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EM datagrams on *.kmall format
Reg. nr. 410224 rev J
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EM datagrams on *.kmall format
Reg. nr. 410224 rev J
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#MRZ - Data for each sounding, e.g. XYZ, reflectivity, two way travel time etc. More...
#include <EMdgmFormat.h>
#MRZ - Data for each sounding, e.g. XYZ, reflectivity, two way travel time etc.
Also contains information necessary to read seabed image following this datablock (number of samples in SI etc.). To be entered in loop (numSoundingsMaxMain + numExtraDetections) times.
Definition at line 1057 of file EMdgmFormat.h.
| uint16_t soundingIndex |
Sounding index. Cross reference for seabed image. Valid range: 0 to (numSoundingsMaxMain+numExtraDetections)-1, i.e. 0 - (Nrx+Nd)-1.
Definition at line 1060 of file EMdgmFormat.h.
| uint8_t txSectorNumb |
Transmitting sector number. Valid range: 0-(Ntx-1), where Ntx is numTxSectors.
Definition at line 1061 of file EMdgmFormat.h.
| uint8_t detectionType |
Bottom detection type. Normal bottom detection, extra detection, or rejected.
0 = normal detection
1 = extra detection
2 = rejected detection For detectionType 2 the range in is estimated. The estimated range is a extrapolated or interpolated using valid neighbor detections. The estimated range has been used to fill in amplitude samples in the seabed image datagram.
Definition at line 1065 of file EMdgmFormat.h.
| uint8_t detectionMethod |
Method for determining bottom detection, e.g. amplitude or phase.
0 = no valid detection
1 = amplitude detection
2 = phase detection
3-15 for future use.
Definition at line 1067 of file EMdgmFormat.h.
| uint8_t rejectionInfo1 |
For Kongsberg use.
Definition at line 1068 of file EMdgmFormat.h.
| uint8_t rejectionInfo2 |
For Kongsberg use.
Definition at line 1069 of file EMdgmFormat.h.
| uint8_t postProcessingInfo |
For Kongsberg use.
Definition at line 1070 of file EMdgmFormat.h.
| uint8_t detectionClass |
Only used by extra detections. Detection class based on detected range. Detection class 1 to 7 corresponds to value 0 to 6. If the value is between 100 and 106, the class is disabled by the operator. If the value is 107, the detections are outside the treshhold limits.
Definition at line 1071 of file EMdgmFormat.h.
| uint8_t detectionConfidenceLevel |
Detection confidence level.
Definition at line 1072 of file EMdgmFormat.h.
| uint16_t padding |
Byte alignment.
Definition at line 1073 of file EMdgmFormat.h.
| float rangeFactor |
Unit %. rangeFactor = 100 if main detection.
Definition at line 1074 of file EMdgmFormat.h.
| float qualityFactor |
Estimated standard deviation as % of the detected depth. Quality Factor (QF) is calculated from IFREMER Quality Factor (IFQ):
QF=Est(dz)/z=100*10^-IQF
Definition at line 1075 of file EMdgmFormat.h.
| float detectionUncertaintyVer_m |
Vertical uncertainty, based on quality factor (QF, qualityFactor).
Definition at line 1076 of file EMdgmFormat.h.
| float detectionUncertaintyHor_m |
Horizontal uncertainty, based on quality factor (QF, qualityFactor).
Definition at line 1077 of file EMdgmFormat.h.
| float detectionWindowLength_sec |
Detection window length. Unit second. Sample data range used in final detection.
Definition at line 1078 of file EMdgmFormat.h.
| float echoLength_sec |
Measured echo length. Unit second.
Definition at line 1079 of file EMdgmFormat.h.
| uint16_t WCBeamNumb |
Water column beam number. Info for plotting soundings together with water column data.
Definition at line 1084 of file EMdgmFormat.h.
| uint16_t WCrange_samples |
Water column range. Range of bottom detection, in samples.
Definition at line 1085 of file EMdgmFormat.h.
| float WCNomBeamAngleAcross_deg |
Water column nominal beam angle across. Re vertical.
Definition at line 1086 of file EMdgmFormat.h.
| float meanAbsCoeff_dBPerkm |
Mean absorption coefficient, alfa. Used for TVG calculations. Value as used. Unit dB/km.
Definition at line 1091 of file EMdgmFormat.h.
| float reflectivity1_dB |
Beam intensity (BS1) with traditional KM TVG correcting for the insonified area for a flat bottom, Lamberts law and normal incidence suppression.
BS1 = EL - SL - M + TVG + BSoffset
Where,
EL = Received echo level (not recorded in datagram)
SL = EMdgmMRZ_sounding_def.sourceLevelApplied_dB
M = EMdgmMRZ_sounding_def.receiverSensitivityApplied_dB
TVG = EMdgmMRZ_sounding_def.TVG_dB if Lamberts law is selected by the user. The Lamberts Law setting is stored in the runtime datagram. If Lamberts law is off, this TVG correction is not available.
BSoffset = User specified offset (in dB) per head, documented in the installation datagram (default G = 0.00)
BS1 is equal to the average amplitude of the seabed image samples for the sounding when Lamberts law is selected.
Definition at line 1092 of file EMdgmFormat.h.
| float reflectivity2_dB |
Alternative beam intensity (BS2), using simplified TVG similar to TVG in #MWC EMdgmMWCrxInfo_def.
BS2 = EL - SL - M + TVG + BSoffset + OFS
Note that to get the intended display value for BS2, the offset (OFS) needs to be substracted from BS2 (BS2 - OFS)
Where,
EL = Received echo level (not recorded in datagram)
SL = EMdgmMRZ_sounding_def.sourceLevelApplied_dB
M = EMdgmMRZ_sounding_def.receiverSensitivityApplied_dB
TVG = X log R + 2 alpha R + A
X = EMdgmMWCrxInfo_def.TVGfunctionApplied, common to all beams.
alpha = EMdgmMRZ_sounding_def.meanAbsCoeff_dBPerkm, given for each beam.
