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DOPPLER SPEED LOG Marine Speed and Distance Measuring Equipment (SDME) MODEL
DS-80
PRINTED IN JAPAN
C
Your Local Agent/Dealer 9-52, Ashihara-cho, Nishinomiya, Japan Te l e p h o n e : Te l e f a x :
0798-65-2111 0798-65-4200
A l l r ig h t s r e s e r v e d .
Printed in Japan
P U B . N o . S M E - 7 2 4 7 0 -A M AY AYA
DS-80
FIRST
E D IT I O N
:
OCT
2000
CONTENTS FEATURES………………………………………………… 1 PRINCIPLE………………………………………………… 2 EQUIPMENT LISTS ……………………………………… 3 SPECIFICATIONS ………………………………………… 5 1. SYSTEM CONFIGURATION ………………………….. 7 2. FUNCTION OF EACH UNIT …………………………... 8 3. POWER SUPPLY CIRCUIT ……………………………. 9 4. TRANSMISSION ………………………………………… 12 5. RECEIVING CIRCUIT ……………………………….….13 6. PARTS LOCATIONS ……………………………………..15 7. ADJUSTMENT/SETTINGS …………………………….. 20
7.1 Transducer Adjustment……………………………………20 7.2 Setting of Maximum Speed Range………..………………21 7.3 Setting for Analog Display……………………………….. 22 8. TROUBLSHOOTING…………………………………… 23
8.1 Diagnostics, Checking ID Program………………………. 23 8.2 Checking the Interconnection……………………………. 25 9. DIGITAL INTERFACE (IEC 61162-1)…………………. 26
MECHANICAL PARTS LIST …………………………
D-1
ELECTRICAL PARTS LIST ……………………………
E-1
SCHEMATIC DIAGRAM
Interconnection Diagram…………………………………….. S-1 Display Unit Schematic Diagram……………………………. S-2 Transceiver Unit Schematic Diagram…………………………S-3 Distribution Box Schematic Diagram……………………… Diagram……………………… S-4/S-5 Circuit Diagram of Transceiver Unit………………………S-6 to S-8 Circuit Diagram of Display Unit……………………………S Unit……………………………S-9/S-10 -9/S-10 Circuit Diagram of Distribution Box………………………S-1 Box………………………S-11 1 to S-15 Transducer…………………………………………………….S-16
FEATURES The FURUNO DS-80 displays ship’s speed relative to water, using the Doppler principle; ship’s speed is measured by detecting the Doppler shift frequency from the signal returned from the water-mass. The output is interfaced with ARPA, AIS, and other ship-borne equipment in IEC 61162-1 format. The main features of the DS-80 are simple operation. In most cases all that is required to display ship’s speed is to turn on the equipment. Pair-beam system effectively reduces error caused by pitching. The transducer assembly symmetrically emits two sonic beams, one fore and the other aft. By averaging the Doppler shift in both directions accurate speed data is available under rough sea conditions. Speed and distance information on the adjustable-contrast LCD display. Analog display, display, digital Indicator and digital distance indicator display optionally available. Complies with IMO Res. A.824(19) and IEC 61023: 1997.
