Precise Orbit Availability Delay

The rapid orbits and available. There is no difference between the quality of these and the final products for basically all purposes.

See accuracy part of the table:
IGS Products Table

Precise Orbit: Have Not Considered One In Years

The field position is fixed by a suitable array of control points such that I have no worry, as the 0.001m possible changes are well below my error budget and the precise orbits are almost always outside my completion required date.

Establishing the continuing positions of the CNSS control points is their major use and I don't do that.

Orbits require data from all over the world including Russia. Maybe a letter of complaint from you to Putin might speed things up.

Paul in PA

Precise Orbit: Have Not Considered One In Years

> Orbits require data from all over the world including Russia. Maybe a letter of complaint from you to Putin might speed things up.

This is probably just a joke, but just to be clear: a) stations in Russia are still sending GPS/GLONASS data to IGS analysis center; b) even if they were not, there are enough stations around Russia to not affect accuracy, at least for all regular folks.

IGS Precise Orbit Is Not A Regular Task

Which is why Russia wanted to put precise GLONASS stations in the US.

True precision requires using the military component. GPS has some algorithms to get around that, but GLONASS is a somewhat different signal, since each satellite is at a slightly different frequency.

Also Russia is far greater in area than the US plus it abuts another observation station gap known as China.

Paul in PA

It does say 12-18 days. Looks like it'll be the full 18 days this time.

> The rapid orbits and available. There is no difference between the quality of these and the final products for basically all purposes.

It's a contractual requirement, so "basically all" doesn't cover it in this case.

I am not going to be like Paul and belittle the use of precise ephemerides. I always use the precise for final processing, but usually the rapid version suffices. I have noticed hardly any difference at all between the two (final and rapid).

I Have Not Belittled Precise Orbits

I merely state that I find no need for them in my work.

If that is what I get then I use it, but I do not go out of my way, nor do I obligate myself to wait for someone else to provide them.

If Jim has a contractual obligation then the contract cannot be fulfilled until they are available.

But "typical delay" is a hard thing to put into an agreement.

Paul in PA

A little off topic, BUT has anyone found a source for rapid GLONASS orbits? IGS does not provide anything other than final and I think all other sources are just a single center's values and not a composite??

I had an issue recently with PP GPS/GLONASS data while attempting to use some orbits obtained from Natural Resources Canada where you can get earlier GLONASS orbits than final. I have two software packages for post processing, one of them wouldn't read those orbits. It seems that the IGS version always work, just wished they made a combined SP3 file with both GPS and GLONASS along with having a rapid GLONASS orbit available.

SHG

1792 is available now.

Precise orbits are released on Thursday, a weeks worth at a time.

Usually, But Not Last Week

Paul in PA

Usually, But Not Last Week

See: http://igscb.jpl.nasa.gov/components/prods_cb.html for GPS ephemeris availablity.

The final or precise orbits are released on Thursday for the GPS week that ended about 12 days before.

Usually, But Not Last Week

> The final or precise orbits are released on Thursday for the GPS week that ended about 12 days before.

Except when they're not, as was the case with Week 1792.

Is this still the best place to check for availability? Does NGS OPUS update at the same time this one does?
https://igscb.jpl.nasa.gov/components/prods_cb.html

I submitted an OPUS session from week 1890 today, Friday afternoon CDT, 18 days later, and still get Rapid, so I looked up this link and sure enough it says that's the best they have. Can I expect OPUS to use precise/final as soon as the linked site says it is available?

just curious how many of you use precise ephemeris and what do you use it for?

hpalmer, post: 367552, member: 336 wrote: just curious how many of you use precise ephemeris and what do you use it for?

The use of precise ephemerides is required for vector processing when compliance with NGS height modernization guidelines as they currently exist (NOS NGS-58 and NGS-59) is required. Height mod projects are they only ones for which I routinely wait for precise orbit availability, and even for those projects I'll use the rapid orbits for interim data quality checking. On other projects I'll use the precise orbits if convenient, e.g. if final processing has been delayed for some reason and the precise is available.

Jim Frame, post: 367559, member: 10 wrote: I'll use the rapid orbits for interim data quality checking.

So when you finally got your precise data this time was there any difference? I am wondering if the reason for the delay was some sort of problem with the data that needed correcting. Either that or the guy who signs off on it was on vacation last week.

Those interested in the minutiae of orbit calculation, combination, QC and dissemination can monitor the process via IGSMail. Some examples of what's available are shown below:

On the issue of differences in orbit products, see the latest IGS comparison: https://igscb.jpl.nasa.gov/pipermail/igsreport/2016-April/024369.html

This is a comparison of Ultra Rapid (predicted) and Rapid.

This link describes some of the details about combining orbit products from various analysis centers: https://igscb.jpl.nasa.gov/pipermail/igsreport/2016-April/024398.html

Also note that the NGS role as IGS Analysis Center Coordinator ended with a transition to GA and MIT as described below:

"On Thursday January 14, 2016, the role and operational data processing for the IGS Analysis Center Coordinator (ACC) will transition from NOAA/NGS to a combined role for Geosciences Australia (GA) and MIT. The operational data processing to generate the IGS ultrarapid, rapid, and final orbit and clock products will be carried in a cloud computing environment sponsored by GA. The operational oversight of product quality and generation will be split between GA and MIT depending on time day. The new system has been running in parallel for the past two months and has been generating results that are fully consistent with the NOAA/NGS operational processing.
For users and analysis centers, there should be no apparent changes after the transition. All the products are available from and deposited to the same locations as currently. While it is expected that the transition should happen transparently, there could be some delays as the new team works through any problems that do arise. Kevin Choi at NOAA/NGS has graciously agreed to continue his assistance during the transition and the new team is very thankful for this."

DMM