I have two old white AS GPS Receivers but do not know if an upgrade in hardware or locator software is needed. One is marked Accessory System with the 737 and one with the 898CSI is instead a GR50. The 737 must be using the old GR16 with unknown accuracy.
I see that the PRECISION, CI, GRP, GPS HS Receivers abound. Of course, all receive overhead satellite (hereafter, Birds)signals.
http://www.humminbird.com/bluewater/Product-Category/Accessories/GPS-Receivers/The 2014 HB Accessory Guide says the GRP works with my 898CSI and will give me 2.5 meter accuracy as long as I have software >6.300.
The HS and CI are for other units.
I take it that antenna height is imperative, as is line-of-sight to the overhead Birds. The stated 2.5m accuracy must be over water with nothing seen 360-deg on the horizon. Also, getting a "3D" enhanced lock for GPS with these antennae is not specified; how many Birds must I see at the horizon on a large lake in order to get the best triangulation--hence, best accuracy. Overhead Birds only yield time and altitude; not so much for positional accuracy. The 898 manual says I am aok if I can see as low as 10-deg above the horizon.
Do I need a better antenna for the 898 to replace the GR50, such as the GRP? Both listed in the 2014 HB Accessory Guide pg 25 and 27 seem to show a difference as WAAS with the GRP, and THAT is only good if one receives the corrected WAAS signal, so that must mean the newer HB [GRP] antennae have an extra or different receiver built inside. WAAS is GPS-like but not the original Bird GPS signal. Does the updated software in my locator now show WAAS Birds on the GPS Diagnostic View? My 898 manual says ENHANCED means I am getting WAAS into the unit (pg 84) but which Birds will be noted in the display as WAAS, to depict their location closest to the horizon for most accuracy; or should I just take the ENHANCED plus positional error and forget the whole thing. It seems the govt website shows the right Birds:
http://www.nstb.tc.faa.gov/RT_WaasSatelliteStatus.htmGPS plus WAAS appears to be an accurate system for location identification, but how about adding in GLONASS? Good article:
http://www.faculty.sfasu.edu/zhangy2/download/WAAS_GLonass_GPS_area.pdfAre there amplifiers made for Humminbird GPS antennae? Seems to me that the incoming antenna signal would be processed and then fed by wire to the locator as some digital format; a homebrew 12vdc amplifier setup would, instead, have merit if an external RF antenna and amplifier combination saw the sky signal, processed it as GPS, WAAS, GLONASS, and them somehow coverted it to the [NMEA?] format to run down a spliced wire into the locator. That would yield a 20% faster lock and maybe a 5% increase in accuracy.
Just overthinking.... 5% won't make the fish bite.