EMdgmMRZ_def Struct Reference

#MRZ - Multibeam Raw Range and Depth datagram. The datagram also contains seabed image data. More...

#include <EMdgmFormat.h>

Collaboration diagram for EMdgmMRZ_def:

Data Fields
struct EMdgmHeader_def	header
struct EMdgmMpartition_def	partition
struct EMdgmMbody_def	cmnPart
struct EMdgmMRZ_pingInfo_def	pingInfo
struct EMdgmMRZ_txSectorInfo_def	sectorInfo [MAX_NUM_TX_PULSES]
struct EMdgmMRZ_rxInfo_def	rxInfo
struct EMdgmMRZ_extraDetClassInfo_def	extraDetClassInfo [MAX_EXTRA_DET_CLASSES]
struct EMdgmMRZ_sounding_def	sounding [MAX_NUM_BEAMS+MAX_EXTRA_DET]
int16_t	SIsample_desidB [MAX_SIDESCAN_SAMP]

Detailed Description

#MRZ - Multibeam Raw Range and Depth datagram. The datagram also contains seabed image data.

Datagram consists of several structs. The MRZ datagram replaces several old datagrams: raw range (N 78), depth (XYZ 88), seabed image (Y 89) datagram, quality factor (O 79) and runtime (R 52).

Depths points (x,y,z) are calculated in meters, georeferred to the position of the vessel reference point at the time of the first transmitted pulse of the ping. The depth point coordinates x and y are in the surface coordinate system (SCS), and are also given as delta latitude and delta longitude, referred to origo of the VCS/SCS, at the time of the midpoint of the first transmitted pulse of the ping (equals time used in the datagram header timestamp). See Coordinate systems for introduction to spatial reference points and coordinate systems. Reference points are also described in Reference points and offsets. Explanation of the xyz reference points is also illustrated in the figure below.

Depth point and reference systems

Definition at line 1217 of file EMdgmFormat.h.

Field Documentation

SIsample_desidB

int16_t SIsample_desidB[MAX_SIDESCAN_SAMP]

Seabed image sample amplitude (BS), in 0.1 dB steps. Seabed image data is raw beam sample data taken from the RX beams.

BS = 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.
BSoffset = User specified offset (in dB) per head, documented in the installation datagram (default G = 0.00)

Actual number of seabed image samples (SIsample_desidB) to be found by summing parameter SInumSamples in struct EMdgmMRZ_sounding_def for all beams.
The data samples are selected based on the bottom detection ranges. First sample for each beam is the one with the lowest range.
The centre sample from each beam, specified by EMdgmMRZ_sounding_def.SIcentreSample, is geo referenced (x, y, z data from the detections).

Definition at line 1227 of file EMdgmFormat.h.

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The documentation for this struct was generated from the following file:

• EMdgmFormat.h