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PRINCIPLE The doppler sonar measures ship's speed by using the principle of the Doppler effect, which defines that a signal emitted from a moving object is heard with its frequency shifted at stationary locations and the degree of the frequency shift is proportional to the speed of the moving object. For ease of understanding measurement measurement of ship's fore-aft speed is explained. The DS-80’s DS-80’s two-pair beam system is illustrated in the figure at right. Ultrasonic waves are emitted at an angle of relative θ to water line toward ship's fore and aft directions. If the ship's speed is V, V, the source of the ultrasonic wave (transducer) (t ransducer) approaches or goes away from the reflecting points on the seabed at a speed of Vcos θ. This relative motion causes the Doppler shift and the ultrasonic waves reflected at the seabed are received at frequencies of fo + fd and fo – fd by the transducer. A processor in the DS-80 computes the difference of fo + fd and fo – fd to extract only the Doppler shift factor fd. fo + fd – (fo – fd) = 2fd
Since the fd is theoretically given by fd = 2Vcosθ x fo/C (C: Sound velocity in water) and fo, C and θ are known, V can be calculated if the fd is given. fd = 2Vcosθ fo C
Note that the sound velocity in water changes with water temperature and water pressure but the change by water temperature is automatically compensated by using temperature sensor. V
θ
fo-fd
fo fd
V θ
V cosθ
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EQUIPMENT LISTS Standard supply Name Main Display Distribution Box
Transceiver Unit Transducer Unit Terminal Box Spare Parts
Installation Materials
Type DS-800 DS-801-100 DS-801-110 DS-801-115 DS-801-200 DS-801-220 DS-801-230 DS-810 DS-820 DS-802 SP65-00700
Code No. 000-029-046
Qty 1
1 1 1 1 set
SP65-00710
000-029-056
1 set
CP65-00900
000-029-047
1 set
1
Remarks 100 VAC 110 VAC 115 VAC 200 VAC 220 VAC 230 VAC
For 115 V, w/SP65-00701, SP65-00702, SP65-00601 For 230 V, w/SP65-00702, SP65-00702, SP65-00601 w/CP65-00901, CP65-00902, CP65-903
Optional equipment Digital Indicator (000-029-020) Name
Type
Code No.
Qty
Remarks
Digital Indicator
DS-830
Spare Parts
SP65-00601
002-889-730
1 set
Fuse
Accessories
FP65-00400
000-029-028
1 set
Installation Materials
CP65-00800
000-029-027
1 set
FP65-00401, FP65-00402, FP65-00403 CP65-00801, MJ-A7SPF-005-020, MJ-A6SPF-003-020
-
1
Remote Distance Indicator (000-029-022) Name Remote Indicator
Type
Distance DS-840
Code No. -
Qty
Remarks
1
Spare Parts
SP65-00601
002-889-730
1 set
Fuse
Accessories
FP65-00400
000-029-028
1 set
Installation Materials
CP65-00800
000-029-027
1 set
FP65-00401, FP65-00402, FP65-00403 CP65-00801, MJ-A7SPF-005-020, MJ-A6SPF-003-020
3
Optional equipment (con’t) Name Terminal Box Range Switch Box
Dimmer
Junction Box Kingston Seachest
Analog Display
Type DS-802 DS-389 MF-22R-1 MF-22R-2 MF22L-1100V MF22L-1200V MF22L-2100V MF22L-2200V CI-630 TFB-5000 (1) DS-850 DS-781 DS-782 DS-783 DS-784 DS-786 DS-773-A DS-761R-S DS-762R-S MF22A-4
Code No. 000-029-048 000-028-039 000-069-391 000-069-392 000-069-401
Qty 1 set 1 set 1 set 1 set 1 set
000-069-402
1 set for 230 V, flush mount
000-069-403
1 set for 115 V, bulkhead
000-069-404
1 set for 230 V, bulkhead
000-015-206 000-029-050 000-029-051 000-029-052 000-029-053 000-029-054 000-029-055 000-028-960 000-028-975 000-028-976 000-069-384
1 set 1 1 set 1 set 1 set 1 set 1 set 1 set
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Remarks w/CP65-00903 w/CP66-01000 Flush mount type Bulkhead type for 115 V, flush mount
w/CP66-00703
w/tightening handle Projection type Gate valve, projection type Flush mount, projection type Flush type Gate valve type -10 to +20 knots, flush mount 1 set -10 to +30 knots, flush mount -10 to +30 knots, bulkhead -10 to +30 knots, compact type
SPECIFICATIONS 1. GENERAL (1) Speed Range (2) Distance Run (3) Working Depth (4) Working Frequency (5) Speed Accuracy (6) Distance Accuracy
Fore-Aft: -10.0 to +40 knots through-the-water 0.00 to 999,999.99 nautical miles through-the-water Water depth greater than 3 m beneath the keel. 1.0 MHz 1.0% or 0.1 knots whichever is the greater 1.0% or 0.1 nm whichever is the greater
Note: Accuracy is subject to shallow water effects, to the effect of wind, current and tide, and sensor location. Any ultrasonic equipment having the same frequency may interfere with speed measurement. The Doppler Log transducer should be installed apart from the transducers of such kind of equipment.
