Why US Gov. induces errors in the GPS data? I mean... the forces that don't like us... If they were to bomb us I'm kinna thinkin' it ain't gonna be bottle rockets and blackcat firecrackers.... What they'll be sending 3'... 30'.... 300'.... hell... couple of miles ain't gonna make a lot of difference if it get's here. Things that make you go Hummmmm?????
Maybe so some bad actor can’t determine the exact position of the satellite in space, and shoot it out of the sky?
2016 Ranger 1850 LS Reata / Merc 150 4s / SmartCraft / Lowrance HDS Carbon SS3D
I think you might need to update your information. Selective Availability was turned off in 1996 (best thing Bill Clinton did...).
There are no deliberate errors in the system since then. GPS is accurate with the current recreational units to roughly 10' or so (3 meters) with WAAS enabled.
Dual frequency receivers (like most newer iPhones, Garmin units, etc) use both the US system (GPS), and/or the Russian system (GLONASS), and/or Galileo (EU system). The combination of multiple sources can produce an average 3' (1 meter) placement.
They also ended the military draft in 1972 as well...just saying <LOL>!
They don’t. Errors are a result of satellite position geometry, atmospheric conditions and the laws of physics. COCOM limits on speed and altitude are built into receivers to make it difficult to use them to build ICBMs.Originally Posted by yupitsme
If you have integrity, nothing else matters. If you don't have integrity,
nothing else matters.
It amazes me that my I-Phone, while not inexpensive, has better GPS technology than my $3000 MFD. When I was setting up my HDS Live a few months ago, I thought I saw GLONASS show up in a menu somewhere. Do you know if these units can be set up to use it? Thanks.
What makes you think that Phones have better GPS Technology?????
The GNSS in our graphs and external P-1 has advantages over a phone, better antenna just to start. Still all civilian GNSS systems currently available are at the mercy of the technology.
The software running behind the scenes can make it "Appear" a phone is more accurate, for example google maps, will lock on to the west bound lane 4lane interstate, when I am actually on the outer road on the far side of the highway bypassing a wreck.
Don't miss understand me though, GPS accuracy has come along way. But no where near enough accuracy to pinpoint a 1x1 rock on the bottom. This is why I always correct someone when the question comes up on mounting a P-1 and it seems the first response is "as close to the transducer as possible" with no mention of checking for magnetic interference first.
That is exactly correct...Excellent points.....Not to mention my favorite inaccurate mess created on the boat...Close to the transducer is useless if it is pointed off to the side, behind or way in front.....Point being the angler most times has NO CLUE where his transducer is pointing...what is it seeing and where is the target...really?? Therefore wrongly assuming the picture on the screen is directly below the transducer in a 6 foot circle, ( 2D 18' depth)...prob a huge mistake...where they THINK it is...can easily be 20 feet off, likely more. So they mark the screen spot and it is far off where they think the mark is...Not to mention all of the normal errors mentioned above.
In my seminars I used to hit on this and not until I get to the whiteboard and draw it out does it make any sense to most guys...so I quit trying here. :))))
Here is the whiteboard example...Stand on a 10 ft ladder with a sharp focusing flashlight...hold it up high, 12' or more....place a piece of tape where straight down light spot is....then tilt it forward 10 degrees or so... and mark the light spot again...that is likely the BEST scenario but on the water it could be more or less, AND right or left it is also far off by varying amounts so. Totally unknown in a large area depending on actual depth...can be WAYYY off.
UNLESS the transducer spot is determined and accurate...everything else could be WAY WAY off in different directions...a mess of inaccurate info.....thus a lot of target location problems are actually installation caused issues. So, line up your transducer so you know what it is seeing. That would help a lot.
Impossible if you have a glassed in bilge transducer which little chance it sees straight down under the point 1/transducer mounting....the reason I always suggest transom mount such as HST-WSBL or other transom brackets...which are easily adjustable for front/back and side to side adjustments. GL
Tommy
Prostaff
Lowrance/Navico
Last edited by prostaff1; 07-16-2019 at 06:17 PM.
Interesting explanation, but couldn't you solve this simply with a 360 unit? Especially for finding angles to target structure? It seems a lot less time consuming then searching around for a great piece of structure you just found. I know a few crappie guides that still use spotlightscan just for this reason.
