Archived from groups: alt.cellular.nextel (More info?)

I need a phone that displays lat and long only...no navigation functions or  
anything like that.  I see on the Nextel.com website that some phones say  
"supports GPS enabled applications and services".  Does that mean that the  
phone will display your current position, or do you need something like  
Telenav for that?  Also, is there a subscription for just the ability to  
display location or does the subscription just cover the programs like  
Telenav that do whatever it is that they do?
 
One more thing....from some of the comments that other people have made on  
various forums, I have heard that these Nextel phones w/ built-in GPS  
receivers are not very accurate.  Any truth to these rumors?
 
Many thanks!

Archived from groups: alt.cellular.nextel (More info?)

northd01 wrote:
> I need a phone that displays lat and long only...no navigation functions or  
> anything like that.  I see on the Nextel.com website that some phones say  
> "supports GPS enabled applications and services".  Does that mean that the  
> phone will display your current position, or do you need something like  
> Telenav for that?  Also, is there a subscription for just the ability to  
> display location or does the subscription just cover the programs like  
> Telenav that do whatever it is that they do?
>  
> One more thing....from some of the comments that other people have made on  
> various forums, I have heard that these Nextel phones w/ built-in GPS  
> receivers are not very accurate.  Any truth to these rumors?
>  
> Many thanks!  
>  
>  
My i58sr gives me Latitude and Longitude without special navigation  
software. It also states its estimated accuracy. I compared the accuracy  
with an IPAQ running Pharos navigational software and it compares  
favorably. My last location computation said 15ft for estimated accuracy.

Archived from groups: alt.cellular.nextel (More info?)

"stanmc" <stanmcn0spam@ameritech.net> wrote in message
news:cCxdd.13904$nP2.9648@newssvr15.news.prodigy.com...
> northd01 wrote:
> > I need a phone that displays lat and long only...no navigation functions
or
> > anything like that.  I see on the Nextel.com website that some phones
say
> > "supports GPS enabled applications and services".  Does that mean that
the
> > phone will display your current position, or do you need something like
> > Telenav for that?  Also, is there a subscription for just the ability to
> > display location or does the subscription just cover the programs like
> > Telenav that do whatever it is that they do?
> >
> > One more thing....from some of the comments that other people have made
on
> > various forums, I have heard that these Nextel phones w/ built-in GPS
> > receivers are not very accurate.  Any truth to these rumors?
> >
> > Many thanks!
> >
> >
> My i58sr gives me Latitude and Longitude without special navigation
> software. It also states its estimated accuracy. I compared the accuracy
> with an IPAQ running Pharos navigational software and it compares
> favorably. My last location computation said 15ft for estimated accuracy.
 
In addition I believe all the 3-digit models support GPS functions as you
stated

Archived from groups: alt.cellular.nextel,sci.geo.satellite-nav (More info?)

The Motorola i730 displays GPS latitude and longitude in degrees and
decimal minutes, to .001 minute. The coordinate system and datum
cannot be changed.
 
Unlike a conventional GPS receiver, the display won't show a real time
position. To take a fix, you select Refresh. After about 30 seconds a
beep sounds. At that time the screen shows your coordinates (not
altitude though), the time of the fix, and estimated accuracy in feet.
That screen can be viewed again at any time; all the data are retained
(even after a power off) until you do another Refresh. Other than
that, there's no provision for storing fixes.
 
These GPS fixes don't cost anything.
 
I don't know if the GPS portion of the phone continues to work when
the Nextel network is not in range.
 
For a quick accuracy check I took 4 fixes at random times in front
of my porch, at a place where the satellite view is good but not
great. Obstructions are a 1-story building and a couple trees still in
leaf. However, the view is practically clear above 30 degrees. I know
the coordinates of the spot to better than 1 meter accuracy. With the
i730 I got fix errors of 4 to 8 meters. The estimated accuracy
reported by the phone was sometimes better than the true accuracy,
sometimes worse.
 
