Rosemount Tank Radar Ab

Saab Rosemount Tank Radar Ab

Anders Jirskog

Olov Edvardsson

Mikael Kleman

Lars Ove Larsson

Niklas Penndal

Kurt Olov Edvardsson

Magnus Ohlsson

Jan Westerling

Valter Nilsson

A radar level gauge having a wave guiding structure arranged to guide a measurement signal towards the surface and to return the reflected signal, and an electromagnetic wave transducer arranged to emit the measurement signal into the wave guiding structure as electromagnetic waves. The electromagnetic wave transducer has a plurality of radiating elements arranged in N&#x2212;1 concentric feeder rings, where a radius of each feeder ring coincides with a radial zero of an electrical field of the H-mode, and feeding circuitry connected to feed the measurement signals from the transceiver circuitry to the radiating elements, thereby causing the electromagnetic wave transducer to excite electromagnetic waves in the H-mode. With this choice of feeder ring radii, the Hmode will not be excited.

Radar level gauge with H-mode wave transducer

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).

Radar level gauging using frequency modulated pulsed wave

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 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.

Frequency modulated radar level gauging

Level gauging including an approximation of a distance to the surface of a product kept in a tank. The approximation is determined by relating an amplitude of a first harmonic of an IF signal with an amplitude of a second harmonic of the IF signal. Basically, each harmonics represents a given distance range. By determining the received power in two or more harmonics, and correlating them to each other, the distance may be estimated. Depending on modulation and other parameters the distance dependence may be very different, and may be selected to suit the application.

MFPW radar level gauging with distance approximation

A radar level gauge system, for determining a filling level of a product contained in a tank, the radar level gauge system comprising a transceiver including a signal generator for generating electromagnetic signals for transmission; a transmitter branch for transmitting the electromagnetic signals; and a receiver branch for receiving electromagnetic signals, the transmitter branch and the receiver branch each being connected to a transceiver input/output terminal. The radar level gauge system further comprises a propagation device for allowing transmitted electromagnetic signals to propagate towards a surface of the product inside the tank, where signals are reflected, and for returning reflected electromagnetic signals back from the surface of the product; processing circuitry connected to the transceiver and configured to determine the filling level based on the reflected electromagnetic signals; and power level adjusting circuitry connected between the transceiver input/output terminal and the propagation device, and configured to adjust a power level of the transmitted electromagnetic signals by a transmission gain factor, and to adjust a power level of the returned reflected electromagnetic signals by a reception gain factor, the transmission gain factor being smaller than the reception gain factor, wherein the power level adjusting circuitry comprises at least one active component.

Radar level gauge system having limited transmission power

A radar level gauge system for determining a filling level of a product contained in a tank, comprising: a transceiver for generating, transmitting and receiving frequency-modulated electromagnetic signals; a transmitting propagating device electrically connected to the transceiver and arranged to propagate transmitted electromagnetic signals towards a surface of the product contained in the tank; and a receiving propagating device electrically connected to the transceiver and arranged to return echo signals resulting from reflections at impedance transitions encountered by the transmitted electromagnetic signals, including a surface echo signal resulting from reflection at the surface, back to the transceiver.

High sensitivity frequency modulated radar level gauge system

A radar level gauge system, for determining a filling level of a product contained in a tank, the radar level gauge system comprising a transceiver including a signal generator for generating electromagnetic signals for transmission; a transmitter branch for transmitting the electromagnetic signals; and a receiver branch for receiving electromagnetic signals. The radar level gauge system further comprises a propagation device for allowing transmitted electromagnetic signals to propagate towards a surface of the product inside the tank, where signals are reflected, and for returning reflected electromagnetic signals back from the surface of the product; processing circuitry connected to the transceiver and configured to determine the filling level based on the reflected electromagnetic signals; power sensing circuitry connected to the transceiver and configured to determine a received power level of received electromagnetic signals; and power level adjusting circuitry provided on the transmitter branch of the transceiver, connected to the power determination circuitry, and configured to adjust a transmitted power level of the transmitted electromagnetic signals in response to the determined received power level of the reflected electromagnetic signals.

Radar level gauge system with adaptive transmission power control

A radar level gauge (RLG) system and method for determining a filling level of a filling material in a tank is disclosed. The RLG system comprises a transmitter for generating and transmitting an electromagnetic transmitter pulse signal, a transmitter controller for controlling means for pulse width adjustment for adjusting the pulse width of the transmitter pulse signal in dependence of at least one application specific condition. Further, the system comprises a signal medium interface connectable to means for directing said transmitter pulse signal towards said filling material and for receiving a reception pulse signal reflected back from said filling material; a receiver for receiving said reception pulse signal from the tank; and processing circuitry for determining the filling level of the tank based on said reflection pulse signal received by said receiver. The application specific condition(s) is e.g. one or several of tank height, level of the filling material, type of filling material, presence of other tank structure providing reflecting surfaces and required accuracy of measurement.

Radar level gauge with variable pulse parameters

A circuit for a radar level gauge for measuring the level of the surface of a product stored in a container, wherein the gauge includes a radar for transmitting microwave signals from a multiband antenna unit towards the surface for receiving microwave signals reflected by the surface and for determining the level based on an evaluation of the time lapsed between the received and the transmitted signals and said radar operating on at least two different frequency bands. The circuit includes: a first microwave provision means for providing a microwave signal of a first frequency band having a first center frequency, a second microwave provision means for providing a microwave signal of a second frequency band having a second center frequency. The ratio between the second and the first center frequency is quantified as at least greater than 1.5:1 and preferably greater than 2:1. Switches are operated by means of a control signal for switching the circuit to operate on said first frequency band or said second frequency band.

Circuit for multifrequency band radar level gauge

A radar level gauge (RLG) is provided for determining a filling level of a filling material contained in a container by transmitting and receiving elliptically or circularly polarized waves. The RLG comprises: a feeding circuitry for feeding and receiving two essentially orthogonal elliptically polarized waveguide modes, one of the modes for transmission and another mode for reception; an antenna for transmitting the waveguide modes towards the filling material and for receiving reflected signals; and a waveguide to provide signals between said feeding circuitry and the antenna. Further, the feeding circuitry comprises: a microwave generating unit (TX); a microwave receiving unit (RX); at least three feeding probes being at least partly exposed to the interior of the waveguide; and a coupling circuitry for transferring and feeding signals between each feeding probe and the microwave generating unit and/or the microwave receiving unit. At least the coupling circuitry and the feeding probes are implemented on a common printed circuit board (PCB), and the printed circuit board is arranged transversely over the waveguide.

Radar level gauge using elliptically or circularly polarized waves

There is provided a radar level gauge using microwaves for measuring a level of a surface of a product in a tank, comprising an antenna for transmitting microwaves to the surface and receiving microwaves reflected by the surface, a measurement circuitry feeding said antenna through a hollow wave guide and said wave guide including at least an antenna wave guide member, at one end couplable to the antenna and at its other end having an opening in an intersection across the wave guide, wherein the radar level gauge further comprises: a dielectric barrier extending along said intersection across the opening of said antenna wave guide member for non-conductively separating said antenna wave guide member from the measurement circuitry, said dielectric barrier having a first side facing the wave guide in a direction towards the antenna wave guide member and said dielectric barrier having a second side facing a direction substantially away from said antenna wave guide member.

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Huskvarna, Sweden

Anders Jirskog