Navico Broadband Radar, a really big deal?
One reason I wish I were at METS today is that Navico not only debuted its Broadband Radar, but may be running it in their booth. That’s possible because this 18” solid state radar transmits at “1/2000th the power of typical pulse radars.” And it might even generate meaningful images inside that huge show hall as the technology is supposed to be amazingly good at resolving short-range targets (as suggested above). The various Lowrance, Northstar, and Simrad MFDs that are going to be updated to support this scanner will even have a 1/32 nm range. So…high target resolution, very low power draw, almost no dangerous radiation, and no tuning or warm up time needed…is this an interesting development, or what?
I first heard of solid state marine radar a while back (SharpEye) and got more excited when I learned (off the record) that Navico was working on this recreational version. The claims on their new Broadband Radar site may be true: ideal compliment to large yacht radars (and AIS), or ideal primary radar on smaller boats (sailboats particularly). But of course we won’t really know until we get to see these scanners in action. I’m told that they’ll ship during the second quarter of 2009, and at a price somewhere between conventional 2 kW and 4 kW sensors.
Incidently, some worthy products won DAME Design Awards at METS today, and some didn’t (my thoughts tomorrow). I’m also hoping to get some guest entries from Amsterdam, maybe even some more Jeff Hummel observations. But meanwhile I’ve been busy (and content) putzing around the lab; I think you’ll get a kick out of how some very dissimilar product testing came together today.
A real question about Navico’s Broadband Radar is its effective range. The new site doesn’t say much about that, but a press release I just got states:
“Boaters using these new generation radar systems will be able to clearly differentiate between docks, channel markers, pilings, moored vessels and other important targets at ranges down to 1/32 nm. Navigators can also expect 2- to 3-meter target resolution to 10 miles with a maximum range of 24 nautical miles.”
Ben / Others.
Off to mets tomorrow (few delays in getting there as always) will get as much info on this as possible so Ben can post it.
Looks very interesting
WOW …. WOW again.
And the broadband name seems well justified on the web site.
No mention of Raymarine or Garmin ?
Finally, a cure for the obsolete magnetron!
So here’s the question: How can a low power solid-state transmitter offer range equivalent to a 2kw+ magnetron transmitter? Answers: by not wasting energy AND by having a very stable frequency that allows the receiver selectivity to be tightened.
If you’ve never looked at the output spectrum of a magnetron, you may not appreciate that the 2kw (or 4kw) output of a maggie is splattered over a quite wide frequency spectrum. In addition to that, within a single maggie transmitter pulse, the frequency shifts somewhat. To date, the best way for receivers to accommodate this blunderbuss-like output pulse was by opening up receiver selectivity in an attempt to capture as much of the reflected energy from the target as possible, and that just opened the receiver to noise as well.
The output of a solid-state transmitter (probably from an impatt diode array???) is stable and narrow. Transmitter peak pulse power may be, I’m guessing, only 25 watts or so (contrasted with the 2,000 watts of the maggie), but it is energy that spans a very narrow spectrum, and is also very stable. As a result, the receiver selectivity can be narrowed to the minimum, letting in only the frequencies containing intelligence, and excluding the noise. Sort of like opening the barn door only enough to let in a specific horse, rather than the entire thundering herd, including horses, cattle, sheep, dogs, etc.
An important marine benefit of solid state is that when dealing with a very sharp, low power pulse, the transmit/receiver “switch” can be very fast. Just as in humans, a receiver cannot listen while it is transmitting. Plus, there is additional delay time between the cessation of a magnetron output pulse, while the rf section “switches” to receive mode, that adds to the null area near own ship location. This delay is effectively eliminated with solid state, enhancing the radar picture at minimum range.
Manufacturing solid-state radar should entail a much-reduced parts count and the total elimination of a high power modulator section, thus improving reliability.
There are negatives, though. No longer will you be able to hold a wiener on a stick in front of the antenna to get a hot meal in the cockpit.
It’s is long past time that the maggie was consigned to the dust bin of maritime history and left to the microwave oven industry.
Ahhh, now I see. My previous posting was prior to my having looked at Navico’s broadband radar website. But having been there, I now have a more apt analogy.
