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Groups > comp.sys.mac.system > #98377 > unrolled thread
| Started by | David Ryeburn <david_ryeburn@telus.netz> |
|---|---|
| First post | 2017-01-07 17:23 -0800 |
| Last post | 2017-01-14 23:03 -0500 |
| Articles | 20 on this page of 102 — 19 participants |
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Re: Merry Christmas! David Ryeburn <david_ryeburn@telus.netz> - 2017-01-07 17:23 -0800
Re: Merry Christmas! dorayme <do_ray_me@bigpond.com> - 2017-01-08 14:03 +1100
Re: Merry Christmas! JF Mezei <jfmezei.spamnot@vaxination.ca> - 2017-01-08 13:35 -0500
Re: Merry Christmas! "Rod Speed" <rod.speed.aaa@gmail.com> - 2017-01-09 05:42 +1100
Re: Merry Christmas! Lewis <g.kreme@gmail.com.dontsendmecopies> - 2017-01-08 20:01 +0000
Re: Merry Christmas! Tim Streater <timstreater@greenbee.net> - 2017-01-08 22:48 +0000
Re: Merry Christmas! Lewis <g.kreme@gmail.com.dontsendmecopies> - 2017-01-09 02:05 +0000
Re: Merry Christmas! Alan Browne <alan.browne@freelunchvideotron.ca> - 2017-01-09 15:52 -0500
Re: Merry Christmas! John Somerset <somerset@nospam.com> - 2017-01-08 21:44 -0500
Re: Merry Christmas! "Rod Speed" <rod.speed.aaa@gmail.com> - 2017-01-09 14:27 +1100
Re: Merry Christmas! Lewis <g.kreme@gmail.com.dontsendmecopies> - 2017-01-09 12:06 +0000
Re: Merry Christmas! John Somerset <somerset@nospam.com> - 2017-01-09 19:16 -0500
Re: Merry Christmas! Your Name <YourName@YourISP.com> - 2017-01-10 13:39 +1300
Re: Merry Christmas! "Happy.Hobo" <Happy.Hobo@Spam.Invalid> - 2017-01-14 23:17 -0500
Re: Merry Christmas! Davoud <star@sky.net> - 2017-01-08 01:41 -0500
Re: Merry Christmas! Lewis <g.kreme@gmail.com.dontsendmecopies> - 2017-01-08 06:55 +0000
Re: Merry Christmas! JF Mezei <jfmezei.spamnot@vaxination.ca> - 2017-01-08 17:24 -0500
Re: Merry Christmas! John Somerset <somerset@nospam.com> - 2017-01-08 11:38 -0500
Re: Merry Christmas! Don Bruder <dakidd@sonic.net> - 2017-01-08 09:18 -0800
Re: Merry Christmas! AL <45364747@invalid.com> - 2017-01-08 11:03 -0700
Re: Merry Christmas! Lewis <g.kreme@gmail.com.dontsendmecopies> - 2017-01-08 19:35 +0000
Re: Merry Christmas! Don Bruder <dakidd@sonic.net> - 2017-01-08 14:05 -0800
Re: Merry Christmas! JF Mezei <jfmezei.spamnot@vaxination.ca> - 2017-01-08 17:56 -0500
Re: Merry Christmas! Don Bruder <dakidd@sonic.net> - 2017-01-08 15:21 -0800
Re: Merry Christmas! JF Mezei <jfmezei.spamnot@vaxination.ca> - 2017-01-08 21:15 -0500
Re: Merry Christmas! Lewis <g.kreme@gmail.com.dontsendmecopies> - 2017-01-09 02:45 +0000
Re: Merry Christmas! JF Mezei <jfmezei.spamnot@vaxination.ca> - 2017-01-08 22:18 -0500
Re: Merry Christmas! Alan Browne <alan.browne@freelunchvideotron.ca> - 2017-01-09 16:40 -0500
Re: Merry Christmas! "Happy.Hobo" <Happy.Hobo@Spam.Invalid> - 2017-01-14 23:35 -0500
Re: Merry Christmas! Alan Baker <alangbaker@telus.net> - 2017-01-14 21:56 -0800
Re: Merry Christmas! Alan Browne <alan.browne@freelunchvideotron.ca> - 2017-01-15 08:30 -0500
Re: Merry Christmas! Lewis <g.kreme@gmail.com.dontsendmecopies> - 2017-01-09 02:25 +0000
Re: Merry Christmas! JF Mezei <jfmezei.spamnot@vaxination.ca> - 2017-01-08 22:08 -0500
Re: Merry Christmas! Lewis <g.kreme@gmail.com.dontsendmecopies> - 2017-01-09 12:01 +0000
Re: Merry Christmas! JF Mezei <jfmezei.spamnot@vaxination.ca> - 2017-01-09 18:15 -0500
Re: Merry Christmas! Alan Browne <alan.browne@freelunchvideotron.ca> - 2017-01-09 20:07 -0500
Re: Merry Christmas! Lewis <g.kreme@gmail.com.dontsendmecopies> - 2017-01-10 05:26 +0000
Re: Merry Christmas! Alan Browne <alan.browne@freelunchvideotron.ca> - 2017-01-09 20:04 -0500