2. DISPLAY UNIT (1) Display (2) Indication Ship's speed Distance run (3) Other Function
Character size 15 or 21 mm H on monochrome LCD Fore: ↑ **.* knots (+40.0 max) Aft: ↓ **.* knots (-10.0min) ******.** nm (999999.99 max) Diagnostic check
3. DIGITAL INTERFACE (1) Serial Signal Output: Input: (2) Analog Signal
2 port; VBW, VLW in IEC 61162-1 (NMEA 0183 Verl.5/2.0) 1 port; 1EC61162 (NMEAOI83Ver1.5/2.0) Speed signal for Analog display, 3 port -3.3 mA to 10 mA/-l0 to +30 kt, -3.3 to 10V/-10 to 30kt Analog current output: 1 port, analog voltage output: I port (3) Distance run output Contact closure each 0.005 nm, forward speed, 30 VDC: 0.2 A Pulse wideth: **ms Leading edge: **ms (4) System Check signal 1 port, 30 VDC: 0.2 A, default: closed
4. POWER SUPPLY (1) System Source (2) Rated Current
100/115/120/200/220/230 VAC (+/-10%), 1 phase, 50-60 Hz 115 V: 1.5 A max, 230 V: 0.7 A max.
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5. ENVIRONMENTAL CONDITION (lEC 60945) (1) Ambient Temperature 0 0 Analog display 0 C to +50 C 0 0 Others -15 C to +55 C 0 (2) Relative Humidity 95% at 40 C (3) Vibration +/-1 mm +/-10%, 2(5) to 13.2 Hz, 2 Maximum acceleration 7 m/s , 13.2 to 100 Hz (4) Category of Equipment Display Unit! Distance indicator / Transceiver Unit: For protected area, IPX5 Transducer: For submerged area, IPX8, 600 kPa Distributor / Terminal box: For protected area, IPX2
6. COATING COLOR (1) Display Unit (2) Distributor (3) Transceiver Unit (4) Terminal Box (5) Analog Display
Cover: Munsell 2.5GY5/1 .5 (light gray) Panel : N3.0 (gray) Munsell 2.5GY5/1 .5 (light gray) Munsell 2.5GY5/1 .5 (light gray) Munsell 2.5GY5/1 .5 (light gray) Munsell 2.5GY5/1 .5 (light gray)
7. COMPASS SAFE DISTANCE (1) Display Unit, Digital Indicator and Digital Distance Indicator Standard: 0.60 m, Steering: 2.10 m (2) Transceiver Unit Standard: 2.50 m, Steering: 1.40 m (3) Terminal Box, Distributor and Terminal Box Standard: 0.65 m, Steering: 0.45 m VALUES TENTATIVE
SAFETY PRECAUTION * There is no unit giving rise to a dose rate > 0.5 mrem/h at 50 mm. * There is no harmful radiation from the screen. * All units of this equipment comply with EMC requirements in lEC 60945.
