Bad GPS Afternoon? G4 Solar Storm 3:00 pm EDT 22 June 2015

Howdy Mark,

My Javad LS, using a Triumph2 base has been running non stop since 3pm today until now (midnight) doing some tests of a development version. I was unaware of the space weather event.

The Javad gear has been clicking right along, and is completely unaffected.

Mark: Thanks for the update

Man, that Kp index is up there!

The last solar storm I worked in seemed to affect long range RTK, but didn't seem to affect short base rover vectors perceptibly. I can't speak to this one. Like John, last night I started a test at about 300 utc. But my test is under canopy with a 200' baseline. It'll be hard to tell what affect the storm is having on it. Also since it was overnight the ionosphere would have calmed somewhat.

John Evers, post: 323867, member: 467 wrote: Howdy Mark,

My Javad LS, using a Triumph2 base has been running non stop since 3pm today until now (midnight) doing some tests of a development version. I was unaware of the space weather event.

The Javad gear has been clicking right along, and is completely unaffected.

I located several points with the Triumph 2 during a solar storm a couple months ago (didn't know until after trying to process). 20-30 minute occupations for rapid static submittal. Only one gave a solution (not a good one) through OPUS, none gave a solution through DPOS. Had a similar result last fall with the LS; last pipe located did not check with total station location, turned out a solar storm had started just before I occupied that point. Longer occupation time may be the answer for the base, but I would think it would still affect the rover shots. Let us know how it turns out.

John Evers, Would you go and look and see if you just happen to have an extra LS under your bed, or in the closet? I think I need one!

We switched to redundant RTK for the last half of the day. If things got squirrely we would catch it. When the job site is 300 miles away you either do good checks or lose your behind. .

thebionicman, post: 323897, member: 8136 wrote: We switched to redundant RTK for the last half of the day. If things got squirrely we would catch it. When the job site is 300 miles away you either do good checks or lose your behind. .

Did you see any adverse affects to your RTK positions during the high Kp?

I'm going to give Mark Silver some love.

This is a GPS salesman that actually accurately warned of solar storm interference. I've heard of untold numbers of GPS salesmen who, at the hint of any difficult to diagnose issue with GPS, often caused by communication issues, ephemeris issues, etc., immediately bring in to question the influence of solar storms or sun spots. This happened a lot during the GLONASS outage a year ago. "RTK not working? Must be sunspots." Apparently no one bothered to look at the http://www.swpc.noaa.gov/ to see if that was actually true. Much easier to attribute negative influence from invisible x-ray storms to your magical black box.

I recall during the solar maximum of ~2000 the difficulty in performing static observations with L1 only GPS equipment. The struggle was real, let me tell you. Space Environment Center and Space Weather were two very frequently visited websites for us. There were days that results would be extremely noisy and other days where results were simply not obtainable. Eventually the solar max waned and there was no longer a need for paying attention to the uneventful Sol. Fast forward a decade and a half, in March of 2015, we experienced a pretty significant solar event. RTK at eight miles suddenly quit working in the afternoon after a successful morning at those ranges. Upon receiving texts from friends across the country experiencing the same issues, a quick check of the space weather showed a high Kp index. Back at the office, a hundred feet from the base, the rover fixed as normal and RMS values appeared to be normal as well. I don't know what the effect on modern equipment is entirely. We knew back in 2000 what to expect with our equipment at the time because we had a lot of experience during that double hump solar maximum. Limited experience today suggests that long range (a subjective term) vectors will suffer, short ones will not. This makes some sense to me as the variations in the atmosphere during a solar storm will likely be substantial on points separated very far apart, whereas normally the atmosphere over points a few miles apart is more homogenous.

Back to Mark, he's a hell of a student of GPS, and the fact that he's a GPS salesman who only brings up space weather when there is actually space weather occurring is another reason I appreciate his presence in our field.

I'd be interested to know from our resident RTN experts what they've observed with modern equipment in these past few events.

Mark, I posted this pretty image in my parallel thread I started yesterday, I am real curious to know if there were actual problems, when it hits red, I have always shut down. Fortunately I suppose depending on how you look at it, the ground weather was too cloudy to fly yesterday, so our photo plane didn't acquire any data for me to try and post process.

SHG

My e-mail has been blowing up with alerts for the past couple days, if anyone had issues yesterday, the event isn't over yet and you might want to consider avoiding a repeat, of course if it didn't effect you yesterday, carry on.

SHG

Shawn Billings, post: 323903, member: 6521 wrote: I'm going to give Mark Silver some love.

