9-Axis Heading Sensor Cores

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Ian_Rob

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To stabilise radar and charts on Axiom MFD’s, Raymarine recommend their 9-axis sensor cores (EV1, EV2 or even the AR200). I am sure these are very good bits of kit but they are quite expensive. Are there generic heading sensors that would work equally well but cheaper?
 
Ian_Rob said:
To stabilise radar and charts on Axiom MFD’s, Raymarine recommend their 9-axis sensor cores (EV1, EV2 or even the AR200). I am sure these are very good bits of kit but they are quite expensive. Are there generic heading sensors that would work equally well but cheaper?
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The opensource pypilot autopilot uses MPU9255 >
mpu9255 inertial sensors raspberry pi
Possibly the same chips raymarine use, dunno.
Might be a bit geeky to get the seatalk sentences created though, openplotter/signalk running on a raspberry pi will read and write N2k out of the box with a can adapter but maybe raymarine use non standard messages. Openplotter has software which takes care of the calibration which is continuous . Refresh rate is 10Hz from memory.
 
Thankyou. The 9-Axis Heading Sensors from all the name manufacturers seem very expensive, typically retailing at between £600 -£1000. Raymarine’s AR200 is a bit less. There must surely be more to them than $14 inertial sensing chips?
 
Ian_Rob said:
Thankyou. The 9-Axis Heading Sensors from all the name manufacturers seem very expensive, typically retailing at between £600 -£1000. Raymarine’s AR200 is a bit less. There must surely be more to them than $14 inertial sensing chips?
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No idea about what's in them, but must be a lot of design , software and tooling for not that many sales. I have one of the MPU boards, not really had the chance to give it a full on ocean test but seems great so far, though there are a lot of duds out there apparently. The PyPilot software which talks to the mpu & does the auto calibration was written by a guy who rewrote a lot of OpenCpn, world class programming for free ? The chips used are commonplace in drones these days, maybe raymarine got stuck with older tech before this chip was available, the sensors market moves fast thesedays. MPU-9250 | TDK
 
Ian_Rob said:
Thankyou. The 9-Axis Heading Sensors from all the name manufacturers seem very expensive, typically retailing at between £600 -£1000. Raymarine’s AR200 is a bit less. There must surely be more to them than $14 inertial sensing chips?
Click to expand...
Yup, a few man-years of product development and testing.
 
Ian_Rob said:
To stabilise radar and charts on Axiom MFD’s, Raymarine recommend their 9-axis sensor cores (EV1, EV2 or even the AR200). I am sure these are very good bits of kit but they are quite expensive. Are there generic heading sensors that would work equally well but cheaper?
Click to expand...

What plotter and radar do you have ?

Do you use the plotter with a radar overlay ?

Do you have an autopilot ?
 
Where do they get 9 axes from? If it's a heading chip it is on one axis only!
I know Raymaribe are highly inventive on prices, I hadn't realised they'd developed hitherto unknown multi-dimensional physics too.
 
Slowboat35 said:
Where do they get 9 axes from? If it's a heading chip it is on one axis only!
I know Raymaribe are highly inventive on prices, I hadn't realised they'd developed hitherto unknown multi-dimensional physics too.
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It isn't just a heading chip. The sensor does heading, roll, pitch and yaw.

When used with an appropriate autopilot it will predict the movement of the boat and the autopilot will react earlier. All of the big names use them with their autopilots and they are all similar money. Expensive.
 
PaulRainbow said:
What plotter and radar do you have ?
The Plotter is an Axiom + and the scanner is a Quantum 2. Nothing yet installed.

Do you use the plotter with a radar overlay ?
I definitely want to be able to overlay radar on the chart and to be able use the Quantum’s MARPA and ARPA funtionality so I am gong to need a heading sensor.

Do you have an autopilot ?
Yes - an ST 6002.
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Slowboat35 said:
Where do they get 9 axes from? If it's a heading chip it is on one axis only!
I know Raymaribe are highly inventive on prices, I hadn't realised they'd developed hitherto unknown multi-dimensional physics too.
Click to expand...
the MPU is 3 axis magnetometer, 3 axis gyro & 3 axis accelerometer. 1 axis would be the best compass ever...... ;)
 
GHA said:
And are more than willing to pay the massively more expensive options.
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Not sure they have a choice, unless you know of an off the shelf 9 axis heading that's cheap ? I don't.

Perhaps there's a market for you here, if you can make something from that $14 board that would just plug in to N2K.
 
Ian_Rob said:
The Plotter is an Axiom + and the scanner is a Quantum 2. Nothing yet installed.

I definitely want to be able to overlay radar on the chart and to be able use the Quantum’s MARPA and ARPA funtionality so I am gong to need a heading sensor.

Yes - an ST 6002.
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You're right, you will need a heading sensor, but for what you want to do you don't need a 9 axis one, your current system will not make any use of roll, pitch or yaw, all you need is heading.

Your autopilot has a heading sensor and it will output that over Seatalk. If you fit the Raymarine Seatalk to STNG converter kit the autopilot should put heading data onto the network. It will also make any ST data available too, depth, wind, speed etc.
 
PaulRainbow said:
You're right, you will need a heading sensor, but for what you want to do you don't need a 9 axis one, your current system will not make any use of roll, pitch or yaw, all you need is heading.

Your autopilot has a heading sensor and it will output that over Seatalk. If you fit the Raymarine Seatalk to STNG converter kit the autopilot should put heading data onto the network. It will also make any ST data available too, depth, wind, speed etc.
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Thanks Paul. I had been led to believe that the 12 year old fluxgate compass I have, wouldn‘t be up to stabilising an Axiom display for MARPA/ARPA purposes and though it would to some extent stabilise the radar it is likely that there would be a slight mismatch between the radar returns and charted objects. It will be great if I don’t have to buy an EV1 or similar.

I picked up a new Seatalk/SealtalkNG converter on eBay a few weeks ago.
 
Ian_Rob said:
Thanks Paul. I had been led to believe that the 12 year old fluxgate compass I have, wouldn‘t be up to stabilising an Axiom display for MARPA/ARPA purposes and though it would to some extent stabilise the radar it is likely that there would be a slight mismatch between the radar returns and charted objects. It will be great if I don’t have to buy an EV1 or similar.

I picked up a new Seatalk/SealtalkNG converter on eBay a few weeks ago.
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You might ave a 5hz sensor or a 10hz, depending on the exact autopilot you have, the "ST6002" is only the controller. I'd try it and see, if it isn't up to the job just fit a faster sensor, such as the Autonnic one above, fraction of the Raymarine 9 axis sensor.
 
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