ecanderson

Yes, that deals with cases where you can see the green, blue and purple signals, but what happens when you're in a situation (and I'd argue that their picture shows EXACTLY this problem if you think that green signal is going through a steel and reinforced concrete building - not) where the original green signal is obscured. The green signal isn't going to pass through a skyscraper. In a true 'urban canyon', or even a real one, there are usually more reflected signals than there are direct ones since the 'slot' through which there is line-of-sight to satellites is quite narrow, running along whatever axis the street runs, and only a small number of degrees wide - and runs narrower with taller buildings. The vast majority of the constellation is obscured from direct line-of-sight reception, and only their reflections are available. THAT'S where it gets really messy, and is where the L1/L2 differential that normally could assist simply cannot. I don't see how the addition of L5 changes that. Seems to me that there's no simple solution to that. That leaves us with a narrow corridor in the sky with available direct signals, which, no matter how many in the constellation happen to fall within that axis, is NOT an optimal geometry to work with for positioning accuracy.

@Mineral2 Or worse, you don't even get two versions (direct and delayed) of the signal, but instead, you get one delayed signal off the side of a building or canyon face (or the whatever) while the original signal is obscured (no direct line of sight to the satellite). When in narrow confines with few satellites to work with, it can most definitely throw things off a good bit. It's one of the reasons that 'urban canyon' caching can be such a PITA. As to the earlier comments about frequency (band) vs. propagation speed, Capt. Bob has that right on the money. That's nice for dealing with ionospheric delays which we used to depend upon WAAS and EGNOS to deal with. Truth is, the newer birds (IIR and later) are all sending on L1/L1C (1575.42 MHz) and L2/L2C (1227.6 MHz) bands, and that's where the differential time to arrive is presently being computed to deal with the atmospherics. That was already enough frequency spread to do the computation. The fact that L5 is just a little lower yet (1176.45 MHz) isn't necessary to that job. None of which addresses the multipath issue, or how the addition of L5 is expected to help in that regard. The frequency difference between the two signals from the same bird won't have any significant impact on the time of arrival on the two reflected signals in the relatively tiny distance between you and that building over there. If it were that easy, the L1/L2 difference would already be making that solution possible. Still searching for clues here.

My Samsung S20 has been indicating the presence of L5 signals, too, but don't know if the health status issue was still a factor in whether they were being used for position calculation. Your chart only indicates that the 2F and 3 satellites are in operation, and they are all 'multi-banders', so will look like that whether L5 is actually functional yet or not. It doesn't say specifically what the L5 messaging is at present. Haven't seen a peep out of the govt as to the current L5 status in a while. It had been 'Pre-operational' for eons. Search didn't turn up any new information, either. Even the govt page still shows 'Pre-operational' and "Unhealthy", but the page hasn't been updated since August 2020. https://www.gps.gov/systems/gps/modernization/civilsignals/

Reminds me ... Have any of the 16 or so L5 capable systems started reporting anything but "Unhealthy" yet?

Wrong scenario. It's when only the reflected signal is available at decent S/N that things start to go south. We're not talking about differentiation of the same signal with different time domains (and of course, that happens, too), we're talking about situations where the receiver is seeing only reflected signals in the wrong time domain because the line of sight signal is obscured. Receiver doesn't know that the signal it is receiving is the reflected (delayed) version. Common in urban canyons. It's still more than I can quite follow as to how L5 is expected to mitigate these issues, but that's the word going around.

" Is there a GSAK type app available? " For what? Your phone? GDAK was once available, but I don't know if had anywhere near the slice and dice ability of GSAK.

Indeed. Irrespective of the future enhancements to the system in the sky, current models aren't seeing numbers resolved to 0.0001 provide any benefit to the person staring at the screen. I just call it wishful thinking.

We've been talking about L5 here in the forum for a while, and are looking forward to GPSIII satellites in the future as well. L5 should help to resolve some of the issues that degrade positioning performance. GPSIII will mean that we no longer need to depend upon ground based references like WAAS and EGNOS, which will be nice as well. And more birds in the sky has already improved ephemeris issues and the occasional lousy HDOP that we used to encounter for a couple of hours on particular days when the constellation was a bit whacked relative to our ground position. But there will still be challenges to getting the level of precision described in that talk in anything but ideal conditions. Multipath issues, which I think will likely be improved by L5, will always remain a bugaboo that has to be dealt with in software to some lesser or greater benefit. Quickly sorting whether a signal is direct or reflected is certainly something that continues to perplex some GPSr manufacturers now. S/N ratios will remain an ongoing technical challenge as well. Again, not an issue under ideal open sky conditions, but we don't always cache in an ideal environment. Heck, I don't even know if Garmin's clocks (or any others in consumer goods) are tight enough to resolve the levels that this guy is talking about (0.63m?) Would be interesting to know whether the GPSr chip manufacturers are going to have to improve their own specs to take advantage of this, and how difficult or costly it might be. They may be there now, or it could pose a hurdle. No way to know from where most of us sit. As an aside: Good on them for finally preparing to dump NAD83 in favor of a more realistic model. Long overdue.