Re: Merry Christmas! JF Mezei <jfmezei.spamnot@vaxination.ca> - 2017-01-10 00:08 -0500
Re: Merry Christmas! Alan Browne <alan.browne@freelunchvideotron.ca> - 2017-01-10 18:44 -0500
Re: Merry Christmas! JF Mezei <jfmezei.spamnot@vaxination.ca> - 2017-01-11 17:06 -0500
Re: Merry Christmas! Alan Browne <alan.browne@freelunchvideotron.ca> - 2017-01-12 08:11 -0500
Re: Merry Christmas! Alan Browne <alan.browne@freelunchvideotron.ca> - 2017-01-12 16:02 -0500
Re: Merry Christmas! "Happy.Hobo" <Happy.Hobo@Spam.Invalid> - 2017-01-15 00:30 -0500
Re: Merry Christmas! JF Mezei <jfmezei.spamnot@vaxination.ca> - 2017-01-16 02:20 -0500
Re: Merry Christmas! Alan Browne <alan.browne@freelunchvideotron.ca> - 2017-01-16 16:34 -0500
Re: Merry Christmas! JF Mezei <jfmezei.spamnot@vaxination.ca> - 2017-01-16 18:18 -0500
Re: Merry Christmas! Don Bruder <dakidd@sonic.net> - 2017-01-16 18:16 -0800
Re: Merry Christmas! JF Mezei <jfmezei.spamnot@vaxination.ca> - 2017-01-17 00:01 -0500
Re: Merry Christmas! Alan Browne <alan.browne@freelunchvideotron.ca> - 2017-01-17 07:49 -0500
Re: Merry Christmas! Alan Browne <alan.browne@freelunchvideotron.ca> - 2017-01-17 07:44 -0500
Re: Merry Christmas! JF Mezei <jfmezei.spamnot@vaxination.ca> - 2017-01-17 15:57 -0500
Re: Merry Christmas! Alan Browne <alan.browne@freelunchvideotron.ca> - 2017-01-17 19:00 -0500
Re: Merry Christmas! JF Mezei <jfmezei.spamnot@vaxination.ca> - 2017-01-17 23:40 -0500
Re: Merry Christmas! Alan Browne <alan.browne@freelunchvideotron.ca> - 2017-01-20 16:07 -0500
Re: Merry Christmas! JF Mezei <jfmezei.spamnot@vaxination.ca> - 2017-01-20 18:39 -0500
Re: Merry Christmas! Alan Browne <alan.browne@freelunchvideotron.ca> - 2017-01-21 08:01 -0500
Re: Merry Christmas! "Rod Speed" <rod.speed.aaa@gmail.com> - 2017-01-22 08:13 +1100
Re: Merry Christmas! JF Mezei <jfmezei.spamnot@vaxination.ca> - 2017-01-21 17:40 -0500
Re: Merry Christmas! "Rod Speed" <rod.speed.aaa@gmail.com> - 2017-01-22 21:03 +1100
Re: Merry Christmas! Alan Browne <alan.browne@freelunchvideotron.ca> - 2017-01-22 08:32 -0500
Re: Merry Christmas! JF Mezei <jfmezei.spamnot@vaxination.ca> - 2017-01-22 14:32 -0500
Re: Merry Christmas! Alan Browne <alan.browne@freelunchvideotron.ca> - 2017-01-23 15:55 -0500
Re: Merry Christmas! Savageduck <savageduck1@{REMOVESPAM}me.com> - 2017-01-17 16:51 -0600
Re: Merry Christmas! Alan Browne <alan.browne@freelunchvideotron.ca> - 2017-01-17 18:57 -0500
Re: Merry Christmas! martin <martin@rakupottery.org.uk> - 2017-01-17 23:15 +0000
Re: Merry Christmas! "Happy.Hobo" <Happy.Hobo@Spam.Invalid> - 2017-01-18 20:02 +0100
Re: Merry Christmas! JF Mezei <jfmezei.spamnot@vaxination.ca> - 2017-01-18 15:29 -0500
Re: Merry Christmas! Your Name <YourName@YourISP.com> - 2017-01-20 09:28 +1300
Re: Merry Christmas! Alan Browne <alan.browne@freelunchvideotron.ca> - 2017-01-20 16:15 -0500
Re: Merry Christmas! "Happy.Hobo" <Happy.Hobo@Spam.Invalid> - 2017-01-20 19:17 +0100
Re: Merry Christmas! Alan Browne <alan.browne@freelunchvideotron.ca> - 2017-01-20 16:08 -0500
Re: Merry Christmas! "Happy.Hobo" <Happy.Hobo@Spam.Invalid> - 2017-01-21 01:39 +0100
Re: Merry Christmas! Alan Browne <alan.browne@freelunchvideotron.ca> - 2017-01-21 08:03 -0500
Re: Merry Christmas! sms <scharf.steven@geemail.com> - 2017-01-21 08:04 -0800
Re: Merry Christmas! Alan Browne <alan.browne@freelunchvideotron.ca> - 2017-01-21 13:07 -0500
Re: Merry Christmas! sms <scharf.steven@geemail.com> - 2017-01-21 11:21 -0800
Re: Merry Christmas! Alan Browne <alan.browne@freelunchvideotron.ca> - 2017-01-22 08:22 -0500
Re: Merry Christmas! nospam <nospam@nospam.invalid> - 2017-01-21 13:09 -0500
Re: Merry Christmas! "Happy.Hobo" <Happy.Hobo@Spam.Invalid> - 2017-01-27 00:12 +0100