The GPS also worked indoors under a rain-soaked wood roof. The one fix
I tried was 4 meters different from what a Magellan 315 receiver said.
 
That indoor fix was the only one I ever timed with a stopwatch. It
took 40 seconds from pressing Refresh to fix completion.
 
I can't offer anything on Telenav, since the Java app isn't on my
phone.

Archived from groups: alt.cellular.nextel,sci.geo.satellite-nav (More info?)

Paul Hirose wrote:
> The Motorola i730 displays GPS latitude and longitude in degrees and
> decimal minutes, to .001 minute. The coordinate system and datum
> cannot be changed.
>
> Unlike a conventional GPS receiver, the display won't show a real time
> position. To take a fix, you select Refresh. After about 30 seconds a
> beep sounds. At that time the screen shows your coordinates (not
> altitude though), the time of the fix, and estimated accuracy in feet.
> That screen can be viewed again at any time; all the data are retained
> (even after a power off) until you do another Refresh. Other than
> that, there's no provision for storing fixes.
>
> These GPS fixes don't cost anything.
>
> I don't know if the GPS portion of the phone continues to work when
> the Nextel network is not in range.
>
> For a quick accuracy check I took 4 fixes at random times in front
> of my porch, at a place where the satellite view is good but not
> great. Obstructions are a 1-story building and a couple trees still in
> leaf. However, the view is practically clear above 30 degrees. I know
> the coordinates of the spot to better than 1 meter accuracy. With the
> i730 I got fix errors of 4 to 8 meters. The estimated accuracy
> reported by the phone was sometimes better than the true accuracy,
> sometimes worse.
>
> The GPS also worked indoors under a rain-soaked wood roof. The one fix
> I tried was 4 meters different from what a Magellan 315 receiver said.
>
> That indoor fix was the only one I ever timed with a stopwatch. It
> took 40 seconds from pressing Refresh to fix completion.
>
> I can't offer anything on Telenav, since the Java app isn't on my
> phone.
 
Thanks for the information Paul. Living in Europe, we depend on this
kind of practical information, as we cannot test it ourselves.
 
--  
Andreas van Hooijdonk
http://www.gps-practice-and-fun.com

Archived from groups: alt.cellular.nextel,sci.geo.satellite-nav (More info?)

I wrote:
>  
> At that time the screen shows your coordinates (not
> altitude though), the time of the fix, and estimated accuracy in feet.
 
I should have also said the time and date are labeled "GMT". The page
shows the number of satellites used for the fix too. You have to
scroll down to see that, so I didn't notice it at first.
 
Much more is available if you put the phone in Trace Mode. This is not
in the manual, but the Motorola iDEN site explains how to activate
Trace Mode to check your software version.
 
http://idenphones.motorola.com/ide [...] lity.html#
 
Press the #, *, Menu, and Right Arrow keys quickly in that order. In
the Trace Mode menu, select GPS. That brings up a sub-menu:
 
Location
Time Info
Assist
Navigation
Summary
GPS Version
 
 
In Location I see:
 
Sat: 5 (number of sats in last fix?)
C lat: Nxx.01454
C lon: Wxxx.66167
SU lat: Nxx.00121
SU lon: Wxxx.70134
SU alt: 731 m
H acc: 6.1 m
V acc: 5.9 m
 
To conceal the exact location of my home, I used x for the integer
degrees in lat/lon. The SU coordinates are identical (+ or - 1 in
the last decimal place) to the fix displayed on the main GPS screen.
The "alt" is within a meter or two of my height above the geoid. But a
later fix said 693 m, which is much closer to my height above the
WGS84 *ellipsoid*.
 
When I put the "C lat" and "C lon" into a topo map program, it
indicated a hill about 3 miles from my home. There's a cell phone
tower on that hill! As well as I can judge by eye, the tower is
precisely at those coordinates.
 
