What is considered long static.
I was reading specs and it states
Static. 5mm
Long Static 3mm
How long do you have to observe for long static?
Depends on distance. I would guess more than 4 hours to be long static, but even then that is not long enough for some expectations.
There is no definite cutoff time, but "long" static would be a bare minimum of 30 minutes in my mind, usually over an hour and up to several hours.
BTW, the usual nomenclature is Rapid Static (or Fast Static), for short duration occupations / short baselines & Static for long baselines / long durations. Typical cutoff for long/short baselines is 20 kms.
A good question that doesn't have a finite answer (IMO).
Vector Length
PDOP,HDOP,VDOP,GDOP,TDOP
Multipath conditions (BOTH ends of the vector)
Troposphere
Magnetosphere
Ionosphere
so forth and so on...
ALL factor into this.
Under IDEAL conditions, I believe that "IT (still) DEPENDS...
Primarily on vector length, but even that isn't set in stone.
Bottom Line...Redundancy, Redundancy, REDUNDANCY
Loyal
Depends on what you do with the static.
Do it yourself, totally varies.
To get the best expectation from OPUS, two 5 hour observations under different constellations. An OPUS observation involves 3 CORS and can be solved against more groups of 3.
In some areas the same results might be achieved with fewer hours of observations, broken into short segments and sent to OPUS-RS. An OPUS-RS observation uses up to 9 CORS at once and CORS are so prevalent in some areas that one can resubmit and specify a solution using 9 more different CORS. In addition OPUS-RS uses more observables than L1 & L2 to get a solution.
I try to do all my work with OPUS-RS but sometimes have to rely on OPUS solutions.
Paul in PA
I run a lot of 24 hour observations. The OPUS results on one point I have hammered with 24 hour observations have a range of 3 mm horizontal and about 10 mm vertical. The Standard Deviations are very low because I have a LOT of observations. These observations are all with an OPUS X90 I am going to swap out the receiver on Wednesday and will have a few more sessions to submit. OPUS may be slow in about 2 weeks. I want to get the precise ephemerious for all the sessions.
Loyal, post: 333313, member: 228 wrote: A good question that doesn't have a finite answer (IMO).
Vector Length
PDOP,HDOP,VDOP,GDOP,TDOP
Multipath conditions (BOTH ends of the vector)
Troposphere
Magnetosphere
Ionosphere
so forth and so on...
ALL factor into this.Under IDEAL conditions, I believe that "IT (still) DEPENDS...
Primarily on vector length, but even that isn't set in stone.
Bottom Line...Redundancy, Redundancy, REDUNDANCY
Loyal
[sarcasm]Loyal, you couldn't be MORE incorrect..... the key to success is ensuring you have a pre-approved plan and that you turn in -( wait for it) rubbing with your documentation......[/sarcasm]... can you tell it's been a long couple of months......
Typically observed with Dual Frequency L1/L2 GPS/Glonass receivers.Using your own GNSS Post-Processing software package from GNSS manufacturer.
"Old school" Static observations were typically 1-hour durations, minimum 5 SV's, PDOP < than 006.
Rapid Static observations "Rule of Thumb", 5-minute observation, plus 1-minute additional observation time for every Km separation between points, (Vector/Baseline length). 5 SV minimum, PDOP < than 006. (Longer baselines = longer observation times).
Long Static observations, typically 5.5 hour durations, 5 SV minimum, PDOP < 006
Specs may also require 100 % Double Baseline observations with different SV constellation, (different time of day). Long Static may also include use of precise ephermeris for Post-Processing.
Concur with Paul's recommendations for OPUS-RS and OPUS-Static
One of the trade pubs ran a great article about 12 years ago that hypothesized that the practical limiting factor on baseline length is the duration of the observation (if anyone knows where to find that it would be greatly appreciated). When the terms "Rapid" and "Fast" static first came into use they connoted 20 minutes or less with dual frequency receivers; prior to that a static session was one to two hours or more. I would consider a "long" static session to be over about four hours but honestly I've never really heard that term used.
Would you guys who use OPUS a lot prefer to submit a 24 hour session as one single file or would you break it into 6 or 8 hour sessions? I'm about to survey in a CORS station and I'm pondering the relative merits of different post processing methods and session times.
John Giles, post: 333309, member: 57 wrote: What is considered long static.
I was reading specs and it states
Static. 5mm
Long Static 3mm
How long do you have to observe for long static?
It's all static, PPK, fast static, static, long static, short static, there really isn't a magic time or process that will define the accuracy, the files will look the same. The accuracy is dependent on redundancy.
I respectfully beg to differ - redundancy is obviously important but observation time is the primary factor in the precision of a single baseline.
http://www.novatel.com/assets/Documents/Waypoint/Reports/Static_Accuracies.pdf
The results of these tests clearly demonstrate that the accuracy of baselines of any length continue to improve out to about the six hour mark, beyond which only very long baselines continue to improve significantly.
The guidelines I work under at
Up to 10 KM, 10 minutes regardless
Past 10 KM, 1 minute/klick, or distances in kilometers = time in minutes.
Anything past that is "long" for me.
I suspect that it is some reference to multiple constellations and helping to resolve different models.
Lee D, post: 333340, member: 7971 wrote: One of the trade pubs ran a great article about 12 years ago that hypothesized that the practical limiting factor on baseline length is the duration of the observation
This is an interesting question. I'd guess that it's actually a function of the number of epochs (observation duration) with some minimum number of co-visible satellites.
I typically collect a "Long Static" on the base by default and then if I want double checks on the rover I will collect static data and process RS through NOAA. Results have been varied but typically good.
As far as Long Static, I try to get at least 2 hours. That seems to be the 'sweet spot' for accuracy versus time spent. Results are really good and I feel comfortable basing most of my projects on a solid static point. It has worked well so far. Did quite a bit of OPUS-DB points many years ago and that was at least 4 hours of good data. Excellent results as it turns out. Typically well within the 3mm range.
I've found that with OPUS anything over four hours on an unobstructed point is generally pretty tight. We did a big network in OPUS-Projects recently that had for the most part three hour sessions, and that came out good. Some of the individual solutions didn't meet the specs but once you run the session adjustment everything tightens right up.
Similar to some of the above, but for "fast" static I do 15 minutes on all points for baselines up to 15 km, then 1 minute per km above 15.
I consider static to be a minimum of 30 minutes. One thing to understand, that some people do not...the data is the same regardless of whether you call it static or fast static or rapid static or whatever. A lot of projects we setup one receiver and let it collect the whole time we are there, could be 4 to 8 or even more hours, on multiple days. The other receivers may float around, short or long, but at least one receiver is running long for a good tie to CORS.
John Hamilton, post: 334525, member: 640 wrote: Similar to some of the above, but for "fast" static I do 15 minutes on all points for baselines up to 15 km, then 1 minute per km above 15.
I consider static to be a minimum of 30 minutes. One thing to understand, that some people do not...the data is the same regardless of whether you call it static or fast static or rapid static or whatever. A lot of projects we setup one receiver and let it collect the whole time we are there, could be 4 to 8 or even more hours, on multiple days. The other receivers may float around, short or long, but at least one receiver is running long for a good tie to CORS.
It can be a bit frustrating, trying to explain that if you start a session in your PPK style or your RTK/INFILL style that it's the exact same data you get with STATIC or FAST STATIC.
Of course you may have different recievers and logging devices but at the end of the day it's the same data, you can use it the same way.