Re: Merry Christmas! sms <scharf.steven@geemail.com> - 2017-01-26 17:21 -0800
Re: Merry Christmas! Alan Browne <alan.browne@freelunchvideotron.ca> - 2017-01-26 20:26 -0500
Re: Merry Christmas! "Happy.Hobo" <Happy.Hobo@Spam.Invalid> - 2017-01-14 23:54 -0500
Re: Merry Christmas! AL <45364747@invalid.com> - 2017-01-08 16:11 -0700
Re: Merry Christmas! Don Bruder <dakidd@sonic.net> - 2017-01-08 15:26 -0800
Re: Merry Christmas! AL <45364747@invalid.com> - 2017-01-08 23:26 -0700
Re: Merry Christmas! Lewis <g.kreme@gmail.com.dontsendmecopies> - 2017-01-09 12:10 +0000
Re: Merry Christmas! AL <4567784747@invalid.com> - 2017-01-09 08:46 -0700
Re: Merry Christmas! Your Name <YourName@YourISP.com> - 2017-01-10 08:48 +1300
Re: Merry Christmas! Lewis <g.kreme@gmail.com.dontsendmecopies> - 2017-01-09 20:22 +0000
Re: Merry Christmas! JF Mezei <jfmezei.spamnot@vaxination.ca> - 2017-01-09 18:22 -0500
Re: Merry Christmas! Your Name <YourName@YourISP.com> - 2017-01-10 13:20 +1300
Re: Merry Christmas! Lewis <g.kreme@gmail.com.dontsendmecopies> - 2017-01-10 05:33 +0000
Re: Merry Christmas! Lewis <g.kreme@gmail.com.dontsendmecopies> - 2017-01-10 05:36 +0000
Re: Merry Christmas! Lewis <g.kreme@gmail.com.dontsendmecopies> - 2017-01-09 02:33 +0000
Re: Merry Christmas! JF Mezei <jfmezei.spamnot@vaxination.ca> - 2017-01-08 14:19 -0500
Re: Merry Christmas! Lewis <g.kreme@gmail.com.dontsendmecopies> - 2017-01-08 19:36 +0000
Re: Merry Christmas! John Somerset <somerset@nospam.com> - 2017-01-08 21:18 -0500
Re: Merry Christmas! "Rod Speed" <rod.speed.aaa@gmail.com> - 2017-01-09 07:23 +1100
Re: Merry Christmas! "Happy.Hobo" <Happy.Hobo@Spam.Invalid> - 2017-01-15 00:38 -0500
Re: Merry Christmas! John Somerset <somerset@nospam.com> - 2017-01-08 22:01 -0500
Re: Merry Christmas! "Happy.Hobo" <Happy.Hobo@Spam.Invalid> - 2017-01-14 23:03 -0500
Page 3 of 6 — ← Prev page 1 2 [3] 4 5 6 Next page →
| From | JF Mezei <jfmezei.spamnot@vaxination.ca> |
|---|---|
| Date | 2017-01-11 17:06 -0500 |
| Message-ID | <5876ac67$0$34593$c3e8da3$dbd57e7@news.astraweb.com> |
| In reply to | #98525 |
On 2017-01-10 18:44, Alan Browne wrote: > Heading is where the boat is pointed. It has nothing to do with the > boat track. Newer GPS have electronic compass so heading can be obtained, but not sent out NMEA. However, with 2 GPS, one at stern, one at bow, one can obtain not only the heading, but also possibly different tracks. (bow has entered area with a side current that started to push boat sideways). With compass alone, you may see the change, but cannot determine if it is done at the bow or stern. (box moves left 1m or sterm moves right 1m). With 2 GPS you can. > In tight waters, GPS is not used to navigate. Eyeballs, depth sounder > and radar are. It is now. It may or may not have authority, but would provide valuable position of bow and sterm relative to the precise route needed. It still requires human knowledge to plan the route (and to oversee it, which is why you have pilots along St-Lawrence Seaway and major ports). For instance, to make a tight bend, where you enter the bend from and at what angle would dictate whether the ship as a whole will always be inside the "deep" portion of the canal. > GPS, again, is incapable of computing heading merely from PVT. At least > 2 GPS receivers (and antennas) are required to compute heading and both > would have to provide carrier phase measurements to the device computing > the heading. NMEA-0183 does not provide any such sentences to convey such. 2 different positions (bow and sterm) allow for heading of the ship even when ship speed is idle.
