Vaisala WRK200 Technical data

Vaisala Weather Radar WRK200

Dual polarization adds new dimension

The Vaisala Weather Radar WRK200 is a dual polarization C-band Klystron Doppler Weather Radar. The radar operates in either Simultaneous Transmit and Receive of H and V (STAR) mode or Linear Depolarization Mode (LDR) mode , during which H alone is transmitted and both are received. The polarization variables, depending on the mode, are ZDR, RHOHV, PHIDP, KDP and LDR. However, the goal of polarization radar is not only to produce and display these outputs; it is also to expand the capabilities of the radar for the operational forecaster.

The WRK200 provides the following benets:

• Hydrometeoridentification

• Attenuationcorrection

• Dataqualityimprovement

• Improvedrainfallestimates,

based on KDP

S-band performance at a C-band price

Attenuation by intervening heavy precipitation has been a long-standing problem with C-band weather radars, making S-band radars preferable, especially in tropical environments where heavy rain is common. However, with dual polarization, the radar performs accurate, real-time attenuation corrections. The benet is that you can obtain the same precipitation measurement accuracy using the WRK200 as with an S-band system that costs typically two or three times more.

More accurate precipitation measurement

Eliminating non-meteorological targets and correcting attenuation can substantially improve precipitation

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Features/Beneﬁts

Vaisala’s light-weight, semi-

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yoke-style pedestal

1 degree beamwidth low side

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lobe antenna

>35 dB integrated cross-

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polarization isolation

Comprehensive BITE

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Improved interference filtering

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Feed forward control loop

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to allow extremely fast and precise antenna movement

Dual channel digital IF receiver

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Precision horizontal and

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vertical beam matching

Built around Vaisala Sigmet

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RVP900 signal processor

Integral flat screen display for

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local maintenance

Remote control/monitoring

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Rainfall estimation based on

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KDP

Accurate attenuation

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correction

250 kW klystron transmitter

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with low-maintenance solidstate modulator

Option: Built-in dual channel

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receiver calibration

measurement. However, the WRK200 goes further by providing KDP-based measurement of the precipitation rate. Unlike the reectivity (Z), KDP is directly proportional to the precipitation rate, independent of the radar calibration and unbiased by intervening clutter or partial beam blockage. This makes the KDP very robust in measuring moderate and heavy rain.

Technical data

Transmitter

Type Klystron VKC8387 Operating frequency range 5.6 - 5.65 GHz Peak power 250 kW Average power max 550 W Duty cycle 0.0022 Pulse widths Typical 0.5, 0.8, 1.0, 2.0, max 5 µs PRF 250 to 2125 Hz Modulator Solid state Modes STAR or LDR Phase stability ≤0.1 deg rms

Antenna

Type Center-fed parabolic reﬂector Diameter 4.5 m Gain (typical) 45 dB Beam width <1 degree Peak side lobe (typical) -28 dB Peak on horizontal axis (typical) -33 dB Integrated cross-pol isolation ≤ -35 dB H/V alignment (squint angle) <0.1 degrees Weight 620 kg

Pedestal

Type Semi yoke elevation over azimuth Elevation range -2 to 108 degrees Maximum scan rate 40 deg/sec Acceleration 20 deg/sec Position accuracy 0.1 deg Weight 910 kg (total with antenna 1530 kg) Motors Brushless AC servo

RF-to-IF Receiver

Type Dual stage, dual channel IF downconverter Dynamic range (1µs pulse) >96 dB (option >110 dB) IF frequency 442/60 MHz Image rejection >50 dB Phase stability 0.1 deg rms Tuning range 5.5 - 5.7 GHz Noise ﬁgure

< 2 dB

Digital IF Receiver and Signal Processor RVP900

Type Vaisala Sigmet RVP900 IF digitizing 16 bits, 100 MHz in 5 channels Range resolution N*15 m Number of range bins Up to 4050 Velocity dealiasing Dual PRF 2x, 3x, 4x Range dealiasing by phase coding Clutter ﬁlters ﬁxed, adaptive or GMAP to >60 dB clutter

System Speciﬁcations

PHYSICAL DIMENSIONS

Cabinet (w x h x d) 1400 x 1800 x 1300 mm Cooling: Air-conditioned and forced air Weight 992 kg Total height 1890 mm

CABINET ENVIRONMENT

Operating +5 °C to +40 °C, 0 to 95 %RH, non condensing Recommended +15 °C to +25 °C Storage -50 °C to +50 °C without oil

-10° to +50˚C with oil

ANTENNA/PEDESTAL ENVIRONMENT

Operating -40 °C to +55 °C, 0 to 95 %RH, non condensing Storage -50 °C to +60 °C

INPUT POWER

Voltage 230/400 VAC ±10 %, 50 - 60 Hz ± 5 %

POWER CONSUMPTION

Cabinet 8720W max. with UPS

7850W max. without UPS

Antenna/pedestal 1050 W (max), 200 W (typical)

Options

Radome 6.7 m, foam core sandwich, random panel Automatic calibration Forward and reverse transmitted power monitoring

cancellation

Radar Controller

Type Vaisala Sigmet RCP8 with IRIS/Radar Scan modes PPI, RHI, Volume, Sector, Manual Local display Real time, ascope, BITE, products

For more information, visit www.vaisala.com or contact us at sales@vaisala.com

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