HobbyKing.com New Products Flash Sale
Reply
Thread Tools
Old Jan 02, 2012, 09:18 PM
Registered User
yzguy's Avatar
Florida
Joined Mar 2007
826 Posts
since the LOS (or DIST) is already just distance, the angle to the plane would be easy to calculate. Is this in there somewhere already?
It would be nice to keep the plane at a certain angle to keep a good signal to the plane.
yzguy is offline Find More Posts by yzguy
RCG Plus Member
Sign up now
to remove ads between posts
Old Jan 02, 2012, 10:51 PM
Suspended Account
United States, FL, Maitland
Joined Apr 2011
2,109 Posts
Quote:
Originally Posted by yzguy View Post
since the LOS (or DIST) is already just distance, the angle to the plane would be easy to calculate. Is this in there somewhere already?
It would be nice to keep the plane at a certain angle to keep a good signal to the plane.
i did this before and calculated a minimum altitude to maintain 15 degrees in order to get good reception on a patch antenna.

http://www.youtube.com/watch?v=-sa7w4pbYv0
chatch15117 is offline Find More Posts by chatch15117
Reply With Quote  (Disabled)
Old Jan 02, 2012, 11:02 PM
Suspended Account
United States, FL, Maitland
Joined Apr 2011
2,109 Posts
obviously simple trig, but here is the work done for you



simply modify layout.h to move stuff and add/remove stuff
chatch15117 is offline Find More Posts by chatch15117
Reply With Quote  (Disabled)
Old Jan 03, 2012, 12:25 AM
Registered User
United States, TX
Joined Oct 2010
331 Posts
Took some poking around but I got what I want. Just had to comment out a couple lines in layout.h
Slaphappysamy is offline Find More Posts by Slaphappysamy
Reply With Quote
Old Jan 03, 2012, 01:15 AM
Expert
Joined Mar 2007
83 Posts
Quote:
Originally Posted by highviz View Post
if you could direct me to the right file location to change...
looks like we need comment 2 lines in gps-nmea.h
gGpsLastData.speed *= 463;
gGpsLastData.speed /= 250;
redsonic is offline Find More Posts by redsonic
Reply With Quote
Old Jan 03, 2012, 03:03 AM
Registered User
Joined Mar 2009
1,076 Posts
Thanks Redsonic - must have had tired eyes last night, as I could not find those lines, despite them being well commented.

- I'll take a drive with the unit today, to verify that we are really seeing a 1.85x error, before commenting those lines out. Rough calculations from time over distance during yesterdays flight seem to support it though.

Malcolm
highviz is online now Find More Posts by highviz
Reply With Quote
Old Jan 03, 2012, 04:59 AM
Up up and away!
FpvKiwi's Avatar
Sweden
Joined Oct 2010
700 Posts
Quote:
Originally Posted by yzguy View Post
since the LOS (or DIST) is already just distance, the angle to the plane would be easy to calculate. Is this in there somewhere already?
It would be nice to keep the plane at a certain angle to keep a good signal to the plane.
Angle is useful but maybe arctan is expensive for the poor little AVR to calculate. In such case, glide number or whats-it-called should be good enough; 100 * height / dist
FpvKiwi is offline Find More Posts by FpvKiwi
Reply With Quote
Old Jan 03, 2012, 05:38 AM
RC pilot by soul
Israel
Joined Apr 2005
2,472 Posts
Hey guys,

im trying to make a GPS unit from a LASSEN-IQ module (trimble) + Trimble antenna.

im wondering, do i need just the GPS antenna (on the right) or the complete antenna with amplifier (left) ?

please advise.
i3dm is offline Find More Posts by i3dm
Reply With Quote
Old Jan 03, 2012, 10:38 AM
Registered User
Joined Mar 2009
1,076 Posts
I found a bit of private road and mapped the G-OSD II recorded speed against my satnav this afternoon:-



The speed display rolled over above 255 - but that won't be a problem for most!

Results are close enough to the predicted 1.85 x error, so I'll comment out the existing multiplication factor and see what happens....

Malcolm
highviz is online now Find More Posts by highviz
Last edited by highviz; Jan 03, 2012 at 10:48 AM.
Reply With Quote
Old Jan 03, 2012, 12:59 PM
Registered User
Joined Mar 2009
1,076 Posts
That worked for the instantaneous speed. Now looks to be within 1 -2kph at normal flying speeds. Plenty good enough for me

The recorded stats however, are showing high figures on both speed and altitude. Of course I was not very scientific about things, so had changed the refresh rate to 4hz at the same time as making the speed changes. Guess I'll have to step back on one of those changes to narrow down the cause......