This is a GPS salesman that actually accurately warned of solar storm interference. I've heard of untold numbers of GPS salesmen who, at the hint of any difficult to diagnose issue with GPS, often caused by communication issues, ephemeris issues, etc., immediately bring in to question the influence of solar storms or sun spots. This happened a lot during the GLONASS outage a year ago. "RTK not working? Must be sunspots." Apparently no one bothered to look at the http://www.swpc.noaa.gov/ to see if that was actually true. Much easier to attribute negative influence from invisible x-ray storms to your magical black box.

I recall during the solar maximum of ~2000 the difficulty in performing static observations with L1 only GPS equipment. The struggle was real, let me tell you. Space Environment Center and Space Weather were two very frequently visited websites for us. There were days that results would be extremely noisy and other days where results were simply not obtainable. Eventually the solar max waned and there was no longer a need for paying attention to the uneventful Sol. Fast forward a decade and a half, in March of 2015, we experienced a pretty significant solar event. RTK at eight miles suddenly quit working in the afternoon after a successful morning at those ranges. Upon receiving texts from friends across the country experiencing the same issues, a quick check of the space weather showed a high Kp index. Back at the office, a hundred feet from the base, the rover fixed as normal and RMS values appeared to be normal as well. I don't know what the effect on modern equipment is entirely. We knew back in 2000 what to expect with our equipment at the time because we had a lot of experience during that double hump solar maximum. Limited experience today suggests that long range (a subjective term) vectors will suffer, short ones will not. This makes some sense to me as the variations in the atmosphere during a solar storm will likely be substantial on points separated very far apart, whereas normally the atmosphere over points a few miles apart is more homogenous.

Back to Mark, he's a hell of a student of GPS, and the fact that he's a GPS salesman who only brings up space weather when there is actually space weather occurring is another reason I appreciate his presence in our field.

I'd be interested to know from our resident RTN experts what they've observed with modern equipment in these past few events.

During the same solar event I mentioned above, I tried the LS via RTN. It showed the interference and would not get a fix, at least not for the 10 minutes or so I attempted. There was still some interference the next day (moderate kp) and it did get fixed solutions that subsequently verified (sorry, not with least squares). Our RTN in that area was sending corrections for Glonass and GPS. About 20km to the nearest cors.

It is not just solar storms that affect GPS, even on normal day the sun can interfere.

I can remember years ago at NJIT I was analyzing n occupation, that just did not want to resolve to a tight solution. Using SKI I looked at pages and pages of residuals. One particular satellite jumped off the page, so I investigated further, this was an afternoon observation and this particularly satellite was in the southwest, such that it was backdropped by good ole Sol. I only removed the few minutes of this satellite during the bad residuals and had an extremely good solution. Consider laser light which is very strong because of all the matching wavelengths. Now we have a weak GPS signal riding parallel to a similar frequency from the sun.

I would hesitate before trying to edit observations on a bad sun day, when the sun is jumbling up extreme ionospheric variances..

Paul in PA

Well, from a salesman's perspective (I am actually an Electrical Engineer too, in my defense):

The L1 only systems (ProMark 2 and ProMark 3) with baselines greater than 5 KM can get screwy. L2 and multi-constellation if they are already turned on and tracking SV's will be okay (assuming baselines less than 10 miles or so.) RTK network solutions are great during storms. I have never seen noticeably difficult times.

However, my experience is that if you pull a receiver out of a drawer (or in my case a box) that has been turned off for a month or so and try to initialize during the G4+ events, they will track 2 or 3 SV's for a while and just not figure out where they are on the earth. I turn them off, do a reset and just can't get them to track (Z-Max receivers are notorious for this in my opinion.) Then I get sidetracked and when I come back they are tracking a full host of SV's and all is well, I am left thinking that I did something to make them work. But I don't know what it is that I might have done.

Of course, I never think to check SWPC for the current status.

Yesterday at about 2:50 pm (EDT) I got three calls from customers who said that their receivers would not track any SV's. One customer had a NovAtel engine, a Trimble engine and an Ashtech engine all failing within 5 feet of each other. My first thought was 'Jammer' but, later when they all started tracking together I took a look at SWPC and figured it might be that.

But I don't know for sure.

My real concern is the leap second next Wednesday morning (July 1). Wouldn't it be funny if all of the GPS receivers that I have ever sold won't track SV's starting July 1st? (Okay, not funny at all.)

🙂

Mark

I operate a 50+ station network and did notice a big Issue yesterday.

However, i believe it had more to do with the HORRIBLE Satellite availability.

(Chicago)