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| From | Alan Browne <alan.browne@freelunchvideotron.ca> |
|---|---|
| Date | 2017-01-12 08:11 -0500 |
| Message-ID | <AsqdnXAf67UPHerFnZ2dnUU7-a-dnZ2d@giganews.com> |
| In reply to | #98536 |
On 2017-01-11 17:06, JF Mezei wrote: > On 2017-01-10 18:44, Alan Browne wrote: > >> Heading is where the boat is pointed. It has nothing to do with the >> boat track. > > Newer GPS have electronic compass so heading can be obtained, but not > sent out NMEA. You can't seem to differentiate between what is actually done in ship navigation and your assumptions. -- "If war is God's way of teaching Americans geography, then recession is His way of teaching everyone a little economics." ..Raj Patel, The Value of Nothing.
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| From | Alan Browne <alan.browne@freelunchvideotron.ca> |
|---|---|
| Date | 2017-01-12 16:02 -0500 |
| Message-ID | <MKGdnSKAROBNc-rFnZ2dnUU7-RednZ2d@giganews.com> |
| In reply to | #98536 |
On 2017-01-11 17:06, JF Mezei wrote: > 2 different positions (bow and sterm) allow for heading of the ship even > when ship speed is idle. So does a compass. Which is why they are used for that purpose. -- "If war is God's way of teaching Americans geography, then recession is His way of teaching everyone a little economics." ..Raj Patel, The Value of Nothing.
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| From | "Happy.Hobo" <Happy.Hobo@Spam.Invalid> |
|---|---|
| Date | 2017-01-15 00:30 -0500 |
| Message-ID | <o5f1de$egu$1@gioia.aioe.org> |
| In reply to | #98515 |
On 01-10-2017 00:08, JF Mezei wrote: > Compass does not know about side currents, GPS does. And as the bow > enters and area with side current, it starts to shift before the stern. Not sure what you mean. GPS computes position, not current. GP was still in development the last time I went to sea, so I have no idea what is done now. If you have GPS receivers fore and aft of the class I was on last (432 feet apart), and if the accuracy is really a meter, then the heading could be computed within half a degree. But my experience with more than one GPS receiver trying to track my walk in a straight line makes me look drunk when I put it on a map.
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| From | JF Mezei <jfmezei.spamnot@vaxination.ca> |
|---|---|
| Date | 2017-01-16 02:20 -0500 |
| Message-ID | <587c744e$0$43837$c3e8da3$5e5e430d@news.astraweb.com> |
| In reply to | #98663 |
On 2017-01-15 00:30, Happy.Hobo wrote: > Not sure what you mean. GPS computes position, not current. Current causes position changes that are in addition to what the engines do. So a GPS can see both by noticing position changes. Same thing with aircraft. The pitots give airspeed, not ground speed and not actual direction of travel. Winds will give the airctaft different ground speed and direction than recorded by air speed measurement (pitot). In the past, IMUs (innertial) provided estimate of acceleration/position and actual speed/direction. GPS provide more accurate readings. > experience with more than one GPS receiver trying to track my walk in a > straight line makes me look drunk when I put it on a map. Before Bill CLinton lifted SA, this was the case. SInce then, the error is far more acceptable and has made possible turn by turn navigation for instance. But multipath in downtown still giving erroneous position. However, on a ship, especially with WAAS, the 2 receivers will get the exact same error on open terrain
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| From | Alan Browne <alan.browne@freelunchvideotron.ca> |
|---|---|
| Date | 2017-01-16 16:34 -0500 |
| Message-ID | <a_OdnUG56MD3oeDFnZ2dnUU7-LlQAAAA@giganews.com> |
| In reply to | #98687 |
On 2017-01-16 02:20, JF Mezei wrote: > On 2017-01-15 00:30, Happy.Hobo wrote: > >> Not sure what you mean. GPS computes position, not current. > > Current causes position changes that are in addition to what the engines > do. So a GPS can see both by noticing position changes. > > > Same thing with aircraft. The pitots give airspeed, not ground speed > and not actual direction of travel. Winds will give the airctaft > different ground speed and direction than recorded by air speed > measurement (pitot). Even if there were no wind, the airspeed obtained by the pitot is relative to a standard sea level atmosphere. So the indicated airspeed is useful for controlling the aircraft but is useless for navigation. It needs to be converted to true airspeed (using altitude and temperature) to get to TAS (I'm leaving out some niggly details). > In the past, IMUs (innertial) provided estimate of acceleration/position > and actual speed/direction. GPS provide more accurate readings. Airline primary long range navigation continues to be INS with inputs from GPS. All usually managed by the Flight management system (FMS). GPS is not limited to PVT. It also supplies the INS with range-rate data (the change in distance between the INS itself and the satellites) in order for the INS to correct various internal parameters and states. The Flight Management System selects (or the pilot) the nav source(s) according to Required Navigation Performance. Naturally GPS has a high weight as it's short and long term accuracy are very good. But when GPS fails, the INS (IMU) is still king and therefore still very present on all airliners and business jets and so on). It is also the primary source of attitude information although smaller aircraft may use a AHRS for that instead. >> experience with more than one GPS receiver trying to track my walk in a >> straight line makes me look drunk when I put it on a map. > > Before Bill CLinton lifted SA, this was the case. SInce then, the error > is far more acceptable and has made possible turn by turn navigation for > instance. But multipath in downtown still giving erroneous position. > > However, on a ship, especially with WAAS, the 2 receivers will get the > exact same error on open terrain Man, you really need to drop that. First off, ships use a gyro compass for heading. Period. Nothing else. Secondly, no they will not get the "exact same error". No two measurements of two GPS' will ever get the same error. Less so with two GPS receivers separated by distance and each having significant ship superstructure in the way of receiving the same satellites. They can't have the same error because they are not seeing the same satellite constellation. Thirdly, WAAS coverage is for North America. EGNOS for Europe. MSAS for Japan. A few other smaller regional systems (collectively SBAS). Outside those coverage areas, the corrections from those sources are of dwindling use for users within a few hundred km of the edges of the coverage region. But of course that doesn't matter one whit. Ships do not use GPS for heading determination. At all. You're inventing things to to justify some earlier nonsense. Let it go. -- "If war is God's way of teaching Americans geography, then recession is His way of teaching everyone a little economics." ..Raj Patel, The Value of Nothing.
