Quality Control

All instruments are carefully checked before takeoff. Also the state of magnetic field is checked to ensure that it is inside given limits. During the flight a program checks the data of instruments and gives an alarm signal to the operator if there is any technical problem found. Also the main components are plotted on the screen to give continuos feedback. Beforehand set upper and lower limits of radio altimeter give alarm if current altitude is out of limits. A navigation program gives the perpendicular distance to the theoretical flight line and also distance to the end of that flight line.After the flight the data is checked immediately to ensure high data quality and proper operation of instruments. The quality control is done mainly by OASIS Montaj software package. All main components including altitude, barometer and temperature are checked carefully. Proper functioning of each component, magnitude of noise level, drifts etc. are observed. Also a new GEOSOFT airborne QC toolkit for quality control will be utilized.After every flight differential correction is made to the GPS data using post-processing software.  This software gives positioning accuracy (RMS) as one of its outputs. It also shows how many satellites there have been and gives figures that tell about the satellite geometry. This same software package can be used in advance before the flight to see how many satellites there will be in near future. Number of satellites and dilution of precision are presented in profiles. At least 8 satellites are visible all the time because also GLONASS satellites can be utilized. There are no peaks in the DOP profile, which tells that the accuracy will be very stable and good also because the value is very low all the time.In-house made program is used to plot the flight path over the flight lines. We use this same program also to crop the continuos data into flight line data. A GPS receiver is checked in real time as it is used together with our special navigation program for navigating. Also if there are e.g. gaps, it is noticed immediately. The line spacing and sample interval is checked with OASIS Airborne QC to find out those parts of flight line which are out of limits. Also OASIS Montaj’s interpolation and mapping will be used and with proper parameters given in interpolation a white gap will be seen on the map, if line separation is too large. The speed of aeroplane is calculated for each line and it can be checked also sample by sample with OASIS.The flight altitude is checked to find out those parts of a line which are out of tolerances with QC. And OASIS Montaj can be used to verify this by plotting a three colour map, where green colour presents proper altitudes, red one altitudes too high and blue one altitudes too low.The magnetic base station data will be processed with in-house made programs. Magnetic reference field plots will be made after every flight in order to check that the limit for diurnal variation is not exceeded. Also manmade noise can be seen from this plot if there is any. The state of magnetic field is checked before any flight. The compensation quality is determined by calculating FOM. The quality of magnetometer is controlled by means of OASIS airborne quality control package QC.An average radiometric spectra and the main energy windows are plotted from each flight line in order to check spectral drift during the course of a flight.