INTERFACE SPECIFICATIONS
SeaBat 8160
Operator‟s Manual
Page 87
October 6, 2011
Version 5
packets. Each fragment consists of one SNP1 header followed by many samples
of unsigned short magnitude data. Every Ethernet packet begins with either a
SNP0 or SNP1 header.
Below are the C structures for the SNP0 and SNP1 headers. The SNP0 header
is similar to a bathymetry header. All integers are Big-Endian (MSB first). All
structures are packed (no alignment gaps). Short has 16 bits. Long has 32 bits.
GainStart and GainEnd are currently set to zero and reserved for future use.
C.3.10.1 Header Formats
/* ID values for the SNP0 and SNP1 headers */
#define SNIPPET_ID_SNP0 0x534E5030
/* 'SNP0' */
#define SNIPPET_ID_SNP1 0x534E5031
/* 'SNP1' */
struct SNP0
/* ping header (there are BEAMS Snippets per ping) */
{
Unsigned long
ID;
/* identifier code */
unsigned short
HeaderSize;
/* header size, bytes */
unsigned short
DataSize;
/* data size following header, bytes */
unsigned long
PingNumber;
/* sequential ping number */
unsigned long
Seconds;
/* time since 00:00:00, 1-Jan-1970 */
unsigned long
Millisec;
unsigned short
Latency;
/* time from ping to output (milliseconds) */
unsigned short
SonarID[2];
/* least significant four bytes of Ethernet
address */
unsigned short
SonarModel;
/* coded model number of sonar */
unsigned short
Frequency;
/* sonar frequency (kHz) */
unsigned short
SSpeed;
/* programmed sound velocity (m/sec) */
unsigned short
SampleRate;
/* A/D sample rate (samples/sec) */
unsigned short
PingRate;
/* pings per second, 0.001Hz steps */
unsigned short
Range;
/* range setting (meters) */
unsigned short
Power;
/* power */
unsigned short
Gain;
/* gain (b15=auto, b14=TVG, b6..0=gain) */
unsigned short
PulseWidth;
/* transmit Pulse Width (microseconds) */
unsigned short
Spread;
/* TVG spreading, n*log(R), 0.25dB steps */
unsigned short
Absorp;
/* TVG absorption, dB/km, 1dB steps */
unsigned short
Proj;
/* b7 = steering, b4..0 = projector type */
unsigned short
ProjWidth;
/* transmit beam width along track, 0.1 deg
steps */
unsigned short
SpacingNum;
/* receiver beam spacing, numerator,
degrees */
unsigned short
SpacingDen;
/* receiver beam spacing, denominator */
short
ProjAngle;
/* projector steering,
degrees*PKT_STEER_RES */
unsigned short
MinRange;
/* range filter settings */
unsigned short
MaxRange;
unsigned short
MinDepth;
/* depth filter settings */
unsigned short
MaxDepth;
unsigned short
Filters;
/* enabled filters: b1=depth, b0=range */
struct
/* one byte containing eight status flags */