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| From | JF Mezei <jfmezei.spamnot@vaxination.ca> |
|---|---|
| Date | 2017-01-16 18:18 -0500 |
| Message-ID | <587d54e1$0$10719$c3e8da3$5d8fb80f@news.astraweb.com> |
| In reply to | #98696 |
On 2017-01-16 16:34, Alan Browne wrote: > Even if there were no wind, the airspeed obtained by the pitot is > relative to a standard sea level atmosphere. So the indicated airspeed > is useful for controlling the aircraft but is useless for navigation. Exactly. Useless for navigation but critical to ensure aircraft stays in the air. > Airline primary long range navigation continues to be INS with inputs > from GPS. For many sections of the globe, GPS has been primary for a while. Trans Pacific is GPS and has been since FANS-1. Allowed for greater capacity and straight routes, saving lots of fuel. This allows for closer aircraft since their position is more precisely reported at regular intervals. > weight as it's short and long term accuracy are very good. But when GPS > fails, the INS (IMU) is still king and therefore still very present on > all airliners Of course. And would still be king for short haul flights. > Man, you really need to drop that. > First off, ships use a gyro compass for heading. Period. Nothing else. Funny, I had conversatiosn years ago with someone developping the GPS solution for ships on the seaway. > Thirdly, WAAS coverage is for North America. Hint: Seaway ships operate only in North America, do not go on open ocean. And on open ocean, a single GPS is more than enough because you are not concerned with cornering a sand bank or wall.
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| From | Don Bruder <dakidd@sonic.net> |
|---|---|
| Date | 2017-01-16 18:16 -0800 |
| Message-ID | <o5julf$uha$3@dont-email.me> |
| In reply to | #98702 |
In article <587d54e1$0$10719$c3e8da3$5d8fb80f@news.astraweb.com>, JF Mezei <jfmezei.spamnot@vaxination.ca> wrote: > On 2017-01-16 16:34, Alan Browne wrote: > > > Even if there were no wind, the airspeed obtained by the pitot is > > relative to a standard sea level atmosphere. So the indicated airspeed > > is useful for controlling the aircraft but is useless for navigation. > > Exactly. Useless for navigation but critical to ensure aircraft stays in > the air. > > > > Airline primary long range navigation continues to be INS with inputs > > from GPS. > > For many sections of the globe, GPS has been primary for a while. Trans > Pacific is GPS and has been since FANS-1. Allowed for greater capacity > and straight routes, saving lots of fuel. This allows for closer > aircraft since their position is more precisely reported at regular > intervals. > > > > weight as it's short and long term accuracy are very good. But when GPS > > fails, the INS (IMU) is still king and therefore still very present on > > all airliners > > Of course. And would still be king for short haul flights. > > > > Man, you really need to drop that. > > First off, ships use a gyro compass for heading. Period. Nothing else. > > Funny, I had conversatiosn years ago with someone developping the GPS > solution for ships on the seaway. > > > Thirdly, WAAS coverage is for North America. > > Hint: Seaway ships operate only in North America, do not go on open ocean. > > And on open ocean, a single GPS is more than enough because you are not > concerned with cornering a sand bank or wall. Funny... I can find you images, and even time-lapse movie footage, of salties (which, if you aren't already aware, is shorthand for ships that do indeed go on open ocean, as opposed to "lakers", which operate only on the Great Lakes) from, among other places, Norway, Spain, and Britain, steaming through the Round Island/Mackinac Island passage (near St. Ignace, Michigan) heading to and from Green Bay, Chicago, or any of the other ports on Lake Michigan. I think the most recent one of those was a week or so ago, though I'd have to check datestamps to be certain on that. Or locking through to/from Superior at Sault Ste. Marie. (although I think the locks closed for the season either last week or the week before, so any of those would be older) I can't give you pictures of this one, but I can tell you that in years gone by, I've spent more than a few days playing stevedore for trans-oceanic ships that have tied up at a facility known as the Wirt Stone Dock - a place along a certain little stream called the Saginaw River in, as Madonna once infamously described it, the "smelly little town" of Bay City, Michigan, off the Saginaw Bay in Lake Huron. Hint: Last time I looked, the only possible way for such ships to reach any of those places is by first traversing the full length of the SLS. Care to try telling us again how seaway ships don't go on open ocean? -- Brought to you by the letter K and the number .357 Security provided by Horace S. & Dan W.
