Rosemount Tank Radar Ab

Saab Marine Electronics Ab

Mikael Kleman

Lars Ove Larsson

Anders Jirskog

Leif Nilsson

Jan Westerling

Lennart Hägg

Per Holmberg

A radar level gauge comprising transceiver circuitry, a propagation device and processing circuitry for determining a value of the process variable based on a relationship between a transmit signal and a return signal. The gauge has a DC/DC converter connected to a power supply interface, and configured to convert a first voltage to a second voltage, lower than the first voltage, and an energy storage. The gauge further has a switch, connected between the DC/DC converter and the energy storage, the switch having a non-conducting state for disconnecting the energy storage from the DC/DC converter when the transceiver circuitry is active, and a conducting state for connecting the energy storage to the DC/DC converter only when the transceiver circuitry is inactive.

Radar level gauge with disconnection of energy store

A radar level gauge comprising a housing enclosing a compartment providing explosion proof protection, RLG circuitry located inside compartment, which circuitry is incompatible with intrinsic safety requirements, and a signal propagation device located outside the compartment. The housing has an explosion proof first signal passage providing a transmission line for the microwave transmit signal, and an explosion proof second signal passage in providing a two-wire interface for electrically conductively connecting the radar level gauge to an intrinsically safe system located externally of the radar level gauge. Further, the RLG includes an electrical barrier connected between the RLG circuitry and the two-wire interface, the electrical barrier preventing energy and/or thermal energy in the RLG circuitry from compromising the intrinsic safety of an intrinsically safe system connected to the two-wire interface.

Explosion proof radar level gauge

A radar level gauge system controllable between a measurement state and a signal processing state. In the measurement state a first timing signal circuit is enabled, a microwave signal source generates a transmit signal with a time-varying frequency being related to first timing signals from the first timing signal generating circuitry, and a sampler samples a mixer signal at sampling times related to the first timing signals. in the signal processing state, the first timing signal circuit is disabled, and a signal processor determines the filling level based on the sampled values of the mixer signal using second timing signals from a second timing signal generating circuit.

FMCW radar level gauge with enhanced timing control

A method for providing narrow-band interference unaffected measurement of a distance to a surface of a product kept in a tank, comprising mixing a return signal with a transmit signal to provide an intermediate frequency signal, and determining the distance, based on the intermediate frequency signal. The step of determining the distance further comprises dividing the intermediate frequency signal into a plurality of frequency portions, wherein each frequency portion corresponds to a frequency interval of the transmit signal, identifying disturbed frequency portions as frequency portions affected by narrow-band interference, and determining the distance based on frequency portions being unaffected by narrow-band interference. By dividing the IF-signal into frequency portions corresponding to frequency intervals of the transmit signal, frequency intervals where narrow-band interferences are present may be detected.

Radar level gauge with signal division

A radar level gauge arrangement for determining the fill level of a filling material in a tank is disclosed, which arrangement is mounted on a hatch of a tank and/or on a support which is adapted to be mounted on a hatch of a tank. The arrangement comprises a transmitter for transmitting measuring signals at least along a first axis for determining the fill level of the tank; a receiver for receiving echo signals corresponding to the distance to the surface; a first processing circuitry for receiving the echo signals and to determine a fill level of the tank based on the echo signal; an inclinometer attached to the support and adapted to generate an inclination output corresponding to the inclination relative the surface normal; a second processing circuitry for generating, based on the inclination output, an angular output when there is an angular difference between the first axis and the surface normal. The arrangement also comprises a presenter for communicating information about the angular difference externally of said system, or a communication path for communicating the angular output to said first processing circuitry.

Radar level gauge inclination system

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.

Self-diagnosing FMCW radar level gauge

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 &#x2212;70 dBc/Hz @ 100 kHz offset from a carrier frequency for the transmit signal.

Low power radar level gauge system with integrated microwave circuit

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.

Low power radar level gauge system

The present invention relates to a radar level gauge system comprising PLL circuitry for generating an output signal. The PLL circuitry is configured to indicate a lock state of the PLL circuitry; and signal modifying circuitry is connected to the PLL circuitry for receiving the output signal and for modifying at least one property of the output signal for forming the transmit signal. The signal modifying circuitry is arranged and configured to receive a PLL status signal indicative of the lock state of the PLL circuitry, and to modify the at least one property of the output signal in response to the PLL status signal indicating that the PLL circuitry is in a locked state.

FMCW radar level gauge with lock state control

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.

Filling level determination using transmit signals with different frequency steps

A level gauge using microwaves to determine a distance to a surface of a product in a tank, wherein a measurement signal comprises a first frequency sweep, and a second frequency sweep, and a mixer is arranged to mix the measurement signal with an echo signal to form a first IF signal based on the first frequency sweep, and a second IF signal based on the second frequency sweep. Processing circuitry is adapted to sample the first IF signal and the second IF signal, to form a combined sample vector including samples from each tank signal, and to determine the distance based on the combined sample vector. By combining the samples from two (or more) different sweeps, the number of samples and the bandwidth can both be increased, thus maintaining the range L. However, as the samples are obtained from two separate sweeps, the sweep time for each individual sweep does not need to be increased, and the average power consumption can be maintained.

FMCW-type radar level gauge

A radar level gauging system comprising a microwave unit for transmitting and receiving first microwaves having a first and second distinguishable characteristics, a microwave absorber adapted to be arranged in a bottom region of the tank and adapted to absorb electromagnetic energy of microwaves having one of the first and second characteristics, and processing circuitry adapted to determine the product level based on a relationship between transmitted and received microwaves. The system thus emits microwaves in two channels, and the absorber is arranged to absorb energy in only one of the channels. Using the absorbed channel, it is possible to obtain a measurement with very limited interference from the bottom, which thus will be accurate also for levels close to the bottom. Using the unabsorbed channel, it is possible to obtain a reference measurement of the distance to the reflecting part of the absorber, thus enabling verification of the of the system.

Radar level gauging system

A method and system for determining a product level in a tank which determine a first level measure using emission of electromagnetic waves into the tank, detect a differential pressure, determine an observed density based on the detected differential pressure and the first level measure, and determine a second level measure based on the observed density and a currently measured differential pressure. The present invention is based on the realization that a level measurement based on differential pressure and an observed density can provide a valuable redundant level measurement, which can provide increased reliability and enable detection of errors.

Redundant level measurement in radar level gauging system

A liquid level measuring gauging system including a radar antenna, a plurality of functionally independent radar measuring channels, and a feeder operably connected with the channels and operable to feed microwave signals of the channels to the antenna.

Method and device for liquid level measurement

The invention relates to a method and a device for measuring a level in a receptacle using radar. Via an aerial ( ) directed down into the receptacle, an electromagnetic wave is transmitted and a reflected and time-delayed wave is received, the level being calculated from the time delay. Via one and the same aerial ( ) at least two waves are transmitted and received, which are mutually distinguishable by a detectable characteristic for each wave. The device according to the invention is characterized in that connected to the aerial ( ) is at least one further radar measuring channel ( ), the radar waves of which are mutually distinguishable and distinguishable from the radar wave used in a first radar measuring channel.

Growing community of inventors

Vreta Kloster, Sweden

Mikael Kleman