Thread: Lowrance GPS Question?

Originally Posted by Shellback

We will have to see how deep Don's pockets are. Maybe he could be the guinea pig tester.

Empty pockets....

CarolinaJim, if that's your name. LOL

Originally Posted by FAADAN

I worked with the FAA for many years. I worked on WAAS and GPS design. I retired in '06. As of that time, there was no GPS receiver, even WAAS enabled that could completely eliminate satellite and interference related errors. There is even a worm that wanders around the atmosphere that interferes with GPS accuracy. The faster you are moving, the more accurate it becomes and the slower you are moving the less accurate it becomes. If you are moving extremely slow, you are much more subject to the error. Receivers can average out readings by taking multiple samples and averaging the differences but the error is still there. WAAS uses a stationary antenna at a known location and transmits differential signals that help to compensate for the satellite wobble, drift, intentionally induced errors. (Yes, the military can make GPS totally useless if they want) Even with the WAAS input, there is some error left. Until you can account for such things as reflections, atmospheric interference, electromagnetic interference, and someone getting between the receiver and one of the satellites, you will never have a unit that depends solely on a satellite for it's location.

I worked with Inertial Nav systems in the Air Force and while they are quite accurate, they are mechanical. The usually consist of gyros and accelerometers. Each is a mechanical device and as such is subject to friction and wear.

It appears to me that Humminbird is simply admitting when it is not able to provide precicse data by displaying a circle. Lowrance just makes you feel good.

I went to the moon with nasa apollo. Also went to Trimble school. I know a couple of things myself. I have enough sense to know that there exists program algorithms that approximate rate and time based on last known data. Successive approximations work well in my HDS.

Originally Posted by CarolinaJim

I thought them there fancy HDS's were NEMA 2000 compliant...LOL

I could not figure out how to get to the side scan, down imaging, or 2D sonar screens on that trimble so I threw it away. 7600 dollars and the sonar does not work, junk. lol

It will handle the GPS part only. I talked to Airmar engineer quiet often. Old buddy.

All this crap reminds me of cars and their P codes. ha

Originally Posted by Cane Pole

I went to the moon with nasa apollo. Also went to Trimble school. I know a couple of things myself. I have enough sense to know that there exists program algorithms that approximate rate and time based on last known data. Successive approximations work well in my HDS.

I'll grant you that, they still do not eliminate the error, they simply try to average it out.

Originally Posted by FAADAN

I'll grant you that, they still do not eliminate the error, they simply try to average it out.

That's all I been saying for years. They can make good approximations. Good to have someone with gps knowledge here.

Originally Posted by Cane Pole

That's all I been saying for years. They can make good approximations. Good to have someone with gps knowledge here.

i dont have anything to add. im just sitting here laughing reading this post. good stuff y'all. wait a Minute ,i got something to post.just got back from the murray state game.they won again huray huray!!!!!!!!!!!! woops ,i bet someone here will disagree .oh well

Originally Posted by kosmo

i dont have anything to add. im just sitting here laughing reading this post. good stuff y'all. wait a Minute ,i got something to post.just got back from the murray state game.they won again huray huray!!!!!!!!!!!! woops ,i bet someone here will disagree .oh well

I believe UM had a few of starters out from injuries. Need a redo. It was a good game.

I still have no problems driving up to my waypoints below .5 mph. I don't need a circle on a map to show me where I am "almost" at.