Malcolm
highviz is online now Find More Posts by highviz
Reply With Quote
Old Jan 03, 2012, 04:30 PM
Registered User
yzguy's Avatar
Florida
Joined Mar 2007
826 Posts
Quote:
Originally Posted by FpvKiwi View Post
Angle is useful but maybe arctan is expensive for the poor little AVR to calculate. In such case, glide number or whats-it-called should be good enough; 100 * height / dist
yeah, I was thinking fuctions like that might be to much, but actually now that I think about it, once you come up with an angle, like say 15 degrees, then the ratio of height to distance is constant for that angle (right? or am I remember this stuff wrong). So I can get that number, and just make the altitude blink if the ratio is below that number. The actaul angle does not matter, just if I am above or below it. This would be easy to add, and I can add comments for a few different ones. (and a minimum distance, who cares if you are less than 15 degrees LOS if you are 50 feet away)
yzguy is offline Find More Posts by yzguy
RCG Plus Member
Old Jan 03, 2012, 04:34 PM
Registered User
yzguy's Avatar
Florida
Joined Mar 2007
826 Posts
Quote:
Originally Posted by chatch15117 View Post
i did this before and calculated a minimum altitude to maintain 15 degrees in order to get good reception on a patch antenna.
yeah, that displays the minimum alt.... I was thinking more of an alarm, but displaying the number might be cool too.

another thought was just making a hard coded lookup table for the ratio of hight to distance, say in 5 degree increments. Not as accurate, but probably close enough.
yzguy is offline Find More Posts by yzguy
RCG Plus Member
Old Jan 04, 2012, 03:34 AM
Registered User
Canberra, Australia
Joined Jan 2008
60 Posts
Quote:
Originally Posted by after.burner View Post
Got my E-OSD to work! The reason for my problems: GPS Checksums were invalid 99% of the time @ 9600 baud. I switched to 4800 baud and everything works like a charm. Here is a patch that will make the satellite symbol blink if the OSD receives GPS data with wrong checksum.

Also I switched to 2 hz update rate on GPS and OSD. Judging from my ground test this is way more reactive than 1 Hz. I'll try to post a flying vid soon.
Nice patch!

I mentioned in my last post that I am using my GPS at 38400 (I don't get the choice to change that as I'm just sucking a feed going to my autopilot who is in charge.)

I've finally done some flying and while it does technical seem to work (numbers seem reasonable), it is very slow and sometimes does not update LOS, ALT etc for many seconds. Perhaps I still have transmission errors too but enough packets get through to make it kinda work. I'll try your patch and watch out for the blinking icon.

Perhaps there are still some serial bugs lurking in cl-osd?

Dave
davico is offline Find More Posts by davico
Reply With Quote
Old Jan 04, 2012, 06:30 AM
Up up and away!
FpvKiwi's Avatar
Sweden
Joined Oct 2010
700 Posts
Quote:
Originally Posted by yzguy View Post
yeah, I was thinking fuctions like that might be to much, but actually now that I think about it, once you come up with an angle, like say 15 degrees, then the ratio of height to distance is constant for that angle (right? or am I remember this stuff wrong).
Yes, angle and height/dist ratio are equivalent. The problem with 100*height/dist is that it might become arbitrarily large if flying overhead. It gives the height you'd have if dist is 100m so maybe just write "99" or some other character if the angle is above 45 degrees.
FpvKiwi is offline Find More Posts by FpvKiwi
Reply With Quote
Old Jan 04, 2012, 07:36 AM
RC pilot by soul
Israel
Joined Apr 2005
2,472 Posts
do the last versions of CL-OSD come with compass already ?
anyone got some videos with the compass on ?
i3dm is offline Find More Posts by i3dm
Reply With Quote
Reply


Thread Tools

Similar Threads
Category Thread Thread Starter Forum Replies Last Post
Build Log Super OSD ($90): Open Source Graphic OSD: Vario, 6xADC, Games, Datalog, Dual Video tom66 FPV Equipment 1928 May 24, 2014 11:07 AM
Discussion Open Source Remote Control System (OSRC) Gizmoman31 Radios 152 Apr 24, 2012 06:01 PM
Discussion Open source OSD for FPV UFO_MAN FPV Talk 75 Sep 07, 2011 02:03 PM
Question Open Source Octo Design Available...Looking for someonw who can cut a copy for me... Schatham421 Multirotor Talk 14 Apr 12, 2011 05:22 PM