Comparing the Navico cw (continuous wave output)radar to an aviation solid state (pulsed output) radar, as I was doing, is only partly valid. The narrow frequency spectrum and frequency stability benefits of solid state vs the maggie still stand as valid observations. But a more appropriate aviation analogy is comparing Navico’s new radar to an aviation radar altimeter. An aircraft “rad alt” transmits a continuous (ie cw) signal that is, let’s say, “coded”, so that an echo reflected from a target can be discriminated within the receiver in a very accurate manner. The system still operates by measuring the round trip time between a reference “mark” of some type enbedded in the transmitted cw signal, and the return of a target echo.
Importantly, the macho orthodoxy that “the more transmitter power the better” is no longer valid. A low power solid state radar will trump a maggie radar six ways to Sunday. What does matter is overall “Loop Gain”, which is the total effectiveness of the round trip loop, that includes: transmitter output + antenna gain + radome transmissivity + atmospheric attenuation + target reflectivity + atmospheric attenuation + radome transmissivity + antenna gain + receiver selectivity and gain…and only then is sent to a display. It has long been believed that high output power was the be all and end all. Now the maggie is on the way out.
Kudos to Navico for this creative approach.
WOW … I had to say that again …
Very impressive, looks just as clear as the radar I observed on a cruise ship last holiday.
However, this seems different then the Sharp Eye, but maybe its the same and described differently?
The increasing frequency approach, to determine distance to the object … very easy to understand. They make no mention of detecting doppler shift to obtain the speed the target is moving at like I roughly recall reading about with SharpEye ?
With solid state could they design a radar that could detect which way it is tilted, and then, with no additional moving parts, steer the beam so it is aligned with horizon. That way a heeled sailboat could get full benefit from the radar without the need for a heavy leveling accessory on the mast ?
FM/CW radar has been around for a long long time, but the ability to generate a high quality Linear Frequency Modulated waveforms has been perfected by the development of Direct Digital Synthesizers. Without that synthesizer capability the modulation distortion can be severe and ruin the potential range resolution. Larry Brandt has it right in comparing the NAvico radar to a Radar Altimeter – that is precisely the same modulation.
The radar transmits constantly – never ending with no pulses. The receiver is also open for reception at all times. The problem is self jamming – which the Navico folks have conveniently solved with dual antennas – one transmit and one receive – so that the jamming is kept to a minimum. The minimum range of such a system is the range resolution of the radar – so if they transmit a 60 MHz linear frequency modulated waveform (it looks like a sawtooth up and down pattern) then the theoretical range resolution and the minimum range is 8.2feet.
And yes Virginia if you can see to 8.2 feet and you use cellphone power for transmit you can turn it on inside the conference center and demo it live.
The SharpEye Radar is a close cousin to the Navico system – but it uses Non-linear FM WITHIN a pulse to create what is known as a Pulse Compression Radar. These systems transmit long pulses (like 0.5 milliseconds) but have range resolution of a few feet – like 15 – 35 feet at 5 Nmi. Tranmit power is about 100+ watts
Power is not all. Receiver Bandwidth is the other side of the equation. The received signal has to compete with the noise power within what is called a matched filter bandwidth. A 1 uSec pulse requires a 1 MHz wide receiver bandwidth (or more) and a 70 nSec pulse for short range resolution needs 14+MHz to resolve 35ft resolution.
Now compare an FMCW radar that has a 1 milisecond long linear FM waveform period. The receiver bandwdith is 1 KHz – 1000 times less bandwidth than the 1 MHz needed for 1 uSec pulse with 500ft range resolution. THat means you need 1000 times the power to overcome the noise power in a pulse system receiver. Now if that 1 KHz FMCW system has a 60 MHz Linear FM “chirp” then it can use 1000 times less power to resolve 8.2ft range gates – ALL THE WAY to max range. HOwever, if you choose to use that resolution to 24 Nmi – that means you need nearly 18000 pixels to display the data. No doubt Navico adjusts the transmitted bandwidth as a function of range to use a more modest display. But close in they can use very high range resolution.
I salute the folks at Navico for being clever and finally bringing this technology to market. They probably use about 1 watt or less. An altimeter with 3ft range resolution only needs 0.1Watt to see 8000ft of altitude with a low gain antenna.
