StreamPro ADCP Operation Manual - global site

StreamPro ADCP Operation ManualDegaussing: Technique used to remove the magnetic field from TRDI batterypacks before installation, done to minimize any effects the batterieswill have on the magnetic compass.Depth Cell (Bin): A measurement within a profile, generally equivalent to asingle-point current meter on a mooring.Depth Cell Mapping (Bin Mapping): When the ADCP is tilted; the measurementstaken at equal distances along each beam are no longer in thesame horizontal layer of water. For example, in the image below the tiltedADCP bins do not line up horizontally, they are offset by one bin. In thiscase the tilted ADCP will offset the bins on the “right” beam by one bin inorder to line them up horizontally with the bins on the “left” beam beforecombining the measurements to compute the velocity.DGPS: Differential Global Positioning SystemDifferential Global Positioning System (DGPS): Satellite-based navigationaid for precise measurement of location. When the bottom is out ofrange or moving, calculating the distance between DGPS position fixes anddividing by the time between those fixes can be used to measure the platformvelocity.Direct-Reading ADCP: An ADCP intended for real-time operation. Direct-ReadingADCPs do not have internal batteries or an internal recorder.Discharge: The total flow through a section of a river. Rio Grande ADCPsobtain discharge measurements by transecting the river to measure watervelocities, boat velocity, and the cross sectional area of the river and combiningthese measurements with estimates for the flow in the areas that cannot be measured (edge estimates, bottom discharge and top discharge).Distance Made Good: When measuring transects of data with a movingplatform, this is a measure of the actual distance between the platform andthe start point (i.e. variations in course track are removed).Doppler Shift: Named for Johann Doppler (1803-1853), the German physicistwho first predicted it: it is the shift in frequency caused by radial motionbetween a source and an observer. Specifically, f D = f S (v/c): Where Dis the Doppler-shifted frequency, f S is the source frequency, v is the relativevelocity between source and observer, and c is the speed of sound.page 102Teledyne RD Instruments