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| From | JF Mezei <jfmezei.spamnot@vaxination.ca> |
|---|---|
| Date | 2017-01-17 00:01 -0500 |
| Message-ID | <587da526$0$17374$c3e8da3$dd9697d2@news.astraweb.com> |
| In reply to | #98703 |
On 2017-01-16 21:16, Don Bruder wrote: > Care to try telling us again how seaway ships don't go on open ocean? You mentioned the difference between salties and lakers. Lakers don't go to open ocean and traverse from Thunder Bay to Sept Iles. Never mentioned that GPS is a requirement for ships. Just mentioned that some ships have been equipped with them to aid navigating tight waters such as the seaway. (especually for ships that never leave the seaway).
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| From | Alan Browne <alan.browne@freelunchvideotron.ca> |
|---|---|
| Date | 2017-01-17 07:49 -0500 |
| Message-ID | <kvKdne66-e1fj-PFnZ2dnUU7-cPNnZ2d@giganews.com> |
| In reply to | #98703 |
On 2017-01-16 21:16, Don Bruder wrote: > Hint: Last time I looked, the only possible way for such ships to reach > any of those places is by first traversing the full length of the SLS. > > Care to try telling us again how seaway ships don't go on open ocean? There are "laker" ships that do indeed only ply the SLS and much of the St-Lawrence. They are not well suited for ocean work. There are also lakers that are too large to exit the system as the downstream locks at some point are too small. There are of course ocean going vessels that are small enough for the SLS as well. -- "If war is God's way of teaching Americans geography, then recession is His way of teaching everyone a little economics." ..Raj Patel, The Value of Nothing.
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| From | Alan Browne <alan.browne@freelunchvideotron.ca> |
|---|---|
| Date | 2017-01-17 07:44 -0500 |
| Message-ID | <1e2dnVTFjY0EjOPFnZ2dnUU7-dXNnZ2d@giganews.com> |
| In reply to | #98702 |
On 2017-01-16 18:18, JF Mezei wrote: > On 2017-01-16 16:34, Alan Browne wrote: > >> Even if there were no wind, the airspeed obtained by the pitot is >> relative to a standard sea level atmosphere. So the indicated airspeed >> is useful for controlling the aircraft but is useless for navigation. > > Exactly. Useless for navigation but critical to ensure aircraft stays in > the air. > > >> Airline primary long range navigation continues to be INS with inputs >> from GPS. > > For many sections of the globe, GPS has been primary for a while. Trans > Pacific is GPS and has been since FANS-1. Allowed for greater capacity > and straight routes, saving lots of fuel. This allows for closer > aircraft since their position is more precisely reported at regular > intervals. GPS does not allow for straighter routes than INS in the grand scheme of things. Direct-to NAV predates GPS by a very long time. FANS is not about GPS. It's about communication (data links) so that the positions of aircraft are accurately known in order to guarantee separation. Since GPS is not a perfectly reliable sole means navigation system, inertial in one form or another is always required. > > >> weight as it's short and long term accuracy are very good. But when GPS >> fails, the INS (IMU) is still king and therefore still very present on >> all airliners > > Of course. And would still be king for short haul flights. > > >> Man, you really need to drop that. >> First off, ships use a gyro compass for heading. Period. Nothing else. > > Funny, I had conversatiosn years ago with someone developping the GPS > solution for ships on the seaway. They were manifestly not using it to determine ship heading. Put up or shut up. > >> Thirdly, WAAS coverage is for North America. > > Hint: Seaway ships operate only in North America, do not go on open ocean. > > And on open ocean, a single GPS is more than enough because you are not > concerned with cornering a sand bank or wall. _Your_ premise was the use of GPS for ship heading determination. That is what has been debunked here. Your selective editing aside. -- "If war is God's way of teaching Americans geography, then recession is His way of teaching everyone a little economics." ..Raj Patel, The Value of Nothing.
