Interfacing Radar and GPS

[Gary]

I recently bought a 1995 320 Albemarle Express Fisherman. It has a Furuno
1830 Radar and a Garmin 220 GPS. In reading through the manuals for these
pieces of equipment, I have noticed that it's possible to connect a GPS to
the radar and it will display some nav information on the Radar unit as well
as having the ability to plot the speed and direction of various targets on
the radar.

Is this simply a matter of purchasing and attaching some sort of cord
between the units, and if so, where do I get this? I am not sure if they
are fairly universal or do I need to contact one of the vendors for this,
and if so, which one...Furuno or Garmin?

Is there more to it than this? Any idea how much it costs?

Thanks!

Gary

€

 

[Geoffrey W. Schultz]

I recently bought a 1995 320 Albemarle Express Fisherman. It has a
Furuno 1830 Radar and a Garmin 220 GPS. In reading through the
manuals for these pieces of equipment, I have noticed that it's
possible to connect a GPS to the radar and it will display some nav
information on the Radar unit as well as having the ability to plot
the speed and direction of various targets on the radar.

Is this simply a matter of purchasing and attaching some sort of cord
between the units, and if so, where do I get this? I am not sure if
they are fairly universal or do I need to contact one of the vendors
for this, and if so, which one...Furuno or Garmin?

Is there more to it than this? Any idea how much it costs?

Thanks!

Gary

You can find the owner's manual on the Furuno web site. Your specific
manual is at

http://www.furuno.com/Furuno/Doc/0/U6PJCJDB940K703F8KU2HHIG03/1830
+Operator%27s+Manual.pdf

If it's like my Furuno you'll simply need to get a Garmin cable and connect
the NMEA output from it to the radar.

-- Geoff

 

[William G. Andersen]

I needed two cables to connect my Garmin GPS to my Furuno 1622 Radar.
The Garmin cable costs about $35. It has a Garmin connector on one end and a
serial connector (for a PC) on the other.
My Furuno cable cost about $60. It has a Furuno cable on one end and bare
wires on the other.
I wired a serial connector to the Furuno bare wires and plug one serial
connector into the other.
Your Furuno may just have screw posts for the Garmin wires to connect to.
When the GPS is wired to the radar, the radar disply can indicate your
course and speed, latitude and longitude, and waypoint bearing and distance.

 

[Bruce in Alaska]

=========================================

Is that sufficient to support the so called "ARP" plotting functions,
or do you also need a flux gate compass to provide heading
information?

No, ARPA functions are much more complicated that the simple NEMA
interface on the small commercial Furuno Radars. You need an compass
input to get the Waypoint Popsicle on the Radar Display. ARPA takes a
complete ARPA Unit which is a complete cpu based system that is in
addition to the basic radar display system.

Bruce in alaska

 

[Gary]

I saw a few people said something about needing a fluxgate compass. I also
have a Robertson AP3000X autopilot that is connected to a fluxgate compass.
Am I going to need 3 cables now, or is the GPS most likely connected to the
fluxgate compass already?

 

[Andy K.]

======================================

I'm under the impression that ARPA is included on the Furuno 1833 that
I've been considering. Is that not correct? I would like to be able
to eliminate the flux gate compass requirement by assuming COG =
heading but not sure if it's possible.

The ARP11 (10 target ARPA) is listed as an option for your radar. As far as
the data connection between the GPS and radar, if the Garmin cable is the
same as most of the others they make it would have some un-terminated wires
plus the red and black for power. You need the NEMA data cable for the radar
(the one with the bare ends). Nothing more then connecting 2 wires from each
cable and setting up the data outputs and inputs on each unit. Sorry I can't
remember the colors you need to connect and the info is at work.

Andy K.

 

[Bruce in Alaska]

The ARP11 (10 target ARPA) is listed as an option for your radar. As far as
the data connection between the GPS and radar, if the Garmin cable is the
same as most of the others they make it would have some un-terminated wires
plus the red and black for power. You need the NEMA data cable for the radar
(the one with the bare ends). Nothing more then connecting 2 wires from each
cable and setting up the data outputs and inputs on each unit. Sorry I can't
remember the colors you need to connect and the info is at work.

Andy K.

