As a followup to my own posting below (PM2 L2 Tracking?), I'm curious to learn whether the carrier phase and SNR raw data displays for files collected by Locus receivers show values for L2. Any of you Locus folks out there care to take a look and comment?

Thanks.


Modified By Jim Frame on 11/18/2001 at 1:58 AM

Jim
I saw your other posts and am just as intrigued as you, as to what raw data these GPS units can output. It would open up a whole new world of opportunity.
But I think you have found the limit of the "average surveyor's" knowledge on GPS. This is something that only Alfred Leick, or the manufacturer, would be able to answer.
It is similar question to: "getting L1 data out of a Garmin GPS, and then knowing what to do with it." Maybe some mortal, between scientist and surveyor, will answer. But while I'm waiting, I think I will do the Alfred Leick internet course, and then will be able to tell you in 4 years!!!

Modified By jon stratton on 11/18/2001 at 3:57 AM

Jim,

Haven't seen obvious L2 data show up in Solutions while processing.

Locus does produce a file, iono, but it is not apparent what it is used for, if at all. there is probably some documentation on this file somewhere, I just haven't run into it.

Jimbo

I seem to remember Bill Martin saying the iono file was unused and for "future" enhancements...

I have not seen any L2 data in processing.

Steve G

In another thread (Update handheld GPS to Magellan Map 330?), Phillip Stevenson wrote:

John, some of the guys at work have been doing experiments with cables and connectors to do things with the ProMark2 that are outside the box of what it is being sold to do.

If you have the technical proficiency to create cables and operate software that is outside the realm of what tech support is going to do for you then the Map 330 or ProMark2 will let you go there. I was amazed at what one of the guys put together and was doing with the box. Is it for sale? Heck, no. What they cobbled together was so fragile it probably would not make it through packaging. This is for the tinkerers and experimenters only.

But your first comment was that it would not do some things you wanted to do. Well, it might do more than you think.

Phil, do your cryptic references above have anything to do with turning the PM2 into a dual-frequency unit?

Isn't the iono file from the Locus units the "estimated" ionospheric correction needed for the L1 solution? Seems that subject came up in all my recent questioning about solar effects on the ionosphere. L1 uses an estimated value whereas L1/L2 uses the differential computed by dual frequency comparison. Since you still have to account for some correction of ionosphere I'd think that's what the iono file is. I download them anyway. You'll notice though that only one iono file will be saved no matter how many receivers you download from.

J.D.

just guessing again

What I saw the guys doing was to set the thing up to do real time DGPS using L1. They took some wire and some 9 pin connectors and made the thing do what somebody claimed no Ashtech receivers would do. I do not know why he said that no Ashtech receivers would do real time DGPS when the only thing he had tried to do it with was a ProMark2 but the point was that if you want to turn surveying and navigation into a science project there is an opportunity to do so.

If the ProMark2 has a way to even listen to the L2 I don't know about it. It's a small box for a low price. Nobody intended it for dual frequency work.

The question, often presented as a challenge, is whether it will do this or that. Last week somebody told me he wanted to do COGO in the ProMark2. Please ponder for a little bit on what you spent for your data collector and some of the other things with lots of bells and whistles.

You can buy a system from Ashtech that will do more things than you can do with a ProMark2. It's just a matter of money.