 
In Time Info I see:
 
Epoch: 3754
Epoch 1/2: 0
Tz: -8.00 (standard time here is 8 hours behind UTC)
DST: 1 (Daylight Time is still in effect here)
Leap Sec: 13
Frame: 65
Slot: 13185
Accur: 32.25000
Gwk: 1293
Gtow: 580575.191660
 
I copied those numbers several hours ago; they update each time you
enter the page.
 
 
In SU Assist I see:
 
Data Valid: 0
SU lat: 0.00000
SU lon: 0.00000
H acc: 0.0 m
 
 
In Navigation I see:
 
Heading: 0
Velocity:0 kph
Vel Err:0 kph
 
 
In Summary I see:
 
11:09 am 10/23 (time and date)
Nxx 0.073 (lat/lon of last fix)
Wxxx 42.080
 
 
In GPS Version I see:
 
SiRF Cust SW
Version
v3.3.2.0
Falcon_2m
 
 
> i730 I got fix errors of 4 to 8 meters. The estimated accuracy
> reported by the phone was sometimes better than the true accuracy,
> sometimes worse.
 
Did another fix this morning. Actual error was 14 meters. The phone
said "Est Accur: 25 ft" and "Sats Used: 5". My Magellan 315 got 6 sats
at the same place.
 
At a better location the i730 used 7 sats and the Magellan 9 sats.
Couldn't test accuracy there, because I haven't done an accurate
postprocessed survey at that spot.
 
The 30 to 60 second delay I reported in my previous post was for the
first fix after power up. If you take a fix, then immediately take
another, it requires less than 5 seconds.
 
When the phone is taking a fix, it says "searching for satellites" but
there's no other feedback. All you can do is stand there and wait for
the beep. If it takes too long, press Cancel, move to a better
location.
 
According to the phone's instructions, "If possible, stand still until
your phone is finished determining your location. Moving your phone at
a walking pace while your phone is calculating your approximate
location may substantially decrease GPS performance. NOTE: Although
moving your phone at a walking pace decreases GPS performance, moving
it at the speed of a moving car does not."
 
"Your phone sends location information to your laptop or other device
using the standard National Marine Electronics Association (NMEA)
format. Your phone supports output messages in NMEA-0183 format and
supports the following NMEA-0183 sentences: GGA, GLL, GSA, GSV, RMC,
and VTG. The map software running on your laptop or other device must
support NMEA 3.0."

Archived from groups: alt.cellular.nextel,sci.geo.satellite-nav (More info?)

Paul Hirose wrote:
> I wrote:
>>
>> At that time the screen shows your coordinates (not
>> altitude though), the time of the fix, and estimated accuracy in
>> feet.
>
> I should have also said the time and date are labeled "GMT". The page
> shows the number of satellites used for the fix too. You have to
> scroll down to see that, so I didn't notice it at first.
>
> Much more is available if you put the phone in Trace Mode. This is not
> in the manual, but the Motorola iDEN site explains how to activate
> Trace Mode to check your software version.
>
>
http://idenphones.motorola.com/ide [...] lity.html#
>
> Press the #, *, Menu, and Right Arrow keys quickly in that order. In
> the Trace Mode menu, select GPS. That brings up a sub-menu:
>
> Location
> Time Info
> Assist
> Navigation
> Summary
> GPS Version
>
>
 
Thank you Paul. I really appreciate this information. Other readers too,
I hope.
 
--  
Andreas van Hooijdonk
http://www.gps-practice-and-fun.com

Archived from groups: alt.cellular.nextel,sci.geo.satellite-nav (More info?)

Since my last message, I've done a more thorough accuracy test on
the Motorola i730. Median error of my 20 fixes was 5.6 meters. (That
is, half the fixes were within that accuracy.)
 
I collected the observations during a 2 week period. Since the
satellites return to almost identical positions over the site every 24
hours, I was careful to scatter the time of day of the fixes as widely
as possible in order to get a random sample of satellite geometries.
 
Of the 20 fixes, 7 were after sunset, from twilight to almost
midnight. The others were during the day.
 
