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Heading Sensor, 3 axis vs. 2 axis rate gyro?

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This is an e-mail exchange I have had with Airmar. I am trying to decide if I will suffer and how much if I buy the PB200 with the wireless weather features because its gyro is only a two axis. I certainly put a premium on accurately knowing my position. The primary reason for the purchase is to buy a heading sensor to enhance my radar's capabilities and work with an autopilot.

Will your PB200 or the GH2183 do the same job that I was expecting from the H2183? I would like the added functions of the weather information if the heading sensor function is going to be the same in my application for both sensors. I will be using the heading sensor to talk to my Garmin HD radar on the screen of my GPSMAP 3210.

Can you clear this up for me please before I make my purchase.

While they are very similar the H2183 uses a 3 axis rate gyro and the PB200 uses a 2 axis rate gyro. This difference will make the H2183 more stable in dynamic conditions.>

I want a stable heading sensor, right? How stable?

3 Replies

  • The 3 axis unit provides better rate of turn information to the A/P, etc. While we tend to think of a vessel sitting on the water as being limited to 2 planes of motion, it does in fact exist in 3 planes and further complicated by the degrees of freedom exerted by its own effort to move through that water. As systems demand 10Hz and even 20Hz update rates, the 2 axis gyro product becomes a relic. (Hint: try to find a 2 axis gyro integrated circuit on the market today in manuf. quantities.)

  • PB200 heading sensor is motion corrected and gives great results compared to a flux gate.

    See this article from Ben

    However, it is for powerboats only. On top of a sailboat mast there are limits to how well it works in rough seas.

    Did you mean ultrasonic weather feature? I am not aware of any wireless weather feature on a PB200.

  • Without actually looking at the source code, I'd be surprised if the GPS location data is in any way even aware of the instantaneous heading, pitch, roll, etc. being indicated by the other sensors in the unit. The GPS location is from something like a SiRF IV integrated circuit and the quantities for this product probably do not justify any code revision to the chip. I submit there is a 2K hub in the unit that is metering out NMEA sentence from the subsystems incorporated.