www.vaisala.com Vaisala Dropsonde RD93

What is a dropsonde? Features/Benefits The Vaisala Dropsonde RD93 is a ▪ For use with Vaisala AVAPS meteorological device that is andAVAPS launched from an aircraft. ▪ Lite dropsonde receiving Descending through the atmosphere systems by parachute, it measures Manufactured under license atmospheric pressure, , ▪ from NCAR relative (PTU) and wind from the point of launch to the ▪ Widely used since 1997 ground. The RD93 is used with the Vaisala AVAPS and AVAPS Lite dropsonde receiving systems. The RD93 transmits data over a telemetry link to the onboard receiving system. The onboard GPS receiver tracks the dropsonde’s horizontal movement as it is borne by the wind. The The Vaisala AVAPS Lite is a receiving dropsonde electronics board has a system for receiving data from one microprocessor for measuring and dropsonde at a time. Small and controlling the sensor module and lightweight, it can be operated with a data transmission. The narrowband laptop PC. transmitter can be set anywhere in the 400 MHz meteorological band. Intellectual property The Vaisala Dropsonde RD93 is a rightsand development general-purpose, precision dropsonde Stable descent The Atmospheric Technology meant for high-altitude drops from A parachute with a patented square- Division (ATD) of the National Center high-speed aircraft. It transmits PTU cone design deploys immediately of Atmospheric Research (NCAR) and wind data at a high data rate. upon launch. It slows and stabilizes developed the hardware and software the RD93’s descent and ensures that for the Vaisala RD93 Dropsonde, the it does not descend with a pendulum Vaisala AVAPS and the Vaisala AVAPS motion. The rate of descent is Lite. The hardware and software are approximately 11 m/s. Mid-sized licensed to Vaisala Inc., USA. NCAR/ and large parachutes, available as ATD and Vaisala are committed to options, provide descent rates of 7 the continuous development of the m/s and 5 m/s respectively. AVAPS and AVAPS Lite hardware and software in accordance with What are the Vaisala the evolving requirements of our avaps and avaps lite? customers. Vaisala AVAPS and AVAPS The Vaisala AVAPS and AVAPS Lite Lite bring together world-leading systems receive, display and store GPS technology and PTU sensor the dropsonde data. TheVaisala technology, the results of Vaisala’s AVAPS can track up to four 60+ years of expertise in atmospheric descending dropsondes at the same measurement. time. This is an essential ability Thousands of RD93 dropsondes in reconnaissance that is are used every year in hurricane carried out with high-speed, high- reconnaissance and other altitude reconnaissance aircraft. meteorological research projects. Technical data

Vaisala Dropsonde RD93 Temperature sensor Weight < 420 g Vaisala THERMOCAP® capacitive bead Size 7 cm in diameter, 41 cm in length Range -90 °C to +60 °C Maximum deployment airspeed 250 kt IAS (= 125 m/s IAS) Resolution 0.1 °C Shelf life 1 year from delivery Accuracy Repeatability * 0.2 °C Response time (when used and measured in Transmitter Vaisala RS80) Frequency range 400 MHz to 406 MHz 6 m/s, 1000 hPa Frequency stability ±3 kHz < 2 s RF power output 100 mW Channel spacing 100 kHz IF bandwidth 20 kHz Harmonic & spurious output >50 dB below the carrier level Relative humidity sensors Vaisala H-HUMICAP® thin film capacitor, Total modulation >2.5 kHz, <3.5 kHz heated twin-sensor design Telemetry range with 325 km Range 0 % to 100 % RH recommended receiving antenna Resolution 1 % RH Accuracy Repeatability * 2 % RH GPS Receiver Response time (when used and measured in Type Commercial code-correlating GPS receiver Vaisala Radiosonde RS92) Channels Tracks up to 8 satellites simultaneously 6 m/s, 1000 hPa, +20 °C < 0.5 s GPS data downlink 1200 baud, digital 6 m/s, 1000 hPa, -40 °C < 20 s Modulation FSK Error checking CRC Horizontal winds Range 0 m/s to 200 m/s PTU Modulation Resolution 0.1 m/s PTU data downlink640 baud, digital Wind measurement accuracy 0.5 m/s RMS Error checking CRC-16

Battery Descent Type Six lithium CR-2 cells in series Descent speeds Voltage >15 VDC RD93 ~11 m/s at sea level Current Max. 235 mA, 200 mA average RD93M (custom order) ~7 m/s at sea level with optional Life 2 hours (operating), 3 years (shelf) mid-size parachute RD93L (custom order) ~5 m/s at sea level with optional large parachute Pressure sensor Descent time for RD93 Vaisala BAROCAP® silicon sensor From 14 km ~15 mins Range 1080 hPa to 3 hPa From 7.5 km ~8 mins Resolution 0.1 hPa *Standard deviation of differences between two Accuracy successive repeated calibrations, Repeatability* 0.4 hPa k = 2 confidence level

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