A Scalable Radar Wind Profiler for Boundary Layer, Troposphere, and Lower Stratosphere Operations

Stratosphere-Troposphere (ST) radar wind profilers (RWPs) are typically built in the 400 – 500 MHz range (449 MHz in the USA) and have most often used coaxial-collinear (COCO) antenna elements and large monolithic transmitter systems. While the use of COCO elements can reduce the number of RF connections, it is difficult to control the antenna array sidelobe performance, the elements are large and fragile, the array has a narrow frequency bandwidth, and limited antenna array sizes are available. Similarly high power transmitters used for ST RWPs have been monolithic and unable to be easily reconfigured for lower powers. The lack of both an easily scalable antennas and transmitters has meant that 400 MHz band ST systems are unique (within their frequency and power-aperture product range), not easy to upgrade, and only have limited configurations.

A new RWP from DeTect, Inc. called the RAPTOR FBS, is scalable in both the antenna and the transmitter. The antenna uses Yagi-Uda elements, configured in a thinned array pattern. Each element uses a solid-state phase shifter, and is controlled in groups of 32. Because the array uses thinning to affect amplitude taper (and thus control sidelobes), the RF feed system is highly simplified and distributes power in either 32 or 64 element groups. Similarly the transmitter was constructed of 2 kW blocks, each with its own monitoring, cooling and DC power. This allows transmitter configurations from 2 kW through 16 kW and higher. These two features allow the system to be produced with various antenna sizes and transmitter sizes to best create a power-aperture product (or cost target) specifically to match the user's needs (e.g., boundary layer “quarter scale through full ST radars). In addition the straightforward scalability allows the system to be upgraded in the field. In 2010 this system was also chosen by the US National Weather Service (NWS) to replace the current systems used for the NOAA profiler Network (NPN). Systems are currently in production with to be installed in 2011. System features and data will be shown.