While SharpEye may seem cool and new, Honeywell has been shipping a Pulse Compression Weather Radar for aviation since 2005 (see http://www.newfromhoneywell.com/why_intuvue.php) and has just demonstrated a MARINE version of that system with 40 watts of power in September. The system is not for sale – but is being considered for partnerships with existing radar companies.
The days of the Magnetron radar have been doomed for a long time – since the Direct Digital Synthesizer and Phase Lock Loop Technologies were unleashed around 1996-7. You will see many more transformations in the next few years. It is perfectly silly to use Magnetrons for Recreational radar systems – and commercial systems should need no more than a Solid State Pulse compression system. There is no reason that the FM/CW system could not be adapted to an open array – though that would require a bulkier array if two antennas are used.
FM/CW signal processing requirements are modest and present day systems can use off the shelf DSP chips for $10 or less.
What clever company will now understand how to use a SINGLE antenna for FM/CW radar like we did back in 1995 for missile seekers at millimeterwave frequencies (35 -95 GHz).
Larry – most Radar altimeters use TWO antennas – but watch for a new one coming – I have patented a SINGLE antenna radar altimeter. Clearly that applies to Marine Radars as well. PS I Have patents on this technology.
It may be too early for this question but – Does anyone know if this new radar technology can be used with the Furuno NN3D system? Just deciding if I should delay the planned purchase of a NN3D system including radar..
Mike, Furuno may have something like this up its sleeve (I will definitely ask) but I’m pretty sure that this Navico Broadband radar–though it’s Ethernet–is only going to work with certain Lowrance, Northstar, and Simrad machines (the list is at http://www.broadbandradar.com).
That said, Furuno’s current UHD radar is very, very good, and it’s actually shipping 😉
Now that the next generation RF approach is clear, my purchase is only delayed until I know which radar manufacturer will happily support use by laptop/notebook based software, such as Coastal Explorer. I’d even be willing to pay a small license fee.
I have the current Furuno unit and have received images very similar to the screenshot about.. I can pick out 2 kayaks in a marina full of boats and other targets.
That said, I’m sure it is using much more energy.
If Furuno comes out with an RF Antenna, then I’d give it serious consideration. I would imagine that it would work with the Furuno network just like the current ones do so I wouldn’t need to purchase another MFD.
For me… Lowrance just isn’t an option. I’ve had bad luck with their products quality too many times in the past. Pretty much a Furuno guy now. 🙂
I went to METS yesterday, and not a lot more detail could be obtained. Big displays showed the same video as on Youtube. They had a turning scanner with the radome off, but it wasn’t connected up to a display and the spokesperson I talked to couldn’t say if it was actually turned on. The radome looks “typical” with a much wider diameter at the bottom than at the top. I guess this is so you can show off that you’ve got the new broadband radar to ya’ mates… The box was shown at several other stands like Scanstrut etc. to show off how it looks. Maybe I was unlucky in who I talked to. It seemed ready for market introduction, but this person also could not tell me when it would start selling.
I did learn that the radar emits less than 1/10th of the power of a cell phone, and uses 17W @ 13.8V in operation and 1.6W @13.8V in standby. This information is also online .
I’m a old school guy who teaches engineering.
I realize that marine radar transmitters utilizing magnetrons have been around a while but, I doubt that their days are limited. Their pulsed operation makes them quite efficient and their peak power output makes them excellent at long range detection. Especially with weak targets. The notion that they are not reliable or dependable is hogwash.
While marine X and S band radar transmitters take up a considerable portion of the electomagnetic spectrum, the spectrum is allocated, known to all, and will remain that way for at least the next 25 years, if not much longer.
I’m sure that solid state systems will become more popular in the future but, I’ve yet to see or hear about one that can perform as well in all conditions as a magnetron transmitter. This is especially true where high power is critical. They exist in the military and in a lab but, they will certainly cost much more much more than a magnetron based marine radar transmitter. Consider certain real atmospheric conditions that mariners face on our planet. Rain and Fog greatly attenuates(reduces performance)of low power solid state radar systems. The followers of this site will all see what Ben has to say about it when he gets his hands on one.
Pound for pound, dollar for dollar, and watt for watt, Magnetron based marine radar transmitters will probably offer the best all around performance for a long time to come. If they didn’t we would have seen them in the commercial world before Navico, especially with X-band systems. For example, even though Kelvin Hughes has introduced Sharp Eye, it is only an S Band System.
