Just for kicks, I used the Canadian PPP service to process some static data that I had previously processed through OPUS. Is it just me, or is there no place to enter the ARP height?
I believe they read this from the header of the RINEX file.
From the RINEX specifications here:
ANTENNA: DELTA H/E/N
- Antenna height: Height of bottom surface of antenna above marker
- Eccentricities of antenna center relative to marker to the east and north (all units in meters)
In the NRCAN PPP solution results file they include:
APC to ARP: antenna phase center to Antenna reference point which I believe is obtained from the IGS antenna calibration files.
ARP to marker: antenna reference point to marker which is read from the RINEX header.
> Just for kicks, I used the Canadian PPP service to process some static data that I had previously processed through OPUS.
I did just that myself, yesterday. The horizontal position agreed with OPUS to about 0.02'. The ellipsoid height differed by 0.4'
>Is it just me, or is there no place to enter the ARP height?
The measure up data is in the RINEX file, near the top.
> > Just for kicks, I used the Canadian PPP service to process some static data that I had previously processed through OPUS.
> I did just that myself, yesterday. The horizontal position agreed with OPUS to about 0.02'. The ellipsoid height differed by 0.4'
>
> >Is it just me, or is there no place to enter the ARP height?
> The measure up data is in the RINEX file, near the top.
It's not in the RINEX file unless you purposely place it there. If that's their procedure, then maybe I need to read their FAQ. Otherwise, unlike OPUS, they do not ask for your ARP height at time of submittal.
It is in the rinex file (0.000 if you don't put it in).
I have always felt that OPUS should read the height and the antenna type from the rinex file, or at least have the option to do that. I always make sure the ARP height and antenna type in the rinex file are correct.
> It is in the rinex file (0.000 if you don't put it in).
>
> I have always felt that OPUS should read the height and the antenna type from the rinex file, or at least have the option to do that. I always make sure the ARP height and antenna type in the rinex file are correct.
I guess I was used to OPUS asking for the ARP directly. Thanks everyone.
Canadian PPP service (John)
> It is in the rinex file (0.000 if you don't put it in).
>
> I have always felt that OPUS should read the height and the antenna type from the rinex file, or at least have the option to do that. I always make sure the ARP height and antenna type in the rinex file are correct.
That's great if you use a DC to crank the base up, but what happens if you use the power up mode? Then you need the blank spot that OPUS has to enter the ARP, right?
For pure static, you would be off by the ARP with the Ortho's wouldn't you?
Aloha,
I have found that many folks never check their RINEX file headers. I guess they found the conversion to RINEX challenging enough. Many of the converted files I've seen were wrong for antenna heights and while easily corrected weren't.
NGS, perhaps imagining a future where all additions to the NSRS are done by OPUS and it's variants, wants to eliminate bad solutions with the minimal effort if requiring the entry of antenna model and antenna height.
I like many of the other tools. I think the NASA tool is pretty slick. Automated processing requires that input is correct. Assuming it is doesn't make it so.
Aloha,
DMM
Canadian PPP service (John)
> > It is in the rinex file (0.000 if you don't put it in).
> >
> > I have always felt that OPUS should read the height and the antenna type from the rinex file, or at least have the option to do that. I always make sure the ARP height and antenna type in the rinex file are correct.
>
> That's great if you use a DC to crank the base up, but what happens if you use the power up mode? Then you need the blank spot that OPUS has to enter the ARP, right?
>
> For pure static, you would be off by the ARP with the Ortho's wouldn't you?
That's what I'm trying to say Kris.
Canadian PPP service (John)
Couldn't this be resolved by just opening the RINEX file in a text editor and adding the antenna H/N/E line? And that way you would also have a record of the antenna height associated with that RINEX file.
Canadian PPP service (John)
> Couldn't this be resolved by just opening the RINEX file in a text editor and adding the antenna H/N/E line?
Evidently the Canadians consider that a valid option.
Yes, of course it can be added by a text editor. I like to have all my files correct when I archive them, never know what will happen to the paper log sheet. So I make sure they are correct (HI, ant type, point name)
Like I said, I don't think OPUS should default to what is in the rinex header, but rather should give that as an option. i don't remember which service, but I remember that one of them reads the rinex, then displays what is in there and asks for confirmation.
> by trah, Wednesday, October 16, 2013, 10:08 (49 minutes ago) @ Glenn Breysacher
Couldn't this be resolved by just opening the RINEX file in a text editor and adding the antenna H/N/E line? And that way you would also have a record of the antenna height associated with that RINEX file.
>
We fill out a separate data sheet for each point with a sketch of the point and all pertinent info including the ARP height.
Sure it's easy to edit the RINEX file, but we've just never done that since we make a separate data sheet to record all the info on (and keep in the same folder as the RAW gps file, OPUS report, etc.) and OPUS always asks for it. Even if I decimate or cut out part of the observation data, I don't put it in there.
We do a lot of static surveys. We don't use data collectors for static (only for RTK), so a log sheet is a critical component. Once the data is downloaded, I run a program to input station name (always unique), antenna type, and ARP height into the trimble .dat file. That file is then what is used for processing and archiving. The rinex file is created from the dat file using teqc if needed, and therefore has the correct info in the header.
I am working on an android app so that this will be more automated. It won't communicate directly with the receiver in the field, but in the office it will enable the automatic updating of the dat file, as well as take the place of the paper log sheet.