I am trying to find out whether there is a hand-held GPS unit that would be precise to a fairly fine level. I tried searching but either this specific question hasn't come up here yet or I was unable to find it. I've been researching for several days now and I have figured out that I will likely need what I believe is called a "Dual-Band" model. I'm looking for a level of precision on the order of One Inch or better. Horizontal accuracy is not as important as vertical accuracy. I want to be able to measure elevation with reasonable accuracy specifically for the purpose of installing drain tile or pipe without having to break out a Transit. So essentially, I am looking for a level of accuracy that is close to what is needed for Survey work and hopefully without a prohibitive cost. Cost range? Something that costs a few hundred dollars is fine. Something that is above </body>,000 is getting into the range where it's probably not worth it. Thank you in advance for any help you are able to give me, even if it's just to tell me that what I am looking for does not yet exist.
