Upload
phungque
View
221
Download
0
Embed Size (px)
Citation preview
RPG_FMCW_TN_2015.docx RPG Radiometer Physics GmbH Birkenmaarstr. 10 53340 Meckenheim, Germany
01/2015 +49 (0) 2225 99981 – 0
www.radiometer-physics.de [email protected]
All data and specifications are subject to change without notice! © Radiometer Physics GmbH 2014
FMCW Cloud Doppler RadarRPG‐FMCW‐94 (SP/DP)
1
FMCW Cloud Radar Applications
● High resolution vertical profiles of dBz
● Velocity profiles from Doppler spectra
● LWC (Liquid Water Content) profiles
● 3D cloud studies (with optional scan mechanism)
● Dual-polarization option for hydrometeor classification
● Now-casting, cloud formation, fog observation
● Urban weather in metropolitan areas
● Weather modification, cloud process studies
● Operational deployments in all weather conditions
Unique Features ● High-Power transmitter with 2 W transmitted power (continuous wave)
● Low-Noise receiver with 300 K system noise temperature (equals 3 dB noise figure)
● Built-in passive radiometric channel at 89 GHz using the same optics and same LNA
● Provides radiometer-derived LWP to constrain synergetic LWC profile retrievals
● Corrects the received power by the thermal emission of the cloudy-sky (which can be significantly higher than the minimum detectable reflected power
● Radar centre frequency adjustable (software selectable) between 92.3 and 95.7 GHz (supporting a flexible application for operating permissions)
● Chirp parameters and selection fully adaptable to observation modes (high/low modes, emphasis on large Doppler ranges, or higher Doppler accuracy) by software
● Operating software with Z-LWC retrievals, attenuation correction, particle classification
RPG_FMCW_TN_2015.docx RPG Radiometer Physics GmbH Birkenmaarstr. 10 53340 Meckenheim, Germany
01/2015 +49 (0) 2225 99981 – 0
www.radiometer-physics.de [email protected]
All data and specifications are subject to change without notice! © Radiometer Physics GmbH 2014
FMCW Cloud Doppler RadarRPG‐FMCW‐94 (SP/DP)
2
Concept ● Principle: time lag ∆ between
continuously emitted and received frequency chirps gives a spectrum of beat frequency ∆ .
● Beat frequency spectrum
contains ranging information with a resolution of ∆ /2∆ .
● Doppler shift provides velocity
profiles.
Design
● Bi-static design with shielded and accurately levelled optics (antenna decoupling < –100 dB).
● Generated HF signal is split up
into emitting and receiving branch. ● Receiving branch is mixed with signal from
amplified signal received via antenna. ● Mixer down-converts signal to IF range, where
it is filtered, amplified and digitized.
RPG_FMCW_TN_2015.docx RPG Radiometer Physics GmbH Birkenmaarstr. 10 53340 Meckenheim, Germany
01/2015 +49 (0) 2225 99981 – 0
www.radiometer-physics.de [email protected]
All data and specifications are subject to change without notice! © Radiometer Physics GmbH 2014
FMCW Cloud Doppler RadarRPG‐FMCW‐94 (SP/DP)
3
First Measurements
RPG_FMCW_TN_2015.docx RPG Radiometer Physics GmbH Birkenmaarstr. 10 53340 Meckenheim, Germany
01/2015 +49 (0) 2225 99981 – 0
www.radiometer-physics.de [email protected]
All data and specifications are subject to change without notice! © Radiometer Physics GmbH 2014
FMCW Cloud Doppler RadarRPG‐FMCW‐94 (SP/DP)
4
Specifications
Parameter Specification
Centre Frequency 94 GHz (λ=3.19 mm) ± 100 MHz typical, (adjustable by software between 92.3 and 95.7 GHz)
IF range 350 kHz to 3 MHz
Transmitter power 2 W typical (solid state amplifier)
Antenna type Bi-static Cassegrain with 500 mm aperture
Antenna gain 52.3 dB
Beam width 0.45° FWHM
Polarisation V (optional V & H)
Rx System Noise Figure 3 dB (300 K system noise temperature)
Typical Dynamic range (Sensitivity) with 2 W transmitter
-60 dBz to +20 dBz (at 500 m height / 5 m resolution) -50 dBz to +20 dBz (at 2 km height / 10 m resolution) -47 dBz to +20 dBz (at 4 km height / 30 m resolution) -36 dBz to +20 dBz (at 10 km height / 30 m resolution)
Ranging 100 m to 12 km typical, 16 km maximum
Maximum vertical resolution
1 m (range: 0.1 km – 0.6 km), 2 m (range: 0.6 km – 1.0 km), 4 m (range: 1.0 km – 2.5 km), 8 m (range: 2.5 km – 5.0 km), 16 m (range: 5.0 km – 12.0 km)
Calibrations (automatic) Power monitoring of the transmitter, plus Dicke-switch at receiver (for radar and passive radiometer channel)
Calibrations (maintenance) Liquid nitrogen receiver calibration, external reference sphere
A/D Sampling rate 8.2 MHz (data processing between 0.35 and 3 MHz)
Data processing system High-Performance embedded PC
Sampling rate (full profiles) 4 s typical (flexible, can be adjusted to 1 s, 8 s, etc)
Doppler range ± 10 m/s unambiguous velocity range
Doppler resolution ± 15 cm/s
Chirp variations 3 typical, 10 possible, re-programmable “on-the-fly”
Passive channels 89 GHz for integral LWP detection + radar sensitivity correction
Control connection TCP/IP connectivity via fibre optics data cable to internal PC
Operation software Real time visualization, real time data extraction, real time control (adaptive observation modes depending on context)
Data products (available as files)
Reflectivity, Doppler-velocity, Doppler Spectra, LWC profiles. Data level concept: L1: calibrated dBZ, L2: retrieved data
Data formats netCDF (CF convention), proprietary binary, ASCII
Additional sensors Automatic weather station with P, T, RH, RR, Snow, WS, WD
Scanning / mounting Baseline: Mounted on a fixed stand of 0.5 m height Optional: Scanner unit for full sky scanning capability
Dimensions (L × W × H with antennas): 115 cm × 56 cm × 82 cm (L × W × H main box only): 80 cm × 40 cm × 40 cm
Weight Approx. 80 kg without stand or scan mechanism