[CA] [CA11] Axiom 7 satellite acquisition

[bartyb]

How long should my Axiom 7 take to acquire satellite data?
Currently it seems to take 20-30 minutes, I'm sure it used to be quicker with LH2, now on LH3.4 qnd have downloaded 3.6 in the vain hope that it may improve matters

[Chuck - Raymarine - Moderator]

Welcome to the Raymarine Forum bartyb,

Axiom MFDs have never been compatible with LightHouse II software. These MFDs have been exclusively designed to operate with LightHouse 3 software. It is further recommended that these MFDs be maintained with the latest software update (v3.6.32 at the time of this response).

Please click here to view a FAQ addressing when an external GPS sensor would be recommended. Should the MFD be installed in a location affording it an unobstructed view of the skies overhead, then a GPS position FIX would typically be acquired within 2-3 minutes. If the MFD has been installed in a location affording it an unobstructed view of the skies overhead and it is taking longer than than this, then it would be recommend that the MFD be sent to Raymarine’s Product Repair Center to be bench checked / serviced.

[Mike_EE]

Hi Chuck -

I read this some interest as I was on the verge of making my own post on this topic.

I have an Axion 9 RV (LH v3.6.32), and I'm seeing longer-than-expected Time To First Fix (TTFF), though not 20-30 minutes - more like 2-5 minutes. This is longer than other units that I've owned in the recent past that would provide TTFF within 10-30 seconds after fully booted.

I keep my boat in a metal boathouse, so there is no GPS signal available until I move outside and then there is an immediate open view of the sky, which gives me a chance to monitor this behavior every time I use the Axiom. The behavior is the same if I cycle power with a clear view of the sky, so what I think is happening is that the LH3 software is not caching the GPS almanac at shutdown and the Axiom has to perform a GPS "cold start" every time it's turned on.

The competitive units that I've used in the recent past, and indeed most other GPS-equipped devices, will retain almanac and other relevant data at shutdown which allows them to GPS "warm" or "hot" start and provide a fix almost immediately.

Is this expected behavior for the Axiom and/or LH3?

Thanks,

Mike

[Chuck - Raymarine - Moderator]

Welcome to the Raymarine Forum Mike,

In fact Axiom MFDs have been designed to retain the GPS almanac. GPS receiver sensitivity of the Axiom (touchscreen only) MFDs is lower than that of other Raymarine MFDs and Raymarine's external GPS sensors. A couple of minutes would be typical, but 5 minutes would seem a bit long for acquisition for a MFD which has been installed in a location affording it an unobstructed view of the skies overhead. If started with such an obstruction overhead or the MFD has been switched OFF after it has lost its GPS position FIX such as may occur when the boat returns to dock, then the MFD may take longer than normal to acquire a GPS position FIX. That said, I'll submit a request to our engineering team to test that the almanac is being retained between power cycles.

[Kr7]

Hello

Was there any changes in last two updates of LH ?

I'm using Axiom7 from April, it's mounted in 'normal' sailboat, until august update I did'nt observe any problems with fix. I start Axiom, and in about 30s-1m it was it ready to work.

After August update i observe that - after i start axiom morning in dock, where i ended yesterday, sometimes, after 5 minutes it's still not ready to work - "no gps fix", once it was 20 minutes when it was not ready. When i do manual restart and go to "GPS fix" tab - it usual helps.

I didnt have any issues like this before this update. What can be wrong ? Something in LH, or my Axiom is starting to dying ? :/

[Chuck - Raymarine - Moderator]

KR7,

Should the MFD be installed in a location affording it an unobstructed view of the skies overhead (bimini tops may be ignored, while hard tops do not meet this requirement) and the MFD be unable to acquire within 6 minutes and/or maintain a GPS position FIX, then it would indeed indicate a problem with the MFD's internal GPS sensor necessitating that it be sent to Raymarine’s Product Repair Center to be bench checked / serviced. Alternatively, the MFD may be interfaced to an external GPS sensor supporting NMEA 2000 communications (ex. Raystar 150 GPS Sensor, etc.).