About EM-406 Performance at almost zero speed and comparison with FV-M8

After i was dissapointed by FV-M8, i m thinking to buy EM-406 GPS module.
Before bying it i m interested about it;s performace at very low speeds.
I m aware that this module has a frequency update of 1Hz.

Please if anyone had tested the performance of this receiver to let me know.
I m interested if the lat/long/altitude indications are changing instantly (after 1 sec) when you are moving the GPS by hand for 1 meter in horizontal or in vertical only direction.. this is critical for my UAV quadrotor for altitude holdling and retain in position (just hover) . I dont care if it will be moving in a 10 meters area cause of innaccuracy. I care to have instant indications that my position changed.

I have as reference an old (2.5 years) cheap, bluetooth receiver which i m using it with my smartphone. When i move this receiver for 1 meter or even centimeters i see the indication changing on the screen of my smartphone even in vertical only direction. I m not expecting accuracy but to see variances.

Also if you have to suggest me other intergraded module for this hovering - low speed application (with antenna on board and prefferably at 5Vdc, and UART) please let me know.

Thank you in advance.

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I've datalogged a few minutes of an EM406 that's stationary (see attached file). For the last minute, I moved the module vertically up and down by one meter. Let me know if that answers your question.
Thank you Chris for your response and work :)

As i see this log is in GPRMC protocol which does not provide altitude data. The only protocol that provide altitude (for the vertical moving) as i know is GPGGA if i m not wrong. If you could provide me GPGGA data also i ll be more happy :)
About the horizontal measurements it seems that there is a variation of 7-8 meters (stationary) in lat and long which seems ok.

The other thing that i noticed is that the module gives the course even stationary which is by one hand strange and by the other interesting. Mine (FV-M8) still never show me the course :( and i dont know why...
Dimitris, don't give up on the FM-V8 just yet. If there is any tests you would like me to do for you on my unit let me know.

Also the low speed/stationary performance has been called into question before by Jack Crossfire who is also a member of this site. Let me see if I can find that thread for you.

Edit: Here you go http://www.rcgroups.com/forums/showthread.php?t=742510
Thanks Marty :)

I m keeping testing it and i see that the only way is to work it as 1Hz :(((
At lat/long seems that it could be work for UAV heli position keeping even with some lag.
Chris data showed that lat/long was changing while stationary. FV-M8 seems frozen at this state. The most i worry is for vertical data where i still think that it is not so good. I move it for 1 meter or little more in vertical and nothing is changing :((( Also i dont know why i still didnt get any course direction data. Speed i m getting ok even at 1-2km/h.
I think meter accuracy for elevation might be a little optimistic. Also I beleive the FM-v8 needs to move significan'tly inorder to produce heading information not just 1 meter to the left or right etc.
Sadly, the Adafruit GPS logger app is choking on the GGA sentence (not sure why). I'll have to debug it but don't have time tonight, I'm afraid.
I found some tweaked code that works. Here's a datalogged file with the RMCs and GGAs. I'm just moving the GPS up and down by about a meter for about a minute or so. File attached.
Thanks a lot Chris,
i see that there are measurements for height every second which are differ. This is nice. Not like mine which is almost not changing the height.
Finally it gives me the heading when the speed is more than 7kph. So when walking it doesn;t give you heading even if you walk for 10-20 meters.
What do you suggest for altitude measuring? Barometric sensor i suppose, what else... i m orientated to buy the HP01D (for heights below 1km i think is ok for me and it is 2-5Vdc, what do you think?
Thank you very much for the link.

Finally i believe that FV-M8 is precise, but 1Hz at speeds below 7kph. Also you cannot be based at the altutude data for hovering because it has big lag and you have to move a lot to have variance in indication. It is really 5Hz at speed >7kph, precise and very sensitive so it is good for airplane.

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