I am under the impression that ARP is and add on option for all the
small commercial Furuo Radars. I am not 100% sure on that exact model
(1833) but I bet Doug could give us a difinitive answer. Any add on
option is going to cost BIG BUCKS, however and probubly not worth the
cash for a noncommercial users. The standard NEMA input for these type
Furuno Radars is to display the Position Information, Speed, Course over
Ground, and Next Waypoint Bearing and Distance, at the bottom of the
screen in the NAV Info Position. If you want the Waypoint Popsicle to
display on the screen, then you must input Compass Data on the Gyro
Input, and that is a seperate connection from the NEMA Input. All the
Furuno's I have dealt with will NOT accept Compass Data from the NEMA
Data Stream, but only on the Gyro Input.


Bruce in alaska

 

[William G. Andersen]

Using NMEA from my Garmin (Etrex Mariner or GPS 12) to my Furuno 1622 does
provide the Wapoint Popsicle, in addition to everything else.

 

[Bruce in Alaska]

Before I type and display my ignorance here about the ARPA issue, are we
talking about an 1830 or 1833? I see both mentioned in the trail.
IF I had an 1830 radar, I would want to make sure it has a version 08 or
higher EPROM and the revised modulator board in the scanner. Otherwise you a
prime candidate for blown modulator FETs. To determine the EPROM version,
turn on the radar and during the initial Time Delay before the radar can be
switched to transmit, the Resident Version of the EPROM is displayed on the
CRT. The last two digits on the right indicate the EPROM version. Version
08, 09, etc means an OK system. Version 07 and below, get the modification
done requiring a new EPROM in the display and new modulator board in the
scanner. Back in 1990 Furuno covered this as a warranty item. No idea if it
is still covered.
Compass input to the Furuno is via the gyro inputs and may be from their
AD100 conversion box or a flux gate compass, such as Furuno, KVH, etc. There
was a wiring change in mid production of the gyro connector, so make sure
you have your manual handy to match what you have.
As I see it, for an 1830, NMEA will give you lat/long, speed and
range/bearing to a waypoint.. It is not used for compass. Pin 3 of the
Furuno NMEA cable is receive data +, and pin 4 is receive data -.
Doug K7ABX

Yep, that's how I remeber it as well Doug. I haven't seen an 1833 in
person, but my assumption (I know...Bad idea) is that the 1833 would be
the same. Maybe Furuno has changed the firmware in the 1833 to use
NEMA compass data, for generating the Waypoint Popsicle, but it hasn't
been the case in any of the previous models.

Bruce in alaska

 

[Gordon Wedman]

In " The Radar Book - Effective Navigation and Collision Avoidance " by
Kevin Monahan, he points out that the compass bearing given by a GPS will be
unstable at low speeds. If you want your radar to show proper compass
bearings and work in the North-up/Course-up modes he says you must connect
to some type of fluxgate or gyro compass. So if you just connect your GPS
NMEA output to your radar it seems you may not get correct heading
information while creeping along at low speed, for example, in fog.

 

[Rodney Myrvaagnes]

In " The Radar Book - Effective Navigation and Collision Avoidance " by
Kevin Monahan, he points out that the compass bearing given by a GPS will be
unstable at low speeds. If you want your radar to show proper compass
bearings and work in the North-up/Course-up modes he says you must connect
to some type of fluxgate or gyro compass. So if you just connect your GPS
NMEA output to your radar it seems you may not get correct heading
information while creeping along at low speed, for example, in fog.

Monahan's book may predate the discontinuance of selective
availability. You have to be going very slowly indeed to make the GPS
track reading less stable than a mag compass nowadays.

It is easy enough to compare on your own boat.





Rodney Myrvaagnes NYC J36 Gjo/a

"Religious wisdom is to wisdom as military music is to music."

 

[Bruce in Alaska]

In " The Radar Book - Effective Navigation and Collision Avoidance " by
Kevin Monahan, he points out that the compass bearing given by a GPS will be
unstable at low speeds. If you want your radar to show proper compass
bearings and work in the North-up/Course-up modes he says you must connect
to some type of fluxgate or gyro compass. So if you just connect your GPS
NMEA output to your radar it seems you may not get correct heading
information while creeping along at low speed, for example, in fog.

That would very much depend on the GPS, its Position Update Rate, and
internal Math Capabilities. I would suspect that any GPS that updates
faster than every .5 Sec, and has a good floating point processor, would
give good resolution down to at least 2 to 3 knots.