Incidentally, I heard a rumor that only a few years ago, Garmin tried to develop a solid state X band marine radar that equalled the performance of a magnetron based system. They eventually gave up and developed magnetron based transmitters. Ben, maybe you can get them to comment as well.
Note to all who’ve been following this thread: Kees’ interesting and long post above just got added because it accidentally went into the junk comment folder.
I swear that posting comments is going to get better, but in the meantime please use minimal html and keep links to one or two per comment.
As an old school guy myself, I didn’t intend to imply that current maggie radars were not adequately reliable or dependable. Certainly, I am very pleased with my Raymarine 2kw system.
The point I intended to make about solid state radar was that they should be easier to manufacture because they no longer will have an HV modulator section, and because the overall parts count will be less. These are both factors that also point to even higher reliability than at present.
Personally, I am not convinced that high rf (maggie) output power = better performance with weak or long range targets. My perspective, though, is admittedly an aviation one, in which field for the last 10+ years the standard has been solid state. The ability of a 250 kt airplane’s radar to paint and penetrate a thunderstorm sufficiently for a pilot to make critical safety judgements is a very strong testimonial in favor of solid state. I have often seen superb weather echos displayed well beyond 100 nm range. Every time you step into any modern Boeing or Airbus airliner you’re trusting your life to a solid state radar that has a maximum *peak* power of barely 100 watts, and on most regional jets and turboprops (such as the Bombardier CRJ) a maximum *peak* power of only 25 watts, whereas the generation previous depended on 5kw+ maggies. These modern low power radar systems perform at long range at least equivalent to their maggie forbears. (See my discussion of Loop Gain, above.)
An additional benefit to aviators of solid state radar was being able to quantify water droplet motion and display it as turbulence. I don’t see this as being of importance to the average boater, with perhaps one exotic exception: the potential benefit to racing sailors using doppler assessments of rain clouds to find favorable winds.
X- and S-band maggie radar will be with us for quite some time, but the bell has begun to toll.
Larry / Jeff-
First – Kelvin Hughes has already gotten an X band system qualified through Qinteq and is for sale.
Larry is right. Aviation Weather radars from Collins and Honeywell are all solidstate and have been for 20 years. The RDR 4000 PCSS radar has demonstrated storm detection at 320 Nmi on the C-17 aircraft with 40W Peak Xmit.
Lastly – AVERAGE POWER is KEY. Consider the DUTY CYCLE – Maggies have duty cycles of 0.1% or less while Solid State can be 10 – 20%. So the average power of a Maggie at 4KW is 4W and solidstate radars at 40 – 100W are 4 – 10Watts AVERAGE. Even this 0.1W AVERAGE power system is not far behind!! Now consider the receiver bandwidth for LONG pulses used on solidstate systems are several times narrower than the maggie. That means the SS systems have an ADVANTAGE over Maggies. I used to work on a 60Kw Weather radar with dangerous X ray radiation from the power supply and it was so dangerous that it must not be on near FUEL TRUCKS – or it could cause explosions, to say nothing of cooking the eyes of employees! Modern SS radars easily outperform that radar and it is no longer in production.
Maggies have had only a COST advantage for a long time – but this CW system has put an end to that. The small Radome type of radar can easily be replaced with an FM/CW radar that is far safer and just as effective in rain etc. The losses are the same for both maggie and ss and the sensitvity advantage goes to SS with very low receiver bandwidths.
Larry is also right about DOPPLER capability or coherent transmit and receive. No such luck on a maggie without a STALO etc etc. In fact – if the NAVICO folks made some provisions – the FM/CW system would be AWESOME for motion / Doppler detection (within the ambiguity limits). I respectfully suggest that you make some calcs for a solid state radar that can use pulses as long as 500uSec – but with resolution of say 150ft and see what kind of detection range you can get with 10% duty cycle and say 100W transmit and 30dB of antenna gain. You’ll see what we mean. Don’t forget that really high power Maggies need stuff like radio isotope plasma receiver protectors followed by several PIN diodes. That is all lossy, raising the noise figure – the spectral splatter is wasteful and ITU is now chasing Maggie makers to contol spectrum splatter – leading to costly and complex modulators.
Lastly – maggies degrade in performance over time – but SS is rock solid for YEARS – same performance year over year. Commercial operators replace maggies every 12 – 18 months.