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1. SYSTEM CONFIGURATION DISPLAY UNIT DS-800
TERMINAL BOX DS-802 DIMMER MF-22L-1/MF-22L-2 IEC 61162-1 Input Power ON SW Signal Distance Run Signal IEC 61162-1 Output
DISTRIBUTION BOX DS-801
DIMMER MF22L-1/MF22-2
JUNCTION BOX DS-802 JUNCTION BOX CI-630
TRANSCEIVER UNIT DS-810
DIGITAL DISPLAY DS-830 REMOTE DISTANCE INDICATOR DS-840
DIMMER MF-22L-1/MF-22-2
RANGE SWITCH BOX DS-389
115/230 VAC
ANALOG DISPLAY UNIT DS-762/DS-763 /MF-22A-4/MF-22A-9, and others
SHIP'S MAINS 115/230 VAC
: STANDARD SUPPLY
TRANSDUCER DS-820
: OPTIONAL SUPPLY : LOCAL SUPPLY
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2. FUNCTION OF EACH UNIT
DISPLAY UNIT (DS-800)
ICP board (65P6000) •
Displays the ship's speed and the distance run.
DISTRIBUTION BOX (DS-801) JPW board (65P6010) •
Distributes the ship's speed data with NMEA format
•
Outputs a analog ship's speed data for display unit.
•
Outputs a Log Pulse
•
Supplies the power for the optional display unit.
•
Supplies the powers for the transceiver unit
TRANSCEIVER UNIT (DS-810) KCP board (65P6020) •
Transmits and receives the signal
•
Calculates the ship's speed by processing the received signal
TRANSDUCER UNIT (DS-820) LTD board (65P6050) •
Matching board
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3. POWER SUPPLY CIRCUIT The DS-80 is shipped from the factory ready for connection to the ordered AC power supply specified when ordering. To connect to a different AC power supply, change the jumper wiring on the terminal TB5 in the Distribution Box and change the FUSE, as shown in Figure 3.1. Note: From 100 VAC to 200 VAC changing is not available.
Fuse
Terminal Board 100VAC 9 8 7
6
5
4
3
2 1
110VAC 9 8 7
6
5
4
3
2 1
120VAC 9 8 7
6
5 4
3
2 1
7
6
5 4
3
2 1
220VAC 9 8 7
6
5
4
3
2 1
230VAC 9 8 7
6
5 4
3
2 1
200VAC 9 8
Jumper wire
AC power supply and jumper wires on the terminal board in the distribution box
Distribution box, cover removed
AC ower su l and fuse 100/110/120VAC 3A(250V) 200/220/230VAC 3A(250V)
Note: Earlier production sets have 1A fuse. It is replace with 3A fuse if it is blown off.
Figure 3.1. Changing the jumper wiring
Power supply circuit in the Display unit and Distribution Box See the schematic diagram in Figure 3.2. Ship's Main is supplied to the step-down transformer T1 through the power switch S1, fuse F1 and AC filter FL1 in the Distribution Box. Since the power switch S1 keeps on, the 24VDC is always generated from the rectifier circuit composed by CR1/CR2/CR3/CR4, and supplied to the display unit as power supply. When the power key on the display unit is pressed, the output of Q3 (24VDC) activates the photo coupler U2, the relay K1 and K2 on the JPW board in the Distribution Box. Once the relay K1 and K2 become on, the 100VAC/0.1A is supplied to the DC regulator circuit on the JPW board and 100VAC/0.85A is supplied to the Transceiver Unit (DS810). Inspection of the JPW board (65P6010) Measuring Points +5VDC TP18 +15VDC TP19 and TP20(GND) -15VDC TP21 and TP20(GND)
Measured by Digital Multimeter Ditto Ditto
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Rating 4.75 to 5.25VDC 14.25 to 15.75VDC -14.25 to -15.75VDC
. x o B n o i t u b i r t s i D d n a t i n U y a l p s i D e h t n i t i u c r i c r e w o P
0 1 0 6 P 5 6 W P J
2 . 3 e r u g i F
t i n U y a l p s i D
0 0 0 6 P 5 6 P C I
x o B n o i t u b i r t s i D
10
Inspection of the ICP board (65P6000) Measuring Points 3VDC 5VDC 24VDC
TP19 TP20 TP3 and TP1
Measured by
Rate
Digital Multimeter Ditto Ditto
3.14 to 3.46VDC 4.75 to 5.25VDC 16 to 32VDC
Power circuit in the Transceiver Unit See the schematic diagram in Figure 3.3. The 100VAC is supplied from the Distribution Box, and applied to 12VDC, 5VDC and +B voltage regulator circuits on the KCP board.