Bruce in alaska

 

[Rodney Myrvaagnes]

Not to mention the huge difference between COG and heading, when on a slow
speed and a tidal current....

The latter is a relevant concern. I haven't seen a recent GPS that had
a problem at walking speed or even slower, but they do say where you
are actually going, not your heading.

The difference can be considerable in areas with strong currents.




Rodney Myrvaagnes NYC J36 Gjo/a

"Religious wisdom is to wisdom as military music is to music."

 

[Tamaroak]

I have a Raymarine SL72 Plus radar and a Garmin 182 GPS/chartplotter. I
was at the dock in Bayfield, Wisconsin this summer and a guy came by and
wanted to see my electronic setup. He told me I could interface the two
and promptly crawled under the dash and connected a wire from each
together and that's all it took. He had to change the default setting on
the Garmin, but it works like a charm.

No cables, no nothing. It cost me a beer.

Now when I put the radar cursor on an object it gives me the GPS
coordinates and more.

Capt. Jeff

 

[Dave Baker]

The latter is a relevant concern. I haven't seen a recent GPS that had
a problem at walking speed or even slower, but they do say where you
are actually going, not your heading.

The difference can be considerable in areas with strong currents.

Especially if your engine is in reverse!

Dave

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All replies to the group please.

 

[Gordon Wedman]

would
give good resolution down to at least 2 to 3 knots.<

Exactly Kevin Monahan's point. At low speed, creeping through fog, you will
not get a stable heading readout. I have a Garmin 182C plotter with WAAS.
Below 2 knots I start to see the "compass" heading wandering.
Kevin's book is quite recent and takes into account the current situation.
I'm planning on purchasing the Raymarine Seatalk/NMEA conversion box so that
I can feed my Autohelm fluxgate compass heading to my JRC radar. The JRC
has two NMEA inputs, one for GPS and one for Compass. Internal software
selects the Compass heading input over any GPS heading input.
Maybe this isn't necessary a lot of the time but I'd like to be able to rely
on what the radar is showing at all times.

 

[Bruce in Alaska]

============================================

I just got back from the Ft Lauderdale boat show and had a chance to
talk with the Furuno factory reps. It turns out that ARP functions on
the 1833 are possible but require an optional circuit board that costs
about $600 or so. No where is the circuit board mentioned in the list
of 1833 options on the Furuno web site and several dealers I've talked
to were not aware ot it either. There is also an additional circuit
board available that accepts composite video input and allows it to be
displayed either full screen or in a window.

Yep, that squares with my memory. ARP is a seperate function that must
be added on to any of the small commercial Furuno Radars. Once you get
into the Big Boat Stuff it is built in, but the cost are significant.


Bruce in alaska

 

[Andy K.]

============================================

I just got back from the Ft Lauderdale boat show and had a chance to
talk with the Furuno factory reps. It turns out that ARP functions on
the 1833 are possible but require an optional circuit board that costs
about $600 or so. No where is the circuit board mentioned in the list
of 1833 options on the Furuno web site and several dealers I've talked
to were not aware ot it either. There is also an additional circuit
board available that accepts composite video input and allows it to be
displayed either full screen or in a window.

All 4 of the 1833 radars on the Furuno site list the ARP11 as an option.
Look under "Features/Specs".

 

[Dave Baker]

When will GPS compasses come down in price? Just came from the bridge of an APL
container ship where they had two Sperry GPS compasses. They have replaced mech
gyros on many ships and are very accurate and responsive. Cost about $17,000.00
each.

17000???

How about the CSI-Wireless Vector Lite? We've been using one for over a year
now on oil rigs.

US$3k.

Dave

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[Andy K.]

Furuno makes GPS compasses is the $ 5-8K range. A GPS compass is an
entirely
different critter from the NMEA compass information provided from a GPS
sensor. A GPS compass is not using the datastream. It is using three
antennas at least and doing carrier signal phase difference measurements.
A
proper installation requires a technician who understand radio wave
reflections, and even he may have to reposition the antenna array a few
times for proper results. It is really trial and error at first. I know of
two identical 80 foot Alaska crab fleet boats, where one system works
super
and the other is still fighting problems. And, yes, they provide Furuno
AD-10 format compass data to a radar. A diagnostic program may take 12
hours
to run for results.

Doug K7ABX

KVH has one for around $3k. Have not seen it in use.