GPS While Running Track Laps?

warp wrote I've been researching the Timex Bodylink and
Forerunner GPS systems, and I am wondering if they
correctly register distance traveled while running laps on
a 1/4 mile track. Seems like they might possibly be
confused by the relatively short circle... does anyone have
any information on this?

I used my Timex on a track and it had no problems.
Kristine Quilici

On Mon, 26 Apr 2004 16:27:57 -0700, "warp" <[email hidden]>

Quoted message said:

I've been researching the Timex Bodylink and Forerunner
GPS systems, and I am wondering if they correctly register
distance traveled while running laps on a 1/4 mile track.
Seems like they might possibly be confused by the
relatively short circle... does anyone have any
information on this?

I've used the Garmin Forerunner for running 800m sprints
which I split into 400m out and 400m back along a road. It
had no problem with this.

HTH Russell

warp said:

I've been researching the Timex Bodylink and Forerunner
GPS systems, and I am wondering if they correctly register
distance traveled while running laps on a 1/4 mile track.
Seems like they might possibly be confused by the
relatively short circle... does anyone have any
information on this?

It's not a problem...unless there are obstructions in the
path of the receiver, like a building. The University of
Michigan Track has a building 5 feet from the edge of the
track, and I can be off by as much as 1/20th of a mile per
lap because of the obstruction caused by the building.

-je-
remy

--
--
+================================================================+
Jeremy Hallum, System Manager , Astronomy, University of Michigan
[email hidden]::[email hidden]
"Audentis Fortuna Iuvat"

warp said:

I've been researching the Timex Bodylink and Forerunner
GPS systems, and I am wondering if they correctly register
distance traveled while running laps on a 1/4 mile track.
Seems like they might possibly be confused by the
relatively short circle... does anyone have any
information on this?

Why would you need a GPS unit for running laps? You already
know how long a lap is, and can count, and a simple watch
will give you pace.

--
Bob Burns Mill Hall PA [email hidden]

On Mon, 26 Apr 2004 16:27:57 -0700, "warp" <[email hidden]>

Quoted message said:

I've been researching the Timex Bodylink and Forerunner
GPS systems, and I am wondering if they correctly register
distance traveled while running laps on a 1/4 mile track.
Seems like they might possibly be confused by the
relatively short circle... does anyone have any
information on this?

For information on Running with a GPS checkout
www.GPSrunner.net

there is a yahoo group dedicated to the forerunner, google
this group for the link. if I remember correctly the
accuracy is sufficent enough to be affected by which arm you
are wearing it on.

warp said:

I've been researching the Timex Bodylink and Forerunner
GPS systems, and I am wondering if they correctly register
distance traveled while running laps on a 1/4 mile track.
Seems like they might possibly be confused by the
relatively short circle... does anyone have any
information on this?

"warp" <[email hidden]> wrote in message news:<[email hidden]>...

Quoted message said:

I've been researching the Timex Bodylink and Forerunner
GPS systems, and I am wondering if they correctly register
distance traveled while running laps on a 1/4 mile track.

Yeah, you wouldn't want to risk getting lost, so a GPS is a
must for any track runner.

I have both the Timex and Garmin and ran a 10K on the track
to check the calibration wearing both at the same time. Both
read high. I can't recall the exact numbers but the Timex
was about 99.5% accurate and the Garmin was way off, I seem
to remember about 95%. The Garmin could not handle the oval
very well. All of my running loops that I have show about
.05 to .1 longer using the Garmin vs the Timex. I have used
the Timex in several certified marathons and it read about
.1 to .15 over at the end which is pretty good over 26.2
miles. Have not used the Garmin in a marathon yet. My
experice is that the Timex is quite accurate and I am
certain that my Garmin is consistantly optimistic in
mileage. Also the measurement varies more over the same loop
where as the Timex measures virtually identical each time.
I'm not sure if accuracy would vary from unit to unit and
other people would have better or worse accuracy.

"warp" <[email hidden]> wrote in message
news:<[email hidden]>...

Quoted message said:

I've been researching the Timex Bodylink and Forerunner
GPS systems, and I am wondering if they correctly register
distance traveled while running laps on a 1/4 mile track.
Seems like they might possibly be confused by the
relatively short circle... does anyone have any
information on this?

Gee, that frustrating feeling that you're running around
in circles must really intensify when you actually have
proof of it.

"Bob Burns" <[email hidden]> wrote in message
"]news:[email hidden]...

Quoted message said:

warp said:

I've been researching the Timex Bodylink and
Forerunner GPS

systems,

Quoted message said:

Quoted message said:

and I am wondering if they correctly register distance
traveled

while

Quoted message said:

Quoted message said:

running laps on a 1/4 mile track. Seems like they might

possibly be

Quoted message said:

Quoted message said:

confused by the relatively short circle... does anyone
have any information on this?

Why would you need a GPS unit for running laps? You
already know

how long a

Quoted message said:

lap is, and can count, and a simple watch will give
you pace.