BSoffset = User specified offset (in dB) per head, documented in the installation datagram (default G = 0.00)
OFS = EMdgmMWCrxInfo_def.TVGoffset_dB (normally set to 30 dB) is the same user set offset that is used due to the 8 bit WCD resolution. Also available in runtime datagram, only stored if the water column logging is active.
A = 10 log (OmegaTX * OmegaRX/cos(B)), simplified area correction.
B = EMdgmMRZ_sounding_def.beamAngleReRx_deg
OmegaTX and OmegaRX are the TX and RX -3 dB opening angles in radians.
The opening angles are the nominal angles (like 1 x 2 degrees) corrected for the actual sector frequency.
Nominal frequency is 400 kHz for EM 2040, 100 kHz for EM 712, 30 kHz for EM 304, 12 kHz for EM 124.
Example EM 712: 2 degree TX at 40 kHz: OmegaTX = radians(2 deg * 100kHz/40kHz). Actual sound velocity is not corrected for here.
Nominal OmegaTX and OmegaRX are stored in EMdgmMRZ_pingInfo_def.transmitArraySizeUsed_deg and EMdgmMRZ_pingInfo_def.receiveArraySizeUsed_deg.
For reflectivity2, Lamberts law and normal incidence suppression is not applied.
Definition at line 1105 of file EMdgmFormat.h.
| float receiverSensitivityApplied_dB |
Receiver sensitivity (M), in dB, compensated for RX beampattern along and across at actual transmit frequency at current vessel attitude.
Definition at line 1130 of file EMdgmFormat.h.
| float sourceLevelApplied_dB |
Source level (SL) applied (dB):
SL = SLnom + SLcorr + BScalibration_dB
Where,
SLnom = EMdgmMRZ_txSectorInfo_def.txNominalSourceLevel_dB, nominal maximum SL recorded per TX sector.
SLcorr = SL correction relative to nominal TX power based on measured high voltage power level and any use of digital power control, and compensated for TX beampattern at actual transmit frequency at current vessel attitude
BScalibration_dB = EMdgmMRZ_sounding_def.BScalibration_dB
Definition at line 1131 of file EMdgmFormat.h.
| float BScalibration_dB |
Backscatter (BScorr) calibration offset applied (default = 0 dB). From calibration file in #FCF datagram EMdgmFCF_def at actual transmit frequency and current vessel attitude.
Definition at line 1141 of file EMdgmFormat.h.
| float TVG_dB |
Time Varying Gain (TVG) that is applied for the seabed image samples (constant per sounding)
TVG = 40 log R - 10 log A + 2 alpha R + L
Where the L term represents KM Lamberts law and normal incidence suppression.
Definition at line 1143 of file EMdgmFormat.h.
| float beamAngleReRx_deg |
Angle relative to the RX transducer array, except for ME70, where the angles are relative to the horizontal plane.
Definition at line 1154 of file EMdgmFormat.h.
| float beamAngleCorrection_deg |
Applied beam pointing angle correction.
Definition at line 1155 of file EMdgmFormat.h.
| float twoWayTravelTime_sec |
Two way travel time (also called range). Unit second.
Definition at line 1156 of file EMdgmFormat.h.
| float twoWayTravelTimeCorrection_sec |
Applied two way travel time correction. Unit second.
Definition at line 1157 of file EMdgmFormat.h.
| float deltaLatitude_deg |
Distance from vessel reference point at time of first tx pulse in ping, to depth point. Measured in the surface coordinate system (SCS), see Coordinate systems for definition.
Unit decimal degrees.
Definition at line 1162 of file EMdgmFormat.h.
| float deltaLongitude_deg |
Distance from vessel reference point at time of first tx pulse in ping, to depth point. Measured in the surface coordinate system (SCS), see Coordinate systems for definition.
Unit decimal degree.
Definition at line 1164 of file EMdgmFormat.h.
| float z_reRefPoint_m |
Vertical distance z. Distance from vessel reference point at time of first tx pulse in ping, to depth point. Measured in the surface coordinate system (SCS), see Coordinate systems for definition.
Definition at line 1166 of file EMdgmFormat.h.
| float y_reRefPoint_m |
Horizontal distance y. Distance from vessel reference point at time of first tx pulse in ping, to depth point. Measured in the surface coordinate system (SCS), see Coordinate systems for definition.
Definition at line 1168 of file EMdgmFormat.h.
| float x_reRefPoint_m |
Horizontal distance x. Distance from vessel reference point at time of first tx pulse in ping, to depth point. Measured in the surface coordinate system (SCS), see Coordinate systems for definition.
Definition at line 1170 of file EMdgmFormat.h.
| float beamIncAngleAdj_deg |
Beam incidence angle adjustment (IBA) unit degree.
Definition at line 1173 of file EMdgmFormat.h.
| uint16_t realTimeCleanInfo |
For future use.
Definition at line 1174 of file EMdgmFormat.h.
| uint16_t SIstartRange_samples |
Seabed image start range, in sample number from transducer. Valid only for the current beam.
Definition at line 1179 of file EMdgmFormat.h.
| uint16_t SIcentreSample |
Seabed image. Number of the centre seabed image sample for the current beam.
Definition at line 1180 of file EMdgmFormat.h.
| uint16_t SInumSamples |
Seabed image. Number of range samples from the current beam, used to form the seabed image.
Definition at line 1181 of file EMdgmFormat.h.
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