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| author | Eric S. Raymond <esr@thyrsus.com> | 2005-03-21 21:49:52 +0000 |
|---|---|---|
| committer | Eric S. Raymond <esr@thyrsus.com> | 2005-03-21 21:49:52 +0000 |
| commit | d485aab76da9ff8635dce71ea2e3dad1bb0f340e (patch) | |
| tree | 8d4358e864fbe981b9ae2603980f6b8a1849f230 /TODO | |
| parent | 67a7df16183514c69963f28771d5d068854f2cbb (diff) | |
| download | gpsd-d485aab76da9ff8635dce71ea2e3dad1bb0f340e.tar.gz | |
Eliminate GPVTG parsing, it just duplicates inf in GPRMC.
Diffstat (limited to 'TODO')
| -rw-r--r-- | TODO | 24 |
1 files changed, 24 insertions, 0 deletions
@@ -1,6 +1,30 @@ This is the gpsd to-do list. If you're viewing it with Emacs, try doing Ctl-C Ctl-t and browsing through the outline headers. +** Supply geoidal separation for SiRF packet 2 + +Peter H. Dana <pdana@pdana.com>: +> The classic bi-linear interpolation method is published in Table 5.3 +> of DMA TR8350.2 Supplement B (page 5.3) +> +> Np(lat, lon) = a0 +a1*X + a2*Y +a3*X*Y +> +> a0 = N1 +> a1 = N2-N1 +> a2 = N4-N1 +> a3=N1+N3-N2-N4 +> +> X= (lon-lon1)/(lon2-lon1) +> Y = (lat-lat1)/(lat2-lat1) +> Whre +> N1 (lat1, lon1) , N2 (lat1, lon2), N3( lat2,lon2), N4 (lat2, lon1) are known +> geoid heights +> +> Rather than deal with interpolation from a table, most folks use the EGM96 +> coefficients and the formulas for direct computation of N at any point shown +> in NIMA TR8350.2 +> http://earth-info.nga.mil/GandG/tr8350_2.html + ** Hotplug interface problems The hotplug interface works pretty nicely for telling gpsd which |