No, and for this technology, anything past the third decimal place in minutes is just silly. Makes about as much sense as dd.dddddd 1 minute of latitude is about 6068 feet. So... 0.001 minutes of latitude (N/S) equates to about 6 feet. You'd be lucky to get that kind of EPE on a good day. But 0.0001? 1/10 of 6 feet? 7 inches? Caching wouldn't be very challenging if we were there. 0.0001 minutes of longitude (E/W) is just as silly as using it for latitude at the equator, and gets even sillier as you go north or south from there since each 0.0001 gets smaller and smaller.

Walking a county road easement where there are no paved alternatives isn't a violation of anything in this part of the world. It's a fact of life. Neither is parking on one unless prohibited by signage, which does occur in rare instances. We've certainly never been hassled about it, and it occurs fairly frequently -- usually several times on each cache run. Many of our COs are good enough to place them where there's a wide pull-out, which is a bonus, but is never assured. If we are ever ticketed for parking improperly (which has never happened) in such kinds of places, we'd just pay the ticket if it was legit. Honestly, I'd worry more about people who park for a GR cache and aren't clear of the through lane. Dangerous for both the cacher and any other traffic. That really would be worth a ticket. Commercial property can be an issue no matter how one presents. We want to cache, not get caught up in conversations or conflicts, which did occasionally occur when caching as 'civilians'. We don't want to have to deal with asking every CO if they've received permission, and who gave it to them (that's the reviewer's job) nor in the event that permission has been granted, find the right person in management to explain it to the local mall cop. Avoiding all of those kinds of issues was 99% of the point of our current method, and it has proven even more successful than we originally imagined. Five years with this method, thousands of caches, and NO negative contacts (not even 'mall cops' <g>) since the conversion.

I guess that's where we keep running by each other. For what reason would we be discussing this with a judge? I thought I was clear earlier about trespassing issues and how we deal with them rather specifically. We don't do the search, and we post photos of the warning indicators in NM logs. Should probably post them as NA logs, but we like to give the CO a chance to explain, if there is an explanation to be had (e.g., "It's my property"). Sometimes, it's a matter of clarifying the situation in the description, and sometimes it's just not going to work. So if we remove probable cause for trespass, what's the next option in the arsenal? Seriously, I'm trying to understand, but not getting there. Understand that the ruse is for the rubes, not LEO. With them, we play it straight if questioned, which almost never happens anyway. I'm up to my wazoo in DFARS contracts at the moment, but am not at all concerned about clearances due to our caching methods.

PM me with it, if you like. I won't be going after that specific cache in any case. A little outside of my caching territory!

Haven't run across an online tool like that. There's a standalone *.exe called CryptoCrack that does a half decent job of ranking the most likely possibilities for cypher type. What is this online tool?

Operative word was "can". It is definitely possible to design an AL either to require sequential discovery or not.

Objection. Calls for speculation by the witness. I was hoping a 'government lawyer' wouldn't make too many assumptions. We don't trespass, so that aspect of the game is a non-issue. In fact, I have numerous times seen signs that make it clear that the CO has placed a cache in an improper spot, requiring trespass to access. I take a photo of the sign and post it in my NM log. As for those two 'gates' I mentioned, they were in fact erected illegally across a county road. Locals thought it was a cute way to create their own 'gated community' by blocking access. They had used a bunch of daisy-chained locks. A certain someone in the county had turned a blind eye until we brought it to the County Commissioner's attention. Not a problem now.

Looks like you gave up and just went with straight ASCII text.

That doesn't always work. For some, the setting shows default in imperial units, but to get it to BE in imperial units, it is first necessary to switch to metric, then back to imperial units. Then it 'sticks'. It's a simple bit of miscoding. The displayed toggle default is imperial, but the code default is metric.

No, pieces of the bonus solution can be sprinkled among the five journals. Done properly, there is nothing about adding bonus cache clues that requires that the AL be sequential..

Indeed. Back in '67, the IBM 1130 I was using had only 16K of foreground memory and 16K of background memory. Then again, that's back when a FORTRAN compiler could run in 4K. APL was a total kick. Here's a "Pick 6" (from 40) lottery number generator: x[⍋x←6?40] If you didn't know the language well, it was just Hieroglyphs.

Yes, apart from the Improbability Drive, which wasn't an option offered by the dealer at the time, the cachemobile was upgraded. The vehicle now looks the part a bit more than it did before. We also have 'company' jackets with the logos in two weights, chosen based upon the season. Right now, it's the fleece! We've had people volunteer to open locked gates for us, we park 'as needed', and are otherwise nearly always completely ignored. If anyone does ask, we either give them the whole geocaching story, or fall back on the old "We're confirming the location of benchmarks" line, depending upon who's asking and how much time we feel we have to chat. I can't tell you how much easier it's been since we adopted this approach.

https://www.geocaching.com/p/default.aspx?guid=445ccd85-07c9-4752-aaee-829d2c4168bc

Wireless doesn't seem that awkward to me - once you have the phone and device registered and paired up. You place the requisite app (Garmin Connect) on your phone, and pair it up to your Oregon 700. Once that initial setup is done... If you want 'current' data on any cache, it's just a matter of hitting search (for a geocache) and the button that makes the wireless request back to gc.com through your phone.

If I could just get a workable Improbability Drive for the cachemobile. So far, I've only found them in Extra Large.

Fragen Sie weiterhin Ihren Prüfer. Die Antwort muss von ihm kommen.

I definitely agree. Observing how other owners hide their thingies can be very instructive. There may be local and State laws prohibiting this, of course.