Last edited by jjjaymmman; 07-16-2019 at 10:40 PM.
Solix 12 Gen2 Mega+ SI, Helix 7 DI G3, Helix 10 G3N SI +, Helix 9 G3N SI +.
Upgraded to Mega imaging from a HDS-12 Carbon
Information updated....
I suppose you could but honestly there are a multitude of ways to achieve more accuracy. That is one. My opinion is that the angler should set up his main transducer, transom mount, using the same method as a drop shot on the bow using the TM transducer. That is extremely pinpoint accurate and a LOT of pro tournaments have been won doing exactly that. This very "iffy" method of transom or bilge ducer mounting starts with a wild guess, at best, of where it is seeing. I have 7 transducers on my boat and excellent electronics BUT, I still use the old floating plastic markers with line and weight a lot. (keep them next to driver seat) See a target on screen at idle and throw it back over the transom. Pretty close :))
Lowrance used to sell a dual suction cup transducer transom mount. Stick it on at the ramp and you were looking close to straight down...for the flasher screen.:))
Antique now (I still have a new one in its box)....but sometimes simpler may be better. I do not disagree on either 360 or spotlight as both are used by some guys with great success. Not a cop-out but different methods for different anglers... and still the best is what works for him. Again I think the huge mistake and gremlin in finding marked targets is the angler marking per the screen and the mis-aligned transducer is the culprit making it difficult. Think drop shot off the transom to set it up. 2 cents:)
Tommy
Prostaff
Lowrance/Navico
Last edited by prostaff1; 07-17-2019 at 07:55 AM.
I put this in another thread but it is relevant here too.
2014 X19
2014 200 SHO
Might want to read this. Electrons in the air don't have much to do with it. It is definitely worth considering, as mentioned in this link, that very accurate survey work is done using GPS now days, so it is possible to get extremely accurate, it's all about the equipment.
https://www.e-education.psu.edu/geog160/node/1924
https://www.e-education.psu.edu/geog160/node/1925
The second link, section 5.4, talks about how to reduce error. I'm not sure how practical some of that is for on water use, but I think these links give a pretty clear idea of what causes the error and how a person could go about correcting it, and knowledge is power. I think in practical terms, we are primarily limited by the tech in GPS MFDs for fishing.
Kevin | 2000 Champion 191 | 2000 Yamaha OX66 200hp
I'm not gonna argue what causes the error(I do think the guy in the vid was talking way out of his lane on the cause) but according to your links, we have to buy more and better equipment to get better than the 7 meter accuracy that WAAS provides. I posted this up because that it shows error and how you can look it up on your unit. If any one wants t check this, pull your boat out in your driveway and turn the unit on. Pull up the map and zoom all the way in. Give it 30 minutes and look at the trail it leaves. I think RMP did this on video one time but I cant find it.
2014 X19
2014 200 SHO
Having to still use markers with your current setup causes concern for customers who don't have as much invested in units like you do; and then still needing the use of an analog means to estimate a targeted area. Whereas using a 360 or spotlightscan would eliminate all that guess work.
I also don't see the need of "7 transducers" on a boat? Why 7??? Are you needing a backup to the backup to the backup?
Solix 12 Gen2 Mega+ SI, Helix 7 DI G3, Helix 10 G3N SI +, Helix 9 G3N SI +.
Upgraded to Mega imaging from a HDS-12 Carbon
You have no idea of what you are referring to. I have 5 on transom. Airmar Tm 150, SS3D, two HST-WSBL and Vexilar sonarphone...TM 150 and LSS-1 on TM...SO I typically run 4 screens and do a lot of product comparing and switching...So PLEASE do not assume you know anything about what I use or need. I was making a point that to eliminate all of the GPS mumbo stuff one way is dependable...markers used for decades with success. I do not need your unknowing evaluation of anything I do or what I use. I have live 16, Carbon 16, Carbon 12 and Gen 3 HDS 9....LSS-2 and 3 in 1 on the shelf. ...so any software, any version can be tested as I wish. Even have still operating "Green Box" flashers and a spotlight scan if I choose.....No intention of wasting my time explaining what and why I use different transducers for different purposes...Trust me...after 40 years of flashers, to paper graphs, all LMS, HDS up to Live units....I do NOT need your advice or help in any way so your "assumptions" are just what the name implies.
