StreamPro ADCP Operation Manual - global site

StreamPro ADCP Operation Manualcommon for bottom tracking measurements to lock onto a sediment layerthat is still moving, resulting in a bias to the bottom tracking velocity. Thisis especially important for river discharge measurements, where the vessel’snavigation must be substituted for the bottom track velocity to obtain accurateresults.------ N ------Navigator: Model name for the TRDI Doppler Velocity Log.Narrowband ADCP: An ADCP that uses narrowband processing.Narrowband Processing: Uses a single pulse per ping to measure velocity.The lack of coding in the pulse makes a narrowband measurement muchless precise, but it allows profiling over a longer range. Narrowband processinggenerally requires much larger ensembles to get a precise measurement.------ O ------Ocean Observer: Low frequency Phased Array ADCP for cabled deployment,usually from an oilrig.Ocean Surveyor: Low frequency Phased Array ADCP for vessel-mountedoperations.------ P ------Percent Good: A key quality control parameter, percent good indicateswhat fraction of the pings passed the various error thresholds. Each depthcell reports four values for percent good, and the meaning depends on thecoordinate frame. If data is collected in beam coordinates, then the fourpercent good values represent the percentage of the pings collected by eachbeam for that depth cell whose correlation exceeded a low correlationthreshold. In the other coordinate frames (ADCP, Ship and Earth Coordinates),the four Percent Good values represent (in order): 1) The percentageof good three beam solutions (one beam rejected); 2) The percentage ofgood transformations (error velocity threshold not exceeded); 3) The percentageof measurements where more than one beam was bad; and 4) Thepercentage of measurements with four beam solutions.Phase: An engineering measure of the propagation delay caused by radialmotion between scatterer and source. Phase is ambiguous in that it is cyclical(e.g. 10 º is the same phase as 370 º).Phased Array Transducer: A single, flat, multi-element transducer thatuses a TRDI proprietary technique to simultaneously form all four beams.Available phased array transducers are generally low frequency (38 kHz, 75kHz and 150 kHz) long range devices.page 106Teledyne RD Instruments