KCP 65P6020
Figure 3.3 Power circuit in the Transceiver Unit
Inspection of the KCP board (65P6020) Measuring Points +B FUSE F1 +12V TP23 +5V TP24 +5VA TP25
Measured by Digital Multimeter Digital Multimeter Digital Multimeter Digital Multimeter
11
Rating 130 to 150VDC 11.4 to 12.6VDC 4.75 to 5.25VDC 4.75 to 5.25VDC
4. TRANSMISSION See the schematic diagram in Figure 4.1. The transmission pulse having a 1MHz carrier frequency is outputted from the CPU on the KCP board, it's pulse-length and repetition rate are 1ms and 150ms. The transmission pulse is sequentially applied to the buffer "Q3", driver circuit "Q6/Q5", and Power MOS FET amplifier Q2/Q7, then simultaneously outputs to the forward and after transducers through the transformer T5. The transmission output level must be 117 to 143Vpp as shown in Figure 4.2 .
Figure 4.1 Transmission circuit
Measuring point Forward output TB1: #4 and #5 After output TB1: #7 and #8 Figure 4.2
Waveform of the Transmission output at TB1.
12
5. RECEIVING CIRCUIT See the schematic diagram in the Figure 5.2. The received signals from the For./Aft. transducer are individually amplified by the each amplifier circuit "U201/U202 and U204/U205" on the KCP board, and then mixed with the carrier signal by the mixer "Q201/Q202" so as to convert the received frequency into 125kHz +/- f d (IF signal). The IF signals are further amplified by the logarithmic amplifier "U13 and U15", and converted into a square-waves by the comparator U14 and U16. The outputs of the U14 and the U16 are then sent to the CPU circuit where the doppler shifts are measured and calculate the ship's speed.
Inspection Check the waveforms at the test points TP5 and TP10. The waveform at each test point is as follows;
Transmission si nal
Echo
v
Noise level Signal level
Figure 5.1 Waveform at the Test Point TP5 and TP10
Note: The noise level should be lower than the "1.0 V" and higher than "0.5 V".
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r o t a r a p m o C
r o t a r a p m o C
r e i f i l p m A . g o L
r e i f i l p m A . g o L
r e i f i l p m A
r e i f i l p m A
r e t l i F
r e t l i F
0 1 P T / 5 P T
t i u c r i C g n i v i e c e R
r e x i M
r e x i M
r e t l i F
2 . 5 e r u g i F
r e t l i F
r e i f i l p m A
r o t a l l i c s O l a c o L
r e i f i l p m A
r e i f i l p m A
r e i f i l p m A
r e c d u r d a s w r n o a r F T
r e c u d r s e n t f a r A T
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6. PARTS LOCATIONS
Figure 6.1 Display unit , front view
Figure 6.2 Display Unit, rear view
15
FG(GND) ICP board (65P6000)
J2 J1
Figure 6.3 Display Unit, ICP board (65P600)
Transformer T1 AC. Plug
KCP board (65P6020)
Power Switch S1
TB2
Terminal TB1
Figure 6.4 Transceiver Unit (DS-810)
16
Terminal TB5
Transformer T1
JPW board (65P6010)
24V Regulator U1 Relay K1 Fuse F1
AC Filter inside
Power Switch S1
Terminal TB4
TB1
TB2
TB3
Figure 6.5 Distribution Box (DS-801)
17
TP25: +5V TP24: +5V(D)
TP22: DGND
TP16: +B
CR22
J3 CR21
FUSE: F1
TP21 S1
TP15
S2 TP3 TP1 TP4 TP2 J1
TP14 J5 TP7:SIG2 TP17:DGND
TP9:DGND TP26:AGND J2
TP16:VLOG2 TP6:SIG1 TP5:VLOG1
CR18 CR17 CR16 CR15
TP20:AGND TP19 TP18
J4 J6 TP23: +12V
TB1
Figure 6.6 KCP board (65P6020)
18
TP15
TP18
S2
U17
TP4
CR9 CR10
R100
R145 CR16 S3 JP8 JP6
TP21 TP20 TP19 TP23 R22 R36 R29 R40 S1 TP7 R96 R88
CR15 CR14 TP22 S4 TP14 ANAV CR21 TP13 ANAC TP16 TP12 TP17
Figure 6.7 JPW board (65P6010)
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7. ADJUSTMENT/SETTINGS 7.1 Transducer Adjustment Transducer mounted error, which causes incorrect speed value, can be compensated the main display through the menu (Range: -45 to +45 ). 1. Press the [MENU] key to display the main menu. °
°
MENU DISTANCE RUN DISPLAY CONTRAST DEMO SYSTEM MENU SYSTEM MENU 2
Figure 7.1.1 Main menu
2.
