MODEM Upper-Air Radiosounding System _____ Latest developments

SR2K2 desktop station

SR2K2 Receiver n Light and compact n Dim:Half 19’’ rack 3U n Weight : 3,5 kg n Consumption: 15W n Front panel which opens for easy maintenance n Auto-test and diagnostics SR2K2 rack includes : n Decoder board, n 400 MHz receiver board, n GPS board (12 channels), n Power supply board, n Barometer board A built-in barometer board provides automatically launch area ground pressure to the software. There is no risk to forget updating the value just before the launch. Nevertheless, the software will accept manual entry from the operator.

ICAR module Interface of Calculation and Analysis of Radiosounding New software module developed by Modem’s engineers for edition of WMO formatted messages, aerological reports and sounding analysis

New generation ground check n It looks like a plastics box with a transparent door and it can be set on a table or wall-mounted. The ground check system allows two simultaneous functions. One is the calibration of temperature and humidity sensors prior launch. Sensor calibration is preformed in ambient atmosphere without using any desiccant salt. Placing the sonde into the box doesn’t need direct handling of sensor boom, reducing risk of damage and contamination of sensitive elements. The second function consists in GPS initialization of the radiosonde. Thanks to the built-in GPS repeater antenna, indoor sonde initialization is performed while the sensor calibration is in progress. It is no longer necessary to place the sonde outdoor.

Dual antenna system MODEM developed as an option, a dual antenna system particularly designed for shipboard station when deck superstructure doesn’t allow ideal installation of a unique antenna. There is also another application for tropics areas where wind flow often brings back the sonde overhead the ground station at the end of the flight. In this case, we offer to combine a basic antenna and a turnstile antenna with a predominant vertical diagram. Both manual or automatic reception modes are available. Running the latest mode, the software will shift automatically to the antenna receiving the best signal. Basic antenna 80 cm long Turnstile antenna - Ø 30 cm

Portable version SR2K2-P portable system Beside the basic desktop station, Modem has developed a portable version. SR2K2-P is specially designed for temporary field operations on different sites. The receiving system is integrated in a very compact and robust suitcase including a laptop. During transport, antennas and cables are protected into their own smart foam bag.

Others configurations SR2K2 is also available along others different configurations fitted to specific applications but all with the same functionalities. Military mobile station French ASAP station with duplication

GPSonde M2K2 (WMO Code 56)

Pressure is calculated from GPS altitude - No pressure sensor Modem’s GPS antenna is an original design for optimization of satellite signal reception in spite of unusual move due to strong pendulum. M2K2 GPSonde offers three connectors for additional sensors. It is fully compatible with ozone sounding without using the costly interface board traditionally necessary M2K2 conception refers to the highest technology in this matter and is fully compliant with the recent ETSI standard for radiosonde transmitter.

M2K2 board

GPS windfinding n GPS Differential calculation provides both position along 3 axes (Latitude, Longitude, Altitude) and speed components along 3 axes (Vx, Vy, Vz) n Therefore, we have 2 two radically different methods for wind speed determination :  Speed derived from GPS position (Geometric calculation)  Doppler measurement performed on instant speed Our system combines both possibilities choosing for each data frame the more appropriate one to get the best quality.

New generation dereeler A new generation dereeler with field-proven efficiency is delivered along M2K2 GPSondes Remove the sticky band Open the deereler Attach the dereeler to the balloon train

System Distinctive Features n Full 3D GPS system with differential calculation (DGPS) n Built-in barometer n Built-in GPS repeater n Small omnidirectionnal radio antenna n Optional automatic dual antenna system n Easy maintenance (Auto tests and diagnostics) n No pressure sensor - Pressure is calculated from GPS altitude providing the best performance n Radiosonde powered with alkaline dry cells instead of water activated battery n Remarkable percentage of data availability >98% n New generation dereeler with field-proven efficiency

Radiosounding systems Z.A. de l’orme à bonnet – Chevannes - France Patrick Charpentier, Georges Ricaud, Rémy Pépin