Garmin nuvi 2xx - yes, there IS a satellite screen!

dowtchaboy

This tip works with nuvi 250W - it probably works with ALL nuvi 2xx series and maybe more. As you know there on the nuvi 250W appears to be no way to access a "satellites" screen where the expected positions of the satellites are shown, and the strengths of the satellite signals are shown graphically - this is a standard feature on more expensive models. Well: press the green signal bars for at least 5 seconds and when you let go the satellite screen will pop up!




(sorry - don't know how to get this to appear in the message)

The pressing of the green bars needs to be fairly precise I have found - perhaps use a small finger or stylus.

As well as the signal strengths of 11 satellites (why 11?) it also shows estimated position accuracy and the position of the Sun and Moon.

Have fun!
db.

dowtchaboy

For those of you who simply must mess, here is another undocumented feature - a test/diagnostic section. However - go there at you own risk - I don't think you can damage it but you never know!

Press the green battery symbol for at least 8 or 9 seconds - you will then arrive at a test/diagnostic page with lots of further pages and some colour changing displays etc.

Here's a few photos (quality reduced to save downloading time):
DSCF0321.JPG

DSCF0322.JPG

DSCF0323.JPG

DSCF0324.JPG

DSCF0325.JPG

Cogita ante salis, caveat emptor, cave canem and so on....
BTW - anybody know how to get these files to display within the message body??

db.

Alun

dowtchaboy wrote: »

BTW - anybody know how to get these files to display within the message body??

You have to upload them somewhere and include the URL between IMG tags (use the Insert Image button at the top of the Advanced edit window). I usually upload to tinypic.com.



BTW doesn't the 2xx series have a screenshot feature? The 7xx series does, under Tools, Settings, Display. Saves you having to take pictures with your phone or whatever.

coylemj

If it's 11 satellites then it's probably because it's a 12-channel receiver and one of the channels is being used for the EGNOS (WAAS) satellite. There are suppoosed to be 24 active GPS satellites all the time so with a clear view of the sky all around you in theory 12 is the most satellites you could expect to be able to see at any given time (the guy in New Zealand can see the other 12), hence most GPS units can only track 12 satellites simultaneously.

Another possible reason for your display showing 11 satellites is because that might be the number of satellites currently above the horizon where you happen to be at that point in time, the satellites are not spaced out evenly so it's possible for there to be less than 12 above the horizon at a given time. You'll need to keep an eye on that satellite screen from time to time - if it never goes above 11 then the EGNOS satellite (PRN 120/Garmin 33) is hogging the 12th channel.

Alun

It's quite simply because there were only (potentially) 11 satellites in view from that location at the time the picture was taken according to the almanac (count 'em!). AFAIK nuvi's don't use WAAS/EGNOS.

coylemj

Alun, there is a WAAS/EGNOS option (enable/disable) on the higher spec. Nuvis so what you say is not 100% correct, we just don't know if the 2xx series uses WAAS or not but the 3xx, 6xx and 7xx models do have it.

If anyone wants to find out when there will be a good set (maybe >12) of satellites above the horizon, download Trimble Planning......

http://www.trimble.com/planningsoftware.shtml

Alun

coylemj wrote: »

There is a WAAS/EGNOS option (enable/disable) on the higher spec. Nuvis so what you say is not 100% correct, we just don't know if the 2xx series uses WAAS or not.

Which is why I said AFAIK :rolleyes: My nuvi 760 doesn't have that option and that's a pretty high spec one I'd say. Maybe with the newer high sensitivity SiRF III receivers they (rightly) decided that it was a bit of a waste of time anyway on an automotive GPS and got rid of the option to enable/disable it?

dowtchaboy

Alun wrote: »

BTW doesn't the 2xx series have a screenshot feature? The 7xx series does, under Tools, Settings, Display. Saves you having to take pictures with your phone or whatever.

Yes Alun - you are quite right - the 350W does have screen capture - via Tools, then a button appears on the top right of the screen. Thanks.

