Simrad HALO24 Revolutionizes Dome Radars

9 Responses

  1. Ben Ellison Ben Ellison says:

    I’m keen to see more details (that should be online soon) and hopefully Ben Stein will see Halo24 in action at IBEX, but this already sounds like a premium solid state Doppler radome. There are already similar press releases out for B&G and Lowrance HALO24 radars. In fact, Navico announced a boatload of new products today, so more to come.

  2. Larry Brandt says:

    How is it possible to move the radar marketeers away from this crap: “long-range detection capability, up to 48 nautical miles”??? This brochure buzz is intentionally designed to deceive, leading an inexperienced potential purchaser to think they will see ships out at 40+ mmi. They ALL do this. I call BS on them. Apparently the radar manufacturers’ marketing departments are under the impression that the earth is flat.

    • Ben Ellison Ben Ellison says:

      Agree that claimed ranges are dicey, but then some valuable targets are taller than ships. For instance, the Simrad 4G radar I had mounted about 10 feet off the water has imaged Cape Anne, MA — rocky, yes, but not very high — 32nm across the Gulf of Maine… back when most folks thought that a “weak” solid state radar couldn’t do that. And how about intense rain cells?

  3. Ben Ellison Ben Ellison says:

    More detail about the Halo24 is rapidly filling in at Navico websites, and I’m really happy to see that it has true dual range capability, dual overlay too, like the 4G, but simpler install wiring (just power & Ethernet):

  4. abbor says:

    The long range detection capability is important for detecting weather cells. distant land we can see at the charts. I’ve seen Halo24 screen shots showing weather cells at 41 NM, but I don’t have access to it right now.

    But Halo24 is actually giving solid returns for land 48 NM away. Here are some screen shots from Auckland NZ, the target at 48NM is Great Barrier Island. The areas we see at the radar is 400-500m above sea level.×1080/screenshot_2018_10_15_15_05_12_38d10002e3cafb42515eac3e4d3dc3a82920fdbd.png×1080/screenshot_2018_10_15_15_05_16_34422315cddbcb23c65416bb9719c5fe4aa96dba.png×1080/screenshot_2018_10_15_14_59_33_15b6bada5bdc7cdedd2627c44302523e226bac29.png

    I’ve used Halo24 for a while now and I’m really impressed by the performance. As good as 4G at shorter ranges, and much better at longer ranges. The Doppler processing is doing an excellent job in coloring approaching and diverging targets.

  5. Larry Brandt says:

    Picking up a, let’s say, 500 meter high target at 41 nmi??? Sure, it ought to be able to do that. Converting 500 meters = 1640 feet (because the only formula I know is in feet, not meters). The formula is 1.33 x sqrt of height of radar PLUS 1.33 x sqrt height of target. That certainly works for picking up the peak of Great Barrier Island. Slam dunk. I have duplicated that with my Raymarine 4k on the Columbia River, picking up Mt Hood strongly at 48 nmi. My gripe has to do with marketing the thing. The brochures and advertising prominently display the 48 mile (or greater) range without making it clear to the prospective purchaser that there is no way on god’s green earth that the damn thing can pick up the Exxon Behemoth beyond about 17 miles. The diameter of the earth is just too small! It’s an ethics issue to me. At a minimum it ought to be a managing customer expectations issue to the manufacturer.

  6. Larry Brandt says:

    Ben, can I ask you to explain a bit about “pulse compression”?

    I worked on a pulse compression ground radar in the USAF about, …uh, I hate to confess it, about 50 years ago. 1963/64 in fact. The principle was to have a very long transmit pulse (I recall it was about 18 usec) which normally would yield extremely poor range resolution, but a pulse WITHIN WHICH the transmitter frequency would sweep from low to high. The benefit was that the average transmitted power was humongous, and since our transmitter peak output power was 10 megawatts, that was one honking’ sumbitch. The ‘swept frequency’ echo from the target could be decoded by the receiver to yield a highly accurate range resolution. Thus, high peak power, high average power, high range resolution.

    Am I on the right track here, that 50 years later this technology is finally in the hands of the consumer?

  7. abbor says:

    Larry, nobody cares about seeing land areas far away using radar anymore. Distant land areas are seen much better at the chart display, but long range performance is important for a lot of users because they use one of the radar ranges to monitor possible threatening weather cells. When threatening approaching weather cells are detected it’s full speed back to the harbor. The Doppler processing is color coding approaching and divrerging targets making it much easier to find the direction of the weather cell.

    Yes, the principles of the modern pulse compression radar are the same as you describe for the old USAF radar. Correlation is used to get excellent range resolution for the very long swept frequency transmit pulses, but long pulses leave large blind zones. To deal with this the the Halo radar transmits 6 different pulses for each transmission (rotation), one CW pulse and 5 CHIRP (pulse compression) pulses. The CW pulse is used for the shortest ranges (<100m I think), the 5 CHIRP pulses have different pulse lengths all the way to 96us for open Halo, slightly less for Halo24. The returns from the shorter pulses are filling in the blind zones for the longer pulse lengths. The return from all 6 pulses are "stitched together" to form one radar image. The energy of a 96us 25W pulse compression radar is similar to the energy transmitted in a short CW pulse by a 6kW magetron radar.

    When the Navico Broadband radar was introduced (around 2010) it was not feasible to make a pulse compression radar for leisure due to the cost of the transistor used as transmitter. Then FMCW using very low transmit power (about 20mW) and close to continuous transmit pulses had to be used to get sufficient transmitted energy. Now the cost of the high power (25W) transistors have come down, the FPGA's (Field Programmable Gate Array), configurable integrated circuits, used for the signal processing has also been dramatically reduced enabling advanced pulse compression radars like Halo and Halo24 for the leisure market.

  1. December 8, 2018

    […] the rare vessel equipped with four different solid-state Doppler pulse compression radars. With the Simrad Halo24 announced in October, and the Raymarine Quantum 2 introduced last February, all four major marine navigation […]

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