The test point is obstructed to the east by a wood building spanning
nearly 180 degrees of azimuth and about 30 degrees high at the closest
point. There is some signal penetration through the building; I've
gotten reasonable fixes inside with the phone. To the west and
northwest of the site are two trees about 30 degrees high. At this
time of year the foliage is thin. I believe the trees don't seriously
block the satellites.
 
For the correct coordinates of the test point I used the mean of
several postprocessed pseudoranging sessions with a Magellan Promark.
I'm confident the coords are accurate to better than 1 meter (1-sigma
uncertainty). Latitude of the site is about 35 degrees.
 
It helps a GPS receiver if you give it time to acquire all available
satellites. But I simulated a user who doesn't know any tricks to
optimize performance. In most cases my cell phone had been off for
several hours and I turned it on a few seconds before arriving at the
test point. A few times the phone was already on. However, in those
cases the GPS had not been used recently. As soon as possible after
turn-on, I commanded a GPS position refresh. (The GPS in the i730
doesn't run continuously.) Then I recorded the fix in my spreadsheet.
 
Immediately afterward, I also took a fix with a Magellan 315 for
comparison. The Magellan had an advantage over the cell phone: I gave
it time to lock on to all the satellites it could find. However, I
didn't use averaging. When I was satisfied the 315 had acquired all
available sats, I moved it a little to clear the average, then
immediately took a fix.
 
Here are the statistics for the 20 data points from the Motorola i730.
(The Magellan 315 values are in parentheses.)
 
Median actual horizontal accuracy: 5.6 meters (3.5 meters), or 18 feet
(11 feet).
 
Median estimated accuracy: 4.6 m (3.0 m), or 15 feet (10 feet).
 
The accuracy estimate you see on phone's display has only a weak
relationship with the actual accuracy of the fix. I discovered that by
dividing the 20 observations from the i730 into two sets of 10. The
"accurate" set contained the observations with estimated accuracy (the
value reported by the receiver) better than median, and vice versa for
the "inaccurate" set. Then I tabulated the median error (actual and
estimated) of both sets:
 
              "accurate" set                 "inaccurate" set
       actual error   est. error        actual error  est. error
i730      5.2 m          3.0 m              7.0 m       14.8 m
 
The "accurate" set is only slightly better than the "inaccurate" set,
though there's a large difference in its estimated accuracy.
 
There's no altitude on the GPS location screen, but you can read
altitude in meters by entering Trace Mode and going to the GPS menu. I
didn't collect statistics for that value.
 
I have not yet found a place with no cell service but a good view of
the sky, so I can't say if the GPS is independent of the cell towers.
 
Simple GPS navigation is possible with the Telenav application. This
is a Java program I found on the Internet. After I downloaded it to a
floppy, a wireless service center put it on my phone for a few
dollars. Most of the functions are disabled if you're not a subscriber
to the Telenav service, but you can save your location and navigate
back to it later. I used it one time to find my car on a parking lot
and missed by 10 feet.
 
The bearing of the destination is shown as a dot on the edge of a
circular "compass", and distance in feet or miles is displayed in
digital form. Unfortunately, the compass doesn't rotate to your
direction of movement. North is always up.
 
When the Telenav app is executing, the phone's GPS runs continuously.
 
If you need course and speed over ground, the GPS menu in Trace Mode  
can display that data. It's even possible to run Trace Mode and
Telenav simultaneously, so the course/speed screen periodically
overlays the Telenav compass screen, though I don't think that trick
is worth the trouble.
 
--  
 
Paul Hirose <ewwb4-khh25@earINVALIDthlink.net>
To reply by email delete INVALID from address.

Archived from groups: alt.cellular.nextel,sci.geo.satellite-nav (More info?)