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| From | JF Mezei <jfmezei.spamnot@vaxination.ca> |
|---|---|
| Date | 2017-01-17 15:57 -0500 |
| Message-ID | <587e853e$0$10765$c3e8da3$5d8fb80f@news.astraweb.com> |
| In reply to | #98713 |
On 2017-01-17 07:44, Alan Browne wrote: > GPS does not allow for straighter routes than INS in the grand scheme of > things. Direct-to NAV predates GPS by a very long time. > > FANS is not about GPS. It's about communication (data links) so that > the positions of aircraft are accurately known in order to guarantee > separation. And the above is why it allows straigher routes. FANS allows for lesser separation because the position errors are lower. Lesser separation means that more flights can takle the straight route per hour meaning fewer flighst have to take the less efficient "scenic" route to stay away from traffic. > They were manifestly not using it to determine ship heading. Put up or > shut up. There was a discussion in sci.geo.satellite-nav newsgroup ages ago about this. > _Your_ premise was the use of GPS for ship heading determination. That > is what has been debunked here. Your selective editing aside. My use of heading was wrong, and I would mean direction of travel but that implies heading when you have 2 positions, in bow, one in sterm. I never said compass was not used. Having position and direction of travel for the bow and stern makes it easier for computer to calculate how much rudder is needed to make a bend while staying in the narrow channel and not hit a sand bank (which is common problem on St- Lawrence Seaway, especially in early season when they have shiften during winter),
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| From | Alan Browne <alan.browne@freelunchvideotron.ca> |
|---|---|
| Date | 2017-01-17 19:00 -0500 |
| Message-ID | <S8OdnWT6ysGALePFnZ2dnUU7-Q3NnZ2d@giganews.com> |
| In reply to | #98717 |
On 2017-01-17 15:57, JF Mezei wrote: > On 2017-01-17 07:44, Alan Browne wrote: > >> GPS does not allow for straighter routes than INS in the grand scheme of >> things. Direct-to NAV predates GPS by a very long time. >> >> FANS is not about GPS. It's about communication (data links) so that >> the positions of aircraft are accurately known in order to guarantee >> separation. > > And the above is why it allows straigher routes. FANS allows for lesser > separation because the position errors are lower. Lesser separation > means that more flights can takle the straight route per hour meaning > fewer flighst have to take the less efficient "scenic" route to stay > away from traffic. You're fabulating. Most separation takes place fore and aft, not laterally. > >> They were manifestly not using it to determine ship heading. Put up or >> shut up. > > There was a discussion in sci.geo.satellite-nav newsgroup ages ago about > this. There is a huge difference between feasibility and application. A "discussion" in an NG doesn't mean that ships use it. > >> _Your_ premise was the use of GPS for ship heading determination. That >> is what has been debunked here. Your selective editing aside. > > My use of heading was wrong, and I would mean direction of travel but > that implies heading when you have 2 positions, in bow, one in sterm. No. You were just bouncing shit around to see what would stick. > > I never said compass was not used. > > Having position and direction of travel for the bow and stern makes it > easier for computer to calculate how much rudder is needed to make a > bend while staying in the narrow channel and not hit a sand bank (which > is common problem on St- Lawrence Seaway, especially in early season > when they have shiften during winter), Funny, they've been managing without GPS for a long time. And now that they do have GPS, it is not at all in the way you fabulate about. -- "If war is God's way of teaching Americans geography, then recession is His way of teaching everyone a little economics." ..Raj Patel, The Value of Nothing.
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| From | JF Mezei <jfmezei.spamnot@vaxination.ca> |
|---|---|
| Date | 2017-01-17 23:40 -0500 |
| Message-ID | <587ef1a8$0$10625$c3e8da3$5d8fb80f@news.astraweb.com> |
| In reply to | #98725 |
On 2017-01-17 19:00, Alan Browne wrote: > You're fabulating. Most separation takes place fore and aft, not laterally. When you've got a bunch of flights going to Sydney or Hong Kong at roughly the same time, reduced separation allows you to put more of those flights on the straight route and reduce number of flights that have to take less efficient routes because the stright route is full.
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| From | Alan Browne <alan.browne@freelunchvideotron.ca> |
|---|---|
| Date | 2017-01-20 16:07 -0500 |
| Message-ID | <d-ednROwObOG4R_FnZ2dnUU7-LPNnZ2d@giganews.com> |
| In reply to | #98737 |
On 2017-01-17 23:40, JF Mezei wrote: > On 2017-01-17 19:00, Alan Browne wrote: > >> You're fabulating. Most separation takes place fore and aft, not laterally. > > When you've got a bunch of flights going to Sydney or Hong Kong at > roughly the same time, reduced separation allows you to put more of > those flights on the straight route and reduce number of flights that > have to take less efficient routes because the stright route is full. You have no sense of the scale involved. The use of FANS is mainly to ensure separation while aircraft are being re-routed while en route. In an INS only world it would work largely the same except that the lateral separation minima would be wider. In the grand scheme of things (lateral deviation over a 6500 NM flight) the precision of GPS v INS is meaningless where fuel consumption is concerned. The real advantage comes via planning for weather (wind) or changes in order to optimize fuel consumption or avoid bad weather. -- "If war is God's way of teaching Americans geography, then recession is His way of teaching everyone a little economics." ..Raj Patel, The Value of Nothing.
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| From | JF Mezei <jfmezei.spamnot@vaxination.ca> |
|---|---|
| Date | 2017-01-20 18:39 -0500 |
| Message-ID | <58829fbd$0$34712$c3e8da3$dbd57e7@news.astraweb.com> |
| In reply to | #98910 |
On 2017-01-20 16:07, Alan Browne wrote: > You have no sense of the scale involved. The use of FANS is mainly to > ensure separation while aircraft are being re-routed while en route. When FANS-12 came out, I read a lot of documents on the subject and the ability to allow more planes to use the direct route (with less separation) was one of the key features and would result in significant overall cost savings for airlines on long routes. The "re-routed" aspect is simply greater flexibility to designate the "shortest" route (based on winds) for the day and stuff as many flight as you can in that route. Sydney airport is very busy from 07:00 because of overnight curfew which means a lot of trans pac flights come in during about 3 to 4 hours in morning. And from north america, the north american to Fiji is also shared with traffic headed to/from New Zealand.