Cost has been the only advantage till now……
I can’t resist this example – assuming R^4 point source characteristic – to DOUBLE the range of the 4Kw maggie radar you need 64Kw for the same antenna size / pulse lenghts! Even R^3 for area reflections would be 32Kw! So Power is the HARD way to go.
All this talk about 1 two thousandth of the power of a regular radar, followed by almost in the same breath, huge power savings for small boats. There is a certain amount of “the numbers game going on here”.
A 2kW radar does not actually transmit 2000 watts in the same way that a 1 watt CW radar actually does transmit 1 watt. It actually transmits a brief pulse at the 2 kW amplitude and then rests for a long time. The ratio of on to off depends on pulse length and repetition frequency.
If you do the math at long ranges a typical 2kw radar actually averages about 2 watts. At short range it is around 0.5 watts.
This is reflected in the actual DC power consumption figures, 17 watts at 13.5 volts for the new solid state radar but still only 28 watts for a typical 2kw magnetron radar. So the power consumption advantage is not as great as some figures might lead you to expect.
Also it is generally accepted that tissue damage is related to heating effect (defined by average power), so again a magnetron radar is not as dangerous as it might seem when comparing 2000 watts against 1 watt. This is different to a microwave oven where 800 watts from the magnetron is 800 watts continuous.
The other thing we have to remember is that we see big improvements in range resolution especially at close range, but, the angular resolution is still defined by the beamwidth of the antenna. This means that depending on whether 2 targets lay close together on a radial or close together on a circle we will see either a big improvement in target separation or very little improvement.
Having said all that I think solid state is in our near future. Combined with advanced signal processing the next few years should see some great new products.
shame all these radars out there cannot talk to each other. imagine if you could get a visual of an area that is a combination of all the radars in the area.
the network idea for all your electronics on the boat is great, and way past due, but the real significance of the marine network will be when all your electronics talk to everybody else’s electronics.
As the old saying goes, “there’s nothing new under the sun”. As fresh as solid state radar is in the marine field, I would like to document the following historical points.
Back in the early ’60s, I was a crew chief (USAF E4, which was three stripes back before rank inflation) on an FPS-24 search radar located on top of a mountain in Idaho. Output peak power was 10 MEGAwatts in the UHF band, with a pulse some 20 usec long. It was a solid state radar – no maggie – and it used pulse compression to achieve excellent range resolution in spite of a 2-mile-long pulse width.
Assuming this is equivalent to a 2 kW magnetron radar with an 18″ radome and 24 mile range, the specs for a magnetron Simrad show it uses 25 W and Simrad’s specs for its new broadband radar show it uses 17 W with an output power of 0.1 W, so it does use a little less power. Probably lots of the power in both versions goes to the radome motor. Simrad’s 4 kW 24″ radar uses only 5 more Watts than its 2 kW 18″ radar.
Not all manufacturers list the power used. Garmin says its 4 kW radars use 33.5 W; there is an 18″ 2.2 kW Furuno which uses 38 W.
According to the internet, magnetrons are about 50% efficient, more or less. Part of the input power becomes RF and part becomes heat.
A magnetron is a vacuum tube, so has a hefty current suck for filaments.
But the antenna drive motor has to be one of the larger power demands, and will remain a factor for either solid state or maggie radars. Still, 17 watts versus 25 watts…that’s a 50% reduction, saving 3/4 amphour. Important for sailing vessels.
Presumably the comparison stats do not include the display loads, backlighting being another current hog.
The Garmin website says the GMR18, GMR18HD, GMR24, GMR24HD all use 33.5 Watts. The Northstar website says their 2 kW 18″ 24 nm radome and their 4 kW 24″ 36 nm radome both use 25 Watts. Since these are all just the radomes, there would be more power required to run the display.
The Furuno unit I quoted above was the 1715 with a 7″ mono LCD display. That uses 38 W max, and 8 W in standby mode. That does include a display, so that’s not really a fair comparison.
I finally found the Furuno NavNet 3D power numbers. The MFD8 display is 29 W, and 73 W with the DRS2D radome or 77 W with the DRS4D radome. The MFD12 display is 41 W, and 86 W with the DRS2D or 91 W with the DRS4D radome. The DRS2D is 19″ 2.2 kW 24 nm. The DRS4D is 24″ 4 kW 36 nm. Subtracting those numbers, the DRS2D is about 45 W and the DRS4D is about 50 W.
