement value indicative of a time-of-flight of a second electromagnetic reflection signal to the reference reflector and back; and determining a verification result based on the first measurement value, the second measurement value and the measurement unit verification measurement value. Through embodiments of the present invention, it will be verified that the measurement unit is functioning correctly and that level gauge system works as it should also after being reconnected to the propagation device.

Abstract: A method of determining a filling level comprising transmitting a first transmit signal exhibiting a first ratio between bandwidth number of frequencies; receiving a first reflection signal; mixing the first transmit signal and the first reflection signal to form a first intermediate frequency signal; and determining a first data set indicative of a first set of surface echo candidates based on the first intermediate frequency signal. The method further comprises transmitting a second transmit signal exhibiting a second ratio between bandwidth and number of frequencies being different from the first ratio; receiving a second reflection signal; mixing the second transmit signal and the second reflection signal to form a second intermediate frequency signal; and determining a second data set indicative of a second set of surface echo candidates based on the second intermediate frequency signal. The filling level determined based on subsets of the first and second sets.

Abstract: A method for determining the filling level of a product in a tank using electromagnetic signals, comprising: a) generating a transmission signal having a predetermined length; b) propagating the signal towards the product; c) receiving a reflected signal; d) determining whether the received signal overlaps the transmitted signal in the time-domain; e) setting an overlap-parameter to 1 if overlap is detected, otherwise setting the overlap-parameter to 0; if the state of the overlap parameter is not changed and if no overlap is detected, generate a signal having a length exceeding the previous length and repeat step b); and if the state of the overlap-parameter is not changed and if an overlap is detected, generate a signal having a length shorter than the previous length and repeat step b); and if the state of the overlap-parameter is changed, determine the filling level based on the length of the transmitted signal.

Abstract: A radar level gauge and a method for measurement of a distance to a surface of a product in a tank are disclosed. The radar level gauge comprises transceiver circuitry configured to transmit and receive electromagnetic signals, the transceiver circuitry comprises a frequency stabilizing feedback loop configured to generate the electromagnetic transmit signal in the form of a frequency sweep. The frequency stabilizing feedback loop is configured to generate an oscillation, forming a sinusoidal modulation of the frequency sweep. The radar level gauge further comprises a second mixer configured to mix an intermediate frequency signal and an integer multiple of the frequency of the sinusoidal modulation to provide an adjusted intermediate frequency signal, and processing circuitry configured to determine the distance based on the adjusted intermediate frequency signal. By providing a frequency sweep comprising a sinusoidal modulation, an improved sensitivity is achieved by the radar level gauge and method.

Abstract: The present invention relates to a guided wave radar level gauge comprising a transceiver, processing circuitry and a single conductor probe comprising at least two elongate probe sections. A connector extending from a first end of the probe section comprises: an abutment portion having a diameter smaller than a diameter of the probe section, an intermediate portion, having a diameter smaller than the abutment portion, arranged between the probe section and the abutment portion and an outside threaded portion. A second end portion of the probe section comprises a sleeve comprising an inside threaded receiving portion receiving the connector; a passage through a sidewall of the sleeve being located off-center in relation to a longitudinal central axis of the probe section. The probe further comprises a locking pin to be arranged in the passage locking two assembled probe sections by limiting movement of the abutment portion in a longitudinal direction.

Abstract: A radar level gauge system for determining a filling level in a tank. The radar level gauge system comprises a transceiver, a horn antenna having a first opening connected to the transceiver and a second opening facing a surface of the product in the tank, and processing circuitry connected to the transceiver for determining the filling level based on an electromagnetic surface reflection signal. The horn antenna is configured in such a way that an electrical distance from the first opening to the second opening, along a path defined by an intersection between a wall of the horn antenna and a half-plane starting from and extending in parallel with a cone axis of the horn antenna, is different for different orientations of the half-plane with respect to the cone axis. Hereby, disturbance from an antenna reflection signal can be reduced, which provides for improved measurement of high filling levels.

Abstract: The present invention relates to a method comprising providing an activation signal from a wireless communication unit to a measurement unit to switch the measurement unit from its inactive state to its active state; providing a measurement request signal to the measurement unit to request measurement of a filling level of a product in a tank; and thereafter switching the wireless communication unit from its active state to its inactive state. The measurement unit measures the filling level and provides a measurement ready signal to the wireless communication unit; the wireless communication unit is switched from its inactive state to its active state in response to the measurement ready signal received from the measurement unit; the wireless communication unit retrieves the value indicative of the filling level from the measurement unit; and wirelessly transmits the value indicative of the filling level to the remote device.

Abstract: The present invention relates to a guided wave radar level gauge system for determining a filling level of a product contained in a tank. The level gauge system comprises a transceiver for transmitting and receiving electromagnetic signals, a probe extending into the tank and configured to guide the signals towards the surface and to guide reflected signals back to the transceiver, processing circuitry for determining the filing level based on the reflected signals, and a plurality of spacing elements arranged on the probe. Each spacing element comprises a shell structure having an ellipsoidal shape defining an ellipsoidal space, first and second shell openings at first and second locations of the shell, such that a passage through the shell openings defines a passage through the spherical space, wherein the probe extends through the passage, and a plurality of flow openings allowing fluid flow between the exterior and interior of the shell.

Abstract: A two-channel directional antenna for use in a radar level gauge. The antenna comprises a partition wall dividing the antenna into a first partition for emitting an electromagnetic transmit signal, and a second partition for receiving an electromagnetic echo signal, the partition wall having an outer potion located downstream in a direction of radiation of the antenna. The partition wall comprises an electromagnetic de-coupling structure, which is arranged to reduce any leakage of electromagnetic energy from the transmit signal into the echo signal. The electromagnetic de-coupling structure according to the present invention ensures that the leakage of transmit signal into the received signal is reduced to a satisfactory level.

Abstract: The invention relates to a test arrangement comprising a waveguide, a first signal reflecting device and a second signal reflecting device. The first signal reflecting device is configured to reflect an electromagnetic signal traveling along the waveguide from the second signal reflecting device back towards the second reflecting device and to allow, at least during a time period, an electromagnetic signal traveling along the waveguide from the second signal reflecting device towards the first signal reflecting device to pass the first signal reflecting device. Hereby, a selected number of passages through a waveguide can be used to simulate passage through a much longer waveguide, and that this allows for use of a high-quality waveguide which would otherwise be too bulky, too heavy or too expensive to use depending on field of application.

Abstract: A method for measurement of a distance to a surface of a product kept in a tank method comprises transmitting a pulse train of distinct carrier wave pulses having a duration greater than 1 microsecond and shorter than 100 milliseconds, the pulse train has an average duty cycle of less than 50 percent, each pulse has a defined center frequency, selected according to a frequency scheme within a predetermined frequency range, greater than 5% of an average center frequency. The method further comprises correlating actual phase properties of received pulses with expected phase properties to provide an updated estimation of the distance. The present invention is based on transmitting a set of carrier wave pulses, each having a distinct frequency selected within a frequency range. The method is therefore referred to as a Frequency Modulated Pulsed Wave (FMPW).