Hemisphere GPS Crescent V110 - DGPS + Beacon - User Manual

Supplemental Sensors Common Commands and Messages
Crescent V100 Series
Quick Reference Guide
(Part Number 875-0185-000 Rev. A1)
A tilt sensor and gyro are integrated in the Crescent V100/
V110. The user can turn either on or off. However, the
system’s performance is optimized with both on.
GYRO AID TILT AID
Purpose Smooth rate of turn:
-Provides alternate
source of heading for
up to 3 minutes
when GPS lock is lost
-Shortens
heading
reacquisition
time
-Smooths rate of
heading
-Reduces startup
and
reacquisition
times for
obtaining
heading
Calibration
Procedure
Will self-calibrate after
several minutes
To manually calibrate:
-After heading is
computed
-$JATT,GYROAID,YES
-Spin Vector for 1
minute at less than
15
o
per second
-Leave unit stationary
for 4 minutes
**It is not necessary
to recalibrate with
standard use because
the gyro selects the
calibration.
Precalibrated
during
manufacture
To recalibrate:
-Ensure Vector is
level
-$JATT,TILTCAL
Differential Commands
$JDIFF Differential mode
$JWAASPRN Configure for specific SBAS PRN numbers
$JGEO Query for current location and satellites
$JASC,D1 Request SBAS diagnostic information
$GPMSK Tune beacon to specific frequency
Serial Port Setting Commands
$JBAUD RS-232C, RS-422 (output) communication rate
NMEA Messages
$GPGGA GPS fix data
$GPGLL Geographic position - lat/long
$GPGSA GNSS DOP and active satellites
$GPGSV GNSS satellites in view
$GPVTG COG and ground speed
$GPZDA Time and date
$GPHDG Provides magnetic deviation and variation for
calculating magnetic or true heading
$GPHDT RTK-derived GPS heading
$GPROT RTK-derived GPS Rate of Turn
$PCSI,1 Beacon status
$PSAT,HPR Heading, pitch/role and time in single message
$GPHDM Magnetic heading (based on RTK-derived GPS and
magnetic declination)
$J4STRING Output GPGGA, GPVTG, GPGSA and GPZDA (1 Hz max)
Heading Parameter
$JATT,TILTAID Enable/disable accelerometer,
pre-calibrated
$JATT,TILTCAL Calibrate accelerometer
$JATT,GYROAID Enable/disable gyro
$JATT,LEVEL Enable/disable level operation
$JATT,HTAU Set/query heading time constant (0.0 to 3600.0 sec)
$JATT,PTAU Set/query pitch time constant (0.0 to 3600.0 sec)
$JATT,HRTAU Set/query heading rate time constant (0.0 to 3600.0 sec)
$JATT,COGTAU Set/query COG time constant (0.0 to 3600.0 sec)
$JATT,SPDTAU Set/query speed time constant (0.0 to 3600.0 sec)
$JATT,HBIAS Set/query heading bias (-180.0° to +180.0°)
$JATT,PBIAS Set/query pitch/roll bias (-15.0° to +15.0°)
$JATT,NEGTILT Enable/disable negative tilt
$JATT,ROLL Configure for roll or pitch
$JATT,NMEAHE Changes the HDT, ROT, HDG and HDM message
headers between GP and HE (or HC)
Crescent V100 - DGPS
Crescent V110 - DGPS + Beacon
www.hemispheregps.com

Summary

Supplemental Sensors

Gyro Aid

Provides alternate heading source when GPS lock is lost and shortens heading reacquisition time.

Tilt Aid

Smooths rate of heading and reduces startup/reacquisition times for obtaining heading.

Calibration Procedure

Details self-calibration and manual calibration steps for heading and tilt sensors.

Common Commands and Messages

Differential and Serial Port Commands

Commands for differential mode, SBAS PRNs, and serial port settings like baud rate.

NMEA Message Types

Lists common NMEA messages for position, velocity, and satellite data.

Heading and Tilt Configuration

Commands to configure heading, tilt aid, gyro aid, level operation, and time constants.

Installation Location

Mounting Considerations

Choosing a location with a clear sky view, away from interference, and near power.

Pitch and Roll Mounting

Instructions for mounting parallel to boat axis for heading/pitch and perpendicular for heading/roll.

Wiring Interface and Configuration

Wiring Details

Information on cable part numbers, baud rates, NMEA messages, and wire connections.

Serial Port Connection (DB9)

Pinout configurations for DB9 female sockets for RS-232 and RS-422 interfaces.

Configuration Settings

Steps for setting baud rate, configuring NMEA messages, and inputting bias values.

Hemisphere GPS Crescent V110 - DGPS + Beacon Specifications

General

Impedance	50 Ohms
Type	DGPS + Beacon
Frequency	1575.42 MHz
Frequency Range	283.5-325 kHz (Beacon), 1575.42 MHz (L1)
Channels	12
Horizontal Accuracy	< 0.5 m 95% of the time
Update Rate	1 Hz
Operating Temperature	-30°C to +70°C
Gain	26 dB
VSWR	< 2:1
Polarization	Right Hand Circular (RHCP)
Connector Type	TNC