engleski

Integration of Position and Orientation System and Hyperspectral Line Scanner

As a requirement for geocoding of raw hyperspectral line scan imaging data, the exterior orientation data set need to be obtained, especially in all-parametric geocoding proc-esses. Application such those defined within recent technologic project “ System for the Mul-tisensor Airborne Reconnaissance and Surveillance in the Crisis Situations and the Environment Protection“ , supported by Croatian Ministry of Science, Education and Sports, highlighted the need for position orientation system capable to measure and record inertial orientation and GPS position data at high frequency. Integration of the PGP imaging spectrograph (pushbroom scan-ner) system and Position and Orientation System (POS) was requested due to geocoding of raw data cube produced by pushbroom scanner. Several approaches were examined and one pre-sented here was chosen. Integration of hyperspectral imaging scanner, acquisition PC system and POS has been achieved by sharing reference PC clock time as common platform. In this digital interface configuration, PC clock is continuously updated and corrected by GPS UTC time ex-ternally provided by 5Hz GPS data and 1PPS signal. Thereafter, both the control and acquisition timing of hyperspectral imaging sensor and POS are referenced to PC GPS time. The impact of time synchronisation on imaging capabilities and spatial accuracy of such system will be dis- cussed. Position and Orientation System is based on iMAR iVRU-RSSC, the GPS coupled MEMS based Inertial Reference Unit, providing Roll, Pitch, Yaw, GPS Latitude, GPS Longitude and GPS Altitude data at maximum frequency of 200Hz, according to general requirement for line imaging mode utilization of hyperspectral pushbroom scanner, which states that read-out frequency of Inertial Measurement Unit (IMU) should be at least of those of scanner imaging frequency, implying that at least one set of mentioned orientation and position data for each line scan need to be available. The spatial and dynamic characteristics of chosen POS fulfils all high precision hyperspectral imaging application requirements based on ImSpectror V9 pushbroom scanner which is currently in use, as far as future high precision- high frequency electro-optical sensor requirements.

Hybrid INS/GPS; Pushbroom Scanner; Direct Georeferencing

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