That only works if can stay in a single lane. If you have
change lanes to get out of the way for a faster runner and
the distance could end up a few feet longer. That can create
a great deal of angst for those "precision" people. The
actual mile could end up being 5,284 feet and raise havoc in
ones log book. 😉

--
Doug "tongue way in cheek" Freese "Caveat Lector"
[email hidden] (remove the NOBS)

"Bob Burns" <[email hidden]> wrote in message
"]news:[email hidden]...

Quoted message said:

warp said:

I've been researching the Timex Bodylink and Forerunner
GPS systems, and I am wondering if they correctly
register distance traveled while running laps on a 1/4
mile track. Seems like they might possibly be confused
by the relatively short circle... does anyone have any
information on this?

Why would you need a GPS unit for running laps? You
already know how long

a

Quoted message said:

lap is, and can count, and a simple watch will give
you pace.

--
Bob Burns Mill Hall PA [email hidden]

Good question Bob; I often run to the track from my home, do
some laps, and then head out on a road course (not quite
sure WHY I do this, but what the heck, it works). And I
would be interested in total distance traveled plus the
track distance.

On Tue, 27 Apr 2004 12:59:09 -0500, [email hidden] (Bumper)

Quoted message said:

there is a yahoo group dedicated to the forerunner, google
this group for the link. if I remember correctly the
accuracy is sufficent enough to be affected by which arm
you are wearing it on.

The Yahoo Group is www.groups.yahoo.com/groups/GarminF

also see www.GPSrunner.net and www.GPSbiker.net

John

Bob Burns said:

Why would you need a GPS unit for running laps?

No one "needs" these toys... But, the word that is
pronounced "need" is often spelled "w a n t".

And, having a new toy, most boys cannot resist the
temptation to play with it.

[email hidden] (Bumper) wrote in
:"]news:[email hidden]:

Quoted message said:

there is a yahoo group dedicated to the forerunner, google
this group for the link. if I remember correctly the
accuracy is sufficent enough to be affected by which arm
you are wearing it on.

warp said:

I've been researching the Timex Bodylink and Forerunner
GPS systems, and I am wondering if they correctly
register distance traveled while running laps on a 1/4
mile track. Seems like they might possibly be confused by
the relatively short circle... does anyone have any
information on this?

During yesterday's track workout I wore my Forerunner. I
found it to be off anywhere from 3 to 12% too long. I wear
the GPS on my right arm and I ran in the middle of lane 1
for most of the laps. When I imported the data onto the
Forerunner software, the start and end of each lap never
where at the same point. The end point was always at least
50 meters short of the start point of each lap. The device
seems to be much more accurate on an out and back or a long
loop course where there aren't a lot of turns.

Phil M.

--
"Pain is temporary: the success it brings can be
everlasting." -fortune cookie

In article said:

That only works if can stay in a single lane. If you have
change lanes to get out of the way for a faster runner and
the distance could end up a few feet longer. That can
create a great deal of angst for those "precision" people.
The actual mile could end up being 5,284 feet and raise
havoc in ones log book. 😉

If it's a metric track, you're more than 30 feet short to
the mile anyway (-; And you'd better stay at exactly the
right distance from that white line.

Cheers,
--
Donovan Rebbechi pegasus.rutgers.edu~elflordOpen ↗

Quoted message said:

No one "needs" these toys... But, the word that is
pronounced "need" is often spelled "w a n t".

And, having a new toy, most boys cannot resist the
temptation to play with it.

Agreed, they are a luxury, but can also be very useful. When
I was training for my first ultra-marathon recently, I was
following a training program. When I needed to run say
20kms, I did not need to measure a route. I just went out
and ran. It was great. I did random routes and still knew
how far I ran. And I came back knowing just a little bit
more of the neighbourhood. I have really good memories of
some of those ad-hoc runs.

Cheers, Russell.

Another effect I recently observed that I didn't see anyone mention here is that the filtering done on the GPS data will make it seem like you've run less than a full-size track. As you run around the track, the moving average of your position will be consistently closer to the center of the oval. The effect can be substantial, as seen in this image. Granted, my data may be particularly bad (it's a phone-based GPS after all) but you will get a similar effect from any device that uses a moving average. In this case I was confused why my easy run to the local track and my hard four laps both seemed to be at the same pace -- turns out the GPS thought I was running on a 320m track!

[IMG]cyclingforums.com700Open ↗[/IMG]

It's very likely that a dedicated GPS unit for sports would have recorded an accurate track as such units very likely sample at much higher rates than the GPS unit in your phone. Given the vast number of GPS units specifically for running and relatively low number of complaints such as yours, it would seem what you experienced is because you used a phone based GPS. It's not surprising that a phone wouldn't sample GPS signals and calculate track data (like distance, speed, et al) as quickly as a dedicated unit would since a phone has to provide power to many other functions. A bike computer or running watch are very simple and have relatively simple power demands in comparison.