Remote sensing Laser Airborne Depth Sounder (LADS) The Use of Satellite Data to Assist the Performance of an Airborne Sensor for Shallow Water Mapping Until recently all charting has been carried out with shipboard sensors, which although accurate are slow in terms of data collection. Many of the shipping charts which are currently in use are extremely old and inaccurate and badly need updating. The operational use of a Laser Airborne Depth Sounder (LADS), by the Royal Australian Navy (RAN) Hydrographic Section, has meant that the collection of such data is no longer such a time consuming and daunting task. The LADS is capable of sampling at a rate of fifty square kilometres per hour with a spatial resolution of 10 metres. There are limitations to using an airborne system. The laser is unable to penetrate cloud covered areas or turbid water, and therefore LADS use must coincide with relatively non-cloudy/non-turbid conditions. Figure 1   Figure 3   NOAA-AVHRR satellite images, received at the Australian Institute of Marine Science (Figure 1), were used to parametise cloud and turbidity conditions in target areas (Figure 2). - Figure 2 Information gained from these images was used to improve the success rate of LADS operations (Figure 3) by redirecting the LADS missions away from turbid and cloudy regions. This is a unique example of satellite remote sensing assisting the performance and accuracy of airborne remote sensing.   Specifications Sensor Package LADS (Laser Airborne Depth Sounder) AVHRR (Advanced Very High Resolution Radiometer) Platform Airborne (FOKKER F27-500) Space Borne (TIROS-N) Nominal Altitude 500 metres 800 kilometres Spatial Resolution 10 - 20 metres 1.1 kilometres Return Frequency Variable Twice each day and night Spectral Channels 2 (near infrared and green) 5 (visible, near infrared, middle infrared and 2 thermal infrared) Accuracy +/- 0.2 metres in 10 to 20 metre bins N/A   Computer generated image from Laser Airborne Depth Sounder (LADS)     RAN Fokker F27 ready for deployment Airborne measuring equipment aboard an RAN Fokker F27 Data processing ground-based equipment van Ground-based equipment van   For further information about the AIMS facility - contact: Mr. William Skirving, AIMS e-Mail: w.skirving@aims.gov.au Telephone: +61 (07) 47534357

December 18, 2008