Tommy
Prostaff
Lowrance/Navico
What assumptions? You clearly stated above with an all caps "BUT" and "a lot" in your statement:
"I have 7 transducers on my boat and excellent electronics BUT, I still use the old floating plastic markers with line and weight a lot."
Seems pretty clear that's not my assumption but a response to your statement. Furthermore, I offered no evaluation, just questions. But at least you've explained why you have 7 transducers installed. So, can you find structure with your spotlightscan without the need for markers?
Solix 12 Gen2 Mega+ SI, Helix 7 DI G3, Helix 10 G3N SI +, Helix 9 G3N SI +.
Upgraded to Mega imaging from a HDS-12 Carbon
I dont believe spotlightscan was mentioned as one of the 7 transducers, I read TM 150 and LSS-1 on the TM, the other 5 on the transom.
2011 Tracker PT 175 TF
2011 Merc 60 ELPT 4S
He also mentioned he has a spotlightscan in addition to those. Although it's probably not installed all the time.
But when your tournament fishing in this summer heat, you may hit 10 to 20 spots in one day while focusing on specific structures. You lose valuable time dropping markers and picking them up between spots. You may even spook the fish each time. However, if you use a general reference waypoint and come back to that spot with a spotlightscan or a 360, you expedite your execution with targeted casts instantly instead of guessing. Or rescanning. Or worrying about your present GPS error. Or the price of tea in China. You could possibly use livescope or livesight to find that specific structure. But that's like using a flashlight versus a floodlight in comparison.
Here's a great example:
Solix 12 Gen2 Mega+ SI, Helix 7 DI G3, Helix 10 G3N SI +, Helix 9 G3N SI +.
Upgraded to Mega imaging from a HDS-12 Carbon
Spotlight scan is on the shelf for loaning out or testing. I do not need it. The boat is wired for varied testing also using all dedicated modules and using an NEP to make it easy if needed. Multiple Enet cables to additional four locations as well as NMEA. All electrical thru the Blue Sea system. I am set up for using and testing since guys expect me to give good accurate info only available from hands on. Spotlight worked well for me...I did not like the "steering smooth and steady" of it for the best results...but it did its job and "IF" I chose to dedicate some time to really get used to it I have no doubt it would be very good. Thinking most guys who tried it also did not put the time in to get used to it. My guess. Technology was fine.
I am having less and less time for the testing and experimenting so I have not been posting anything about it. Lots of other guys here posting good information so figure mine is not needed as in most cases they have it covered well. The comment on the plastic weighted markers was a point that sometimes simpler is better, even that old supposedly out of date technology. It is dependable, no crap about GPS and offsets yada yada. It works well and drop it and recircle back and mark it with the GPS if you insist. :))) Use two or three to mark a ledge shell bed and fish it!! Only negative is that everyone going by can see your line..why I paint all of my markers black. :)) Can't leave them there thus GPS marking is fine as it will put you close tomorrow and drop or not at that point. What is best and proven for me...maybe not the best for others...who cares if it works. Right ??
Tommy
Prostaff
Lowrance/Navico
Yup, it's a workable method, just not ideal during a tournament if you're on the move hitting multiple deep water structure spots - very common during this summer heat.
I followed a lot of the elite pros around on Lake Guntersville a couple of week ago. Didn't see anyone drop a marker. However, I had the pleasure to speak with Chris Zaldain. He explained how using his 360 imaging provided the angles needed to cast a flutter spoon right outside the grass line edge. I found that very useful and I think others would greatly benefit from this method. Which is probably why the mega 360 earned an iCast award this year.
Again, it seems 360 and spotlightscan provide a time saving alternative to combating these waypoint marking errors you've addressed. I don't forsee you using this, but it's excellent information for others.
Solix 12 Gen2 Mega+ SI, Helix 7 DI G3, Helix 10 G3N SI +, Helix 9 G3N SI +.
Upgraded to Mega imaging from a HDS-12 Carbon
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