It’s possible that the computing power necessary to do high definition radar is nearly as much as the RF power.
Also worth considering the Furuno’s use a high speed stepping motor for 48 RPM operation so that will cause a jump in power consumption.
May be able to get some real readings in current draw when i do some service work later on in the week.
The Navico radar spec states 100mW transmit power with a 5deg horizontal beam width. I did some work on FM/CW radar a few years ago, and still have a spreadsheet for the radar range equation. Assuming an effective receiver bandwidth of 3kHz (this is set by the length of the FFT performed on the received signal,also by the residual phase noise of the transmitted signal) I get a maximum range of 1 to 2 nm with a 10sqm target.
Remember that a sailor doesn’t need the radar on all the time! If it has zero warmup time, it can be OFF for two minutes, do a quick scan and go back to off, instead of sitting at standby drawing 8W (Furuno 1715, best in class so far…)
Does “broadband” also equal the ability to output the signal to a computer monitor? I am visualizing all nav/boat data delivered to my tablet PC… when I hear broadband, I wish/hope/pray that I can plug it into my network in some way. Looked into the Nobeltec, but too expensive. Also wouldn’t mind getting away from dedicated displays. Does anyone know if this data can be output to a computer?
The term broadband (perhaps used incorrectly) is being used to position the technology as more modern then it’s recreational predecessors … but could be loosly justified based on a feature of the unit to transmit/receive radar energy across multiple frequencies to increase the information gathered from a target vs. a single frequency … nothing to do with plugging into a network.
Robert, Navico’s Broadband Radar scanners — like most modern recreational radars — do their own signal processing and deliver the results via Ethernet. So they COULD be used with computer charting programs if Navico developed an SDK and licensing program. I, too, wish that Navico would consider that strategy, but don’t think they’re interested at the moment.
More on this radar:
“Broadband” is a slippery term:
This is probably a goofy question, but I’ll ask it anyway because I have not been able to find a good answer anywhere..
I’ve heard a that broadband radar is excellent for close up targets, but not so good for targets farther away. What I don’t understand is why I would need detailed info about a target that is 16 miles away.. I owner a trawler.. At full speed, I travel at 8 knots.. Why do I need to look 2 hours into the future? Even if the other target is closing fast in my direction, I will still have plenty of time to recognize it, and do something about it.
What am I missing?
Andreas: The discussions assuming that there is a significant loss of effectiveness at longer ranges probably found their basis in an off hand comment that this radar may be less spectacular further out.
That started the snowball rolling, and it’s not been supported by factual observation since then. I’m willing to bet this issue is overblown.
All you are really missing is the opportunity to grouse about something truly new to the recreational marine market, that pushes whatever we now have out of the limelight. Its a human thing to resent someone calling our shiny new toys obsolete!
So which is better for a medium size cruising sailboat Furno HD Radar or Simrad Broadband Radar?
I doubt there will be a simple answer to that question. I’ve been testing a BR24, and will soon be comparing it side-to-side with a new Raymarine Digital 18″ radome and a Garmin 18HD. I’d like to try a Furuno 18″ UHD, too, but haven’t made arrangements yet.
The impression I’m getting so far is that Broadband lives up to its near-range performance claims — in fact, it’s pretty amazing in tight quarters — but I’m not at all sure that it matches other small domes in terms of mid and long ranges.
Plus there are lots of other radar factors, like MARPA, dual ranges, fast speed scanning. And there are the MFDs the radars are attached to; you don’t just buy a radar anymore.
Larry is wrong about the AN/FPS-24 being a solid state radar, although he is correct that it did not use a magnetron. Its intermediate power amplifier was a twystron and the final amplifier was a large RCA vacuum tube triode (with 96 sets of elements inside a single glass envelope). This triode was also used in powerful commercial radio stations and operated in the VHF band. It was capable of working at 30-40KW average power and in the AN/FPS-24 radiated 18µsec pulses at a 333/sec rate (duty cycle of .006); these were frequency coded and later compressed down to 1-2µsec in the receiver.
I was a Radar Maintenance Officer at Mt. Hebo Air Force Station, Oregon 1960-1962 and had been trained on the operation of that radar.