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| From | Alan Browne <alan.browne@freelunchvideotron.ca> |
|---|---|
| Date | 2017-01-21 08:01 -0500 |
| Message-ID | <MoadnanzI_Qvxh7FnZ2dnUU7-QXNnZ2d@giganews.com> |
| In reply to | #98920 |
On 2017-01-20 18:39, JF Mezei wrote: > On 2017-01-20 16:07, Alan Browne wrote: > >> You have no sense of the scale involved. The use of FANS is mainly to >> ensure separation while aircraft are being re-routed while en route. > > > When FANS-12 came out, I read a lot of documents on the subject and the > ability to allow more planes to use the direct route (with less > separation) was one of the key features and would result in significant > overall cost savings for airlines on long routes. > > The "re-routed" aspect is simply greater flexibility to designate the > "shortest" route (based on winds) for the day and stuff as many flight > as you can in that route. > > > Sydney airport is very busy from 07:00 because of overnight curfew which > means a lot of trans pac flights come in during about 3 to 4 hours in > morning. And from north america, the north american to Fiji is also > shared with traffic headed to/from New Zealand. You're just spinning micro facts to justify your erroneous view. Again, the benefits of FANS would be nearly identical with INS as they are with GPS. Of course the evolution of communications for aviation just happens to be roughly coincident with the evolution and integration of GPS. Note that FANS is also dependent on other things besides GPS - and those things are far more important than GPS. -- "If war is God's way of teaching Americans geography, then recession is His way of teaching everyone a little economics." ..Raj Patel, The Value of Nothing.
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| From | "Rod Speed" <rod.speed.aaa@gmail.com> |
|---|---|
| Date | 2017-01-22 08:13 +1100 |
| Message-ID | <eei18eFu0hvU1@mid.individual.net> |
| In reply to | #98920 |
"JF Mezei" <jfmezei.spamnot@vaxination.ca> wrote in message news:58829fbd$0$34712$c3e8da3$dbd57e7@news.astraweb.com... > On 2017-01-20 16:07, Alan Browne wrote: > >> You have no sense of the scale involved. The use of FANS is mainly to >> ensure separation while aircraft are being re-routed while en route. > > > When FANS-12 came out, I read a lot of documents on the subject and the > ability to allow more planes to use the direct route (with less > separation) was one of the key features and would result in significant > overall cost savings for airlines on long routes. > > The "re-routed" aspect is simply greater flexibility to designate the > "shortest" route (based on winds) for the day and stuff as many flight > as you can in that route. > > > Sydney airport is very busy from 07:00 because of overnight curfew which > means a lot of trans pac flights come in during about 3 to 4 hours in > morning. Yes, but that is fuck all in terms of planes actually on a particular route into Sydney. > And from north america, the north american to Fiji is > also shared with traffic headed to/from New Zealand. Still fuck all aircraft at a particular time on a particular route. FAR more on the high traffic routes across the atlantic.
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| From | JF Mezei <jfmezei.spamnot@vaxination.ca> |
|---|---|
| Date | 2017-01-21 17:40 -0500 |
| Message-ID | <5883e34a$0$59612$c3e8da3$460562f1@news.astraweb.com> |
| In reply to | #99001 |
On 2017-01-21 16:13, Rod Speed wrote: > Yes, but that is fuck all in terms of planes > actually on a particular route into Sydney. > Still fuck all aircraft at a particular time on a particular route. > > FAR more on the high traffic routes across the atlantic. FANS was first implented on trans-pac route. And these long routes provide potentitial for greater fuel savings. Allowing more planes to fly the most optimal route/altitude is a desirable thing. FANS has helped with that. Not sure the status on trans-atlantic routes. A good part is tracked by radar (but not all) whereas for trans pac, a huge part is not trackeed (same for indian ocean, and MH 370 couldn't be tracked to crash.
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| From | "Rod Speed" <rod.speed.aaa@gmail.com> |
|---|---|
| Date | 2017-01-22 21:03 +1100 |
| Message-ID | <eejebbF99fdU2@mid.individual.net> |
| In reply to | #99002 |
JF Mezei <jfmezei.spamnot@vaxination.ca> wrote > Rod Speed wrote >> Yes, but that is fuck all in terms of planes >> actually on a particular route into Sydney. >> Still fuck all aircraft at a particular time on a particular route. >> FAR more on the high traffic routes across the atlantic. > FANS was first implented on trans-pac route. Because if it did show any glitches, it wouldn’t matter as much there. > And these long routes provide potentitial for greater fuel savings. Irrelevant to your line about allowing less separation which you carefully deleted from the quoting. > Allowing more planes to fly the most optimal route/altitude > is a desirable thing. FANS has helped with that. But you were rabitting on about less separation and that clearly isnt the reason with that not being the problem with flights into Sydney. > Not sure the status on trans-atlantic routes. A good part is tracked by > radar (but not all) whereas for trans pac, a huge part is not trackeed > (same for indian ocean, and MH 370 couldn't be tracked to crash. Again, irrelevant to your line about separation that I was commenting on.
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