BTW - I think it must have been your post on this board that alerted me to the satellite screen access method - and then I forgot where I saw it! Sorry!:o
db.

coylemj

Would agree and in fact WAAS uses more juice so they've probbaly disabled it because in the 3xx manual they say that: 'turning on the WAAS/EGNOS might (my italics) improve accuracy but it consumes more battery power.

So I'd say they've disabled it. The big benefit of WAAS is that the altitude reading is far more accurate than with WAAS switched off but since auto units don't even calculate altiitude, it's a waste of battery power picking up the signal and processing the data.

Alun

coylemj wrote: »

So I'd say they've disabled it. The big benefit of WAAS is that the altitude reading is far more accurate than with WAAS switched off but since auto units don't even calculate altiitude, it's a waste of battery power picking up the signal and processing the data.

Not quite true. Elevation is calculated at a much lower level, in the GPS module itself .. it's part of the standard datastream supplied to the main unit along with position, velocity, satellite info etc. and nothing to do with the higher level software in the unit that presents the maps, does the routing etc., so it's being calculated anyway as part of the fix, for free if you like. In fact you can see it on the satellite screen I posted above. You'll also notice that if you mark a waypoint (favourite) while you have a fix, it'll save the elevation as well as part of the data (you can see it in the GPX file) so it's getting through to the main unit's software, although it isn't doing much with it apart from that apparently.

DannyBuoy

dowtchaboy wrote: »

... press the green signal bars for at least 5 seconds and when you let go the satellite screen will pop up!...


db.

Cheers db, was thinking that would be a nice feature to have, my 250W didn't (as i thought). Does now tho! Well spotted.

dowtchaboy

I cut and pasted the below stuff from
http://www.gpspassion.com/forumsen/topic.asp?TOPIC_ID=54708
Hope you find it useful!

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.......Ok I'll try but I'm no expert:

- the green icons are the satellites that the nuvi is locked onto
- the gray icons are the satellites that the nuvi can see but can't lock on to
- icons flashing grey/green are ones that the nuvi is attempting to lock on to
- the icons are shown in there position in the sky from your present location
- the small round icon with the red centre is the direction your facing/travelling
- the sun icon is the position of the sun from your present location
- the moon icon is the position of the moon from your present location
- number in the top left is how fast your going (0.0 if your stationary)
- number in the top right is your current elevation
- numbers in the bottom left are your current location (Latitude and Longitude)
- bars on the right side are signal strength of the locked in satellites

Hope these are all accurate (sure we'll hear if they aren't) and is what you were after.
Edited by - NanaimoRick on 04/29/2006 04:58:09

Rick, Thanks. That is very helpful. I took a drive and things now make sense on this screen.

- I assume that I'm at the center of the circle.
- The red outside circle (which moves) is the direction of my movement.
- If I orient myself and the unit in the direction of N, then the sun and moon are properly oriented in the sky.

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All satellites, for which there's a signal bar, are locked on to (correlation completed). However, the hollow bar shows that ephemeris data (precise orbital information) has not yet been downloaded from the satellite. Thus, it can't be used for the PVT equation yet.
When the signal bar gets solid, the data is available, and the satellite may, but not necessarily, be used to compute position, velocity and time.

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I find this screen useful for monitoring Nuvi's progress when acquiring satellites, but I don't see why it would matter that the only orientation is North-up. Am I missing something?

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Naah.It is not THAT important. But once you are used to a screen where you can see which direction you are heading (of course this info is available in another screen) in graphical representation; and the sun and the moon in the right orientation to your vehicle, and the satellites too...it's kinda nice.

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I have found one useful function of the sat page. It serves as a solar/moon compass. Point the sun icon toward the sun or moon and you can see where true north is. This, of course, depends on clear enough conditions to see them. Especially handy out in the field when laying out site plans.
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db. (this is all the work of others - I just gathered it together)