Paul Hirose wrote:
> Since my last message, I've done a more thorough accuracy test on
> the Motorola i730. Median error of my 20 fixes was 5.6 meters. (That
> is, half the fixes were within that accuracy.)
>
> I collected the observations during a 2 week period. Since the
> satellites return to almost identical positions over the site every 24
> hours, I was careful to scatter the time of day of the fixes as widely
> as possible in order to get a random sample of satellite geometries.
>
> Of the 20 fixes, 7 were after sunset, from twilight to almost
> midnight. The others were during the day.
>
> The test point is obstructed to the east by a wood building spanning
> nearly 180 degrees of azimuth and about 30 degrees high at the closest
> point. There is some signal penetration through the building; I've
> gotten reasonable fixes inside with the phone. To the west and
> northwest of the site are two trees about 30 degrees high. At this
> time of year the foliage is thin. I believe the trees don't seriously
> block the satellites.
>
> For the correct coordinates of the test point I used the mean of
> several postprocessed pseudoranging sessions with a Magellan Promark.
> I'm confident the coords are accurate to better than 1 meter (1-sigma
> uncertainty). Latitude of the site is about 35 degrees.
>
> It helps a GPS receiver if you give it time to acquire all available
> satellites. But I simulated a user who doesn't know any tricks to
> optimize performance. In most cases my cell phone had been off for
> several hours and I turned it on a few seconds before arriving at the
> test point. A few times the phone was already on. However, in those
> cases the GPS had not been used recently. As soon as possible after
> turn-on, I commanded a GPS position refresh. (The GPS in the i730
> doesn't run continuously.) Then I recorded the fix in my spreadsheet.
>
> Immediately afterward, I also took a fix with a Magellan 315 for
> comparison. The Magellan had an advantage over the cell phone: I gave
> it time to lock on to all the satellites it could find. However, I
> didn't use averaging. When I was satisfied the 315 had acquired all
> available sats, I moved it a little to clear the average, then
> immediately took a fix.
>
> Here are the statistics for the 20 data points from the Motorola i730.
> (The Magellan 315 values are in parentheses.)
>
> Median actual horizontal accuracy: 5.6 meters (3.5 meters), or 18 feet
> (11 feet).
>
> Median estimated accuracy: 4.6 m (3.0 m), or 15 feet (10 feet).
>
> The accuracy estimate you see on phone's display has only a weak
> relationship with the actual accuracy of the fix. I discovered that by
> dividing the 20 observations from the i730 into two sets of 10. The
> "accurate" set contained the observations with estimated accuracy (the
> value reported by the receiver) better than median, and vice versa for
> the "inaccurate" set. Then I tabulated the median error (actual and
> estimated) of both sets:
>
>               "accurate" set                 "inaccurate" set
>        actual error   est. error        actual error  est. error
> i730      5.2 m          3.0 m              7.0 m       14.8 m
>
> The "accurate" set is only slightly better than the "inaccurate" set,
> though there's a large difference in its estimated accuracy.
>
> There's no altitude on the GPS location screen, but you can read
> altitude in meters by entering Trace Mode and going to the GPS menu. I
> didn't collect statistics for that value.
>
> I have not yet found a place with no cell service but a good view of
> the sky, so I can't say if the GPS is independent of the cell towers.
>
> Simple GPS navigation is possible with the Telenav application. This
> is a Java program I found on the Internet. After I downloaded it to a
> floppy, a wireless service center put it on my phone for a few
> dollars. Most of the functions are disabled if you're not a subscriber
> to the Telenav service, but you can save your location and navigate
> back to it later. I used it one time to find my car on a parking lot
> and missed by 10 feet.
>
> The bearing of the destination is shown as a dot on the edge of a
> circular "compass", and distance in feet or miles is displayed in
> digital form. Unfortunately, the compass doesn't rotate to your
> direction of movement. North is always up.
>
> When the Telenav app is executing, the phone's GPS runs continuously.
>
> If you need course and speed over ground, the GPS menu in Trace Mode
> can display that data. It's even possible to run Trace Mode and
> Telenav simultaneously, so the course/speed screen periodically
> overlays the Telenav compass screen, though I don't think that trick
> is worth the trouble.
 
Thanks Paul for sharing this valuable information and the trouble you
take to inform us.
 
--  
Andreas van Hooijdonk
http://www.gps-practice-and-fun.com