On a sunny day (Mon, 17 Sep 2012 01:13:57 -0500) it happened G. Morgan wrote in :
Yes, it presumes some prior knowledge try this website, the guy build his own GPS stuff, and does a good job at designing too:
A homemade receiver for GPS & GLONASS satellites
On a sunny day (Mon, 17 Sep 2012 01:15:15 -0500) it happened G. Morgan wrote in :
its own code).
the number of wrong
There are in fact several signals on diffrent frequencies, read the spec.
On a sunny day (Mon, 17 Sep 2012 08:30:48 +0300) it happened snipped-for-privacy@downunder.com wrote in :
its own code).
the number of wrong
Partly, as you want to display signal to noise for each individual satellite, you have to identify the satellite in the signal. For that to happen you need to detet its Gold code directly. Now you are full circle :-)
designing too:
Thanks.
If you don't know, why should we tell you.
Rick
sat.
its own code).
the number of wrong
So in reality, you need four independent signal strength signals for the best (geometry) four satellites
You two do make quite a pair.
On a sunny day (Mon, 17 Sep 2012 23:42:23 +0300) it happened snipped-for-privacy@downunder.com wrote in :
? You need 3 sats for a 2D position, and 4 sats for a 3D position solution.
How would a toilet cleaner know that?
Try to tell us, since that is what *you* do for a living.
As for myself...
When I adjust the waveguide output channel of a high power satellite transceiver, my employer is quite comfortable with my understanding of logarithmic progression. Also when I adjust the noise source loop that we pump it with for the test.
You are lost.
As for you...
When you adjust your mop head, be sure to bring it right up next to your face so your crabs and fleas can hop onto it and migrate to new horizons. Good job of spreading the vermin, you immature little retarded characterless honorless bastard. Go back to the kook group, dumbfuck.
^ SOME of your crabs and fleas. We wouldn't want you to go completely without friends.
Three variables require three equations; four, four. Don't forget time.
By the way, Nymbecile, have they given you a toilet brush yet? Or are you still having to use your tongue?
Sadly this has become a kook group, thanks to you.
On a sunny day (Tue, 18 Sep 2012 10:44:15 -0400) it happened " snipped-for-privacy@att.bizzzzzzzzzzzz" wrote in :
Here is partial output from my software GPSPwith teh dealextreme GPS moduke with only 3 sats, it immediately goes to 2D mode:
date and time 2012 9 18 17:7-24 UTC Mode 2D GPS SPS Mode, fix valid pdop 11.8 hdop 11.4 vdop 3.2 satellites used 3 ( 6 3 19 ) satellites in view 12 id 19 * elevation 65 azimuth 166 snr 32 id 11 elevation 62 azimuth 274 snr 0 id 1 elevation 44 azimuth 273 snr 0 id 22 elevation 43 azimuth 63 snr 0 id 3 * elevation 32 azimuth 159 snr 27 id 14 elevation 31 azimuth 98 snr 0 id 32 elevation 31 azimuth 206 snr 0 id 28 elevation 23 azimuth 315 snr 0 id 6 * elevation 22 azimuth 149 snr 24 id 18 elevation 6 azimuth 49 snr 0 id 27 elevation 5 azimuth 13 snr 0 id 20 elevation 5 azimuth 222 snr 0
I left out the location to protect against Miss Iles...
-------------------- As soon as it has signal on 4 sats it goes to 3D mode, so gives altitude too. This is just parsed from the NEMEA data. The low snr is not realy bad, you do not get much more in practice:
[snip]
Well, it's not going to be SINAD since it's not an analog receiver. Your choices are most likely Bit Error Rate (BER), though a BER of 20% woul= d seem completely unusable to me. The other option is C/I+N but again, tha= t's used more for analog modulation schemes (or should be, though some comp= anies think SINAD is acceptable for "digital modulation". These people sho= uld be tarred and feathered. You could write a book about modulation schem= es and their effect on BER, and I'm sure some have. I've never found dBm l= ookup tables to be particularly good descriptors for BER. Your mileage may= vary.
Bars and SINAD and I+N values aside, if the GPS fades too much, there's pro= bably something wrong with the receiver or the placement of its antenna. S= ome antennas are powered (i.e., internal active preamps), so you might veri= fy the batteries are fresh, or it's otherwise powered-up with the correct v= oltage.
Shameless plug: We use a lot of Garmin Montana GPS's (650's and 650t's)for= our field work. Expensive, but perfect for what we do. Of course, as wit= h any early adopter there were some early software glitches; like "Continue= four-thousand one-hundred fifty miles, then make a U-turn", but they squas= hed that bug pretty quick. :)
On a sunny day (Tue, 18 Sep 2012 19:35:15 -0700 (PDT)) it happened mpm wrote in :
If you use ANY GPS receiver that has a NEMEA output, the data we are talking about is standarized in the RS232 'GPGSV' message:
This is the offcial NEMEA standard, for that GPGSV message, it shows an example message and the meaning of the comma separated fields in it.
/* test for SV-GNSS Satellites in View */
/* GSV-GNSS Satellites in View Table B-8 contains the values for the following example: $GPGSV,2,1,07,07,79,048,42,02,51,062,43,26,36,256,42,27,27,138,42*71 $GPGSV,2,2,07,09,23,313,42,04,19,159,41,15,12,041,42*41 Table B-8 GSV Data Format Name Example Description Message ID $GPGSV GSV protocol header Number of Messages1 2 Range 1 to 3 Message Number1 1 Range 1 to 3 Satellites in View 07 Satellite ID 07 Channel 1(Range 1 to
32) Elevation 79 degrees Channel 1(Maximum90) Azimuth 048 degrees Channel 1(True, Range 0 to 359) SNR(C/No) 42 dBHz Range 0 to 99,null when not tracking
each sat.
asignals are
code'.
similar
sat has its own code).
codes, and the number of wrong
Not entirely. The empherides for all the satellites is in flash and can be updated by data from the satellites which are in turn updated by = ground support stations. Since a time solution is relatively in dependant of = the location solution and the satellites found, it can be use to get the empherides data and thus know which satellites to look for the location solution. Of course the receiver remembers the last location it had lock and keeps time while powered off, the empherides is immediately useful in most cases.
?-)
each sat.
asignals are
code'.
a similar
sat has its own code).
codes, and the number of wrong
=46our satellites is minimum for a 3d solution, precision increases dramatically with 6 or more satellites in view. Today having 10 satellites in view is normal out in flat country terrain. Cities and mountains not so much.
?-)
sat.
similar
has its own code).
the number of wrong
Adding GLONASS satellites to your constellation helps immensely. Several chip vendors are adding GLONASS for this reason.
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