Select SYSTEM MENU and press the [ENT] key to display the system menu. SYSTEM MENU SHIP SPD AVG SPEED OFFSET TRACK DEPTH XDR OFFSET SPD DATA SELECT
15 SEC - 0.0% 2.0m -00 DOPPLER
Figure 7.1.2 System menu
3. 4.
Select XDR OFFSET and press the [ENT] key. Press !or" to select the digit or sign (+ or -) you want to change; press digit and +/-. For example, when there is +5 error enter “+05”. Press the [ENT] key. Press the [MENU] key twice to close the menu. °
5. 6.
20
# or $ to
select the
7.2 Setting of the Maximum Speed Range Change the maximum range of the connected analog display by setting of DIP switch S2 in the distribution box. Maximum speed S2
20 kt #1: ON Others: OFF
30 kt All: OFF
JPW Board
40 kt #2: ON Others: OFF
S2 (Default setting: all OFF)
Distribution box DS-801, inside view
Figure 7.2 Distribution Box, inside view
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7.3 Setting for Analog Display When the analog indicator is connected, synchronize the speed displays of DS-80 main display unit and analog display as follows.
7.3.1 Connected to TB2 ANA1 (analog 1) 1. Set at 0 knot on the DEMO display, and then adjust R29 in the distribution box so as that the analog display shows 0 knot.
2. Set at 30 knots on the DEMO display, and then adjust R40 in the distribution box so as that the analog display shows 30 knots.
7.3.2 Connected to TB2 ANA2 (analog 2) 1. Set at 0 knot on the DEMO display, and then adjust R27 in the distribution box so as that the analog display shows 0 knot.
2. Set at 30 knots on the DEMO display, and then adjust R36 in the distribution box so as that the analog display shows 30 knots.
7.3.3 Connected to TB2 ANAV (analog voltage signal) 1. Set at 0 knot on the DEMO display, and then adjust R100 in the distribution box so as that the analog display shows 0 knot.
2. Set at 30 knots on the DEMO display, and then adjust R145 in the distribution box so as that the analog display shows 30 knots.
7.3.4 Connected to TB2 ANAC (analog current signal) 1. Set at -10 knots on the DEMO display, and then adjust R87 in the distribution box so as that the current is 4 mA.
2. Set at +30 knots on the DEMO display, and then adjust R96 in the distribution box so as that the current is 20 mA.
Set to OFF.
