66 -- COMBINED GPS/IMU SHIPBOARD MOTION MEASUREMENT SYSTEM The purpose of this Request for Information (RFI) issued by the National Oceanic & Atmospheric Administration (NOAA), Environmental Technology Laboratory (ETL), in Boulder, CO, is to conduct market research on commercially available products relating to measurements of NOAA research ships' geographical position, velocity, and heading, as well as complete attitude information. ETL desires information on systems utilizing Global Position System (GPS) sensors combined with Inertial Measurement Unit (IMU) sensors to make continuous measurements of the following parameters: position on earth, true heading, true course, speed, time and date, pitch, roll, yaw, surge, sway, and heave. The combination of GPS and IMU sensors with "smart" processing (e.g., multi-stage Kalman filtering) should provide real-time high accuracy information for use in both post-processing of scientific data as well as for real-time control of data acquisition systems such as echosounders and radars. The combined GPS/IMU should also provide for data integrity validation and protection during brief periods of GPS dropout or other causes of invalid data. The GPS sensor cannot rely on coastal-based differential techniques (DGPS) as the NOAA ship will often be operating in the deep ocean. Multi-antenna attitude-finding GPS techniques are desired so that the IMU can be continuously validated and calibrated particularly with respect to heading, and also so the system can be initialized in a dynamic environment. The IMU should utilize new solid-state technologies to enable the unit to be relatively inexpensive, maintenance free, and highly reliable. The IMU should also be as free of mounting orientation as possible and be designed to be installed outside the interior of the ship where it will be exposed to tropical and arctic marine environments. The data rate for the system should be greater than 20 Hz and should utilize data propagation techniques to provide for less than 20 ms latency. The accuracy of the position information should be that of the Standard Position Service (SPS) GPS. The accuracy of the rotational measurements of heading, pitch, and roll should be at least plus or minus O.25 degrees. The accuracy of the translation measurements of surge, sway, and heave should be at least 0.1 m/s. The system must also provide Coordinated Universal Time (UTC) date and time information. Serious respondents representing commercially available products are invited to contact Scott McLaughlin, Electronics Engineer, at NOAA R/E/ET4, 325 Broadway, Boulder, CO 80303-3328, telephone (303)497-6473, e-mail smclaughlin@etl.noaa.gov. Submit responses by August 25, 1998. For strictly procedural questions regarding this RFI, contact David S. Groton, Contracting Officer, (303) 497-3107. It is possible, but not guaranteed, that there will be a procurement action in the future; however, there will be no contract awarded on the basis of this RFI. There will be no reimbursement for information submitted in response to this RFI. Posted 07/29/98 (W-SN230128).

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