New Zealand: Land Information New Zealand (LINZ) observed that to combine gravity measurements with LiDAR is not feasible. So, the LINZ preferred to go ahead with the request for proposals (RFP) for the ‘Multi-Sensor Airborne Platform Project’ (M-SAP), according to Stuart Caie, Senior Hydrographic Surveyor at LINZ.
Earlier, the LINZ geodetic team wanted to fly some gravity measurement tools over Christchurch as a pilot scheme to improving the accuracy of the national geoid model and later on, to develop the RFP for the M-SAP.
Caie explained in his blog, “During preparing the RFP, it became clear that the two systems have different requirements for data collection and when we started the evaluation it was obviously not that simple to provide two systems on one platform.”
Caie added, “It is possible, as one of the providers found out, but a bit cramped onboard the plane. Nonetheless, they thanked us for giving them a challenge! However, with the additional cost, time and differing acquisition requirements, it was not to be so we had to revert to plan A – fly LiDAR only.”
“The idea for LINZ contracting the collection of some bathymetric LiDAR data came about for a number of reasons; to measure the performance of the latest Airborne Laser Bathymetry (ALB) systems; to collect data in Wellington Harbour as part of the Common Dataset for the Shallow Survey conference (SS2012) www.shallowsurvey2012.org in Feb; and to see if we could combine gravity measurements with LiDAR on one platform to save costs,” continued Caie.
Fugro LADS (www.fugrolads.com) were awarded the LiDAR work and are due to start in mid December.
The survey of Wellington Harbour will form part of the Common Dataset for the SS2012 conference, whilst the survey of the Abel Tasman coast should give us a good dataset in the nearshore environment. Both surveys will allow us to assess the system and do a comparison for target detection of known underwater hazards to determine position, least depth and extent – which have been previously surveyed to hydro charting standards with traditional sonar – single beam/side scan sonar and multibeam systems – from waterborne craft. LINZ last used LiDAR technology back in the late ’90’s, so this will give an up-to-date understanding and appreciation of the performance of the latest system which one can use to plan future hydrographic survey programme. If the project becomes successful, LINZ can potentially use LiDAR to achieve coverage of large areas and aid investigation of hazards/channels, then use surface craft with acoustics to survey the critical areas to the highest standards for safety of navigation charting. The LiDAR data will be available to delegates of the Shallow Survey conference and anybody else – they just need to pay for the 1Tb hard drive. This would also be served up through the LINZ Data Service.
Source: www.geospatial.govt.nz