R36 R27 R29 R40
R87
ON OFF
Power switch: Upper Figure 7.3 Distribution Box Distribution box DS-801
22
R100 R145 R96
8. TROUBLSHOOTING 8.1 Diagnostics, Checking ID Program The diagnostic facility checks the ROM, RAM, SIO and displays program ID. 1. Press the [MENU] key to open the menu. 2. Select SYSTEM MENU2 and press the [ENT] key. SYSTEM MENU2 TEST
DIMMER INTERNAL /LANG. ENGLISH
3. Press the [ENT] key. The following display appears. TEST START ? (STOP: PWR OFF) ARE YOU SURE ? YES NO
4. Press the [ENT] key to start the test. In a few moments your display should look something like the one shown below. The ROM, RAM and SIO (if special connector is connected) are checked for proper operation and the results shown as OK or NG (No Good). For NG, contact your dealer for advice. “PUSH KEY” is highlighted, prompting you to check the controls. Operate any control (except the [POWER] switch) within five seconds of seeing PUSH KEY highlighted. The name of the activated control appears on screen if it is operating normally. Note that if no control is operated within five seconds the equipment automatically begins checking the LCD. Name of control operated appears here. SELF TEST ROM RAM SIO*
: OK : OK : OK
PUSH KEY
No. of times test consecutively executed.
(STOP: PWR OFF) CNT: 006 65-5-0100-0XX
XX = Program ver. no. * Requires special connector to test. This location is blank when the connector is not connected.
23
5.
The equipment automatically checks the LCD, displaying the following in order. ALL ON 2 SEC. ALL OFF 3 SEC.
6.
The test repeats itself. To escape from the test, turn the power off and on again.
24
8.2 Checking the Interconnection The equipment do the following to confirm if the doppler speed signal is being output correctly. 1. Press the [MENU] key to display the main menu. 2. Select DEMO, and press the [ENT] key to display the demo menu.
DEMO SPEED +10.0 kt
DATA OUTPUT
OFF
DEMO MODE menu
3. 4. 5.
6. 7. 8. 9. 10. 11.
Select SPEED. Press the [ENT] key. Use the cursor pad to enter the speed value desired. !": Change value, +/#$: Change digit Press the [ENT] key. Select DATA OUTPUT and press the [ENT] key. Press ! to select ON and press the [ENT] key. Press the [DISP] key. Confirm the value displayed is the same as it entered at step 5. Confirm the same as speed is shown on external equipment (radar, GPS, etc.). Select OFF at DATA OUTPUT, and press the [ENTER] key.
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9. DIGITAL INTERFACE (IEC 61162-1) 1. I/O Sentences Input GGA, VTG
Output VBW, VLW
2. Sentence Description GGA - Global positioning system (GPS) fix data
Time, position and fix related data for a GPS receiver. Differential reference station ID, 0000-1023* Age of differential GPS data* Units of geoidal separation, m* Geoidal separation * Units of antenna altitude, m* Antenna altitude above/below mean sea level (geoid)* Horizontal dilution of precision* $--GGA, hhmmss.ss. 1111.11, a, yyyyy.yy, a, x, xx, x.x, x.x, M, x.x, M, x.x, xxxx*hh
Number of satellites in use, 11-12, may be different from the number in view* GPS quality indicator (note 1) Longitude - E/W* Latitude - N/S* UTC of position* NOTES
1
GPS quality indicator:
0 = fix not available or invalid 1 = GPS SPS mode, fix valid 2 = differential GPS, SPS mode, fix valid 3 = GPS PPS mode GPS fix valid
* Not used.
26
VTG - Course over ground and ground speed
The actual course and speed relative to the ground. $--VTG, x.x, T, x.x, M, x.x, N, x.x, K*hh
Speed, km/h* Speed, knots Course degrees magnetic* Course degrees true* *: Not used. VBW - Dual ground/water speed
Water-referenced and ground-referenced speed data. $--VBW, x.x, x.x, A, x.x, x.x, A, x.x, A, x.x, A *hh * No use
Status, stern ground speed* Stern transverse ground speed* Status, stern water speed* Stern transverse water speed* Status, ground speed* Transverse ground speed* Longitudinal ground speed* Status, water speed* Transverse water speed* Longitudinal water speed1 , knots NOTES
1. Longitudinal speed: “-” astern. * Not used.
VLW - Distance travelled through the water
The distance travelled, relative to the water. S--VLW, x.x, N, x.x, N hh Distance since reset, nautical miles Total cumulative distance, nautical miles
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