Walkers: Clip-on firmware upgrade may be inappropriate

CheshireCat

Shortly after successfully flashing my Clip-on to V2, I saw a post from DW4444 mentioning concerns about use for hiking/walking. I have now had time to check out the reflashed device. I use this in conjunction with Memory-Map OS on an iPAQ 4150. Because my main use is walking, I have only used XT mode in the past.

When walking, it seems to be very slow at responding to movement. What is worse, it is often way off track (100m plus) for several minutes at a time. This happens both where there is heavy tree cover and where lots of sky is visible. Version 1 could occasionally "lose the plot", somtimes quite spectacularly but I found it pretty close to the line on the map most of the time. Version 2 seems to be off line substantially more often.

Once in the car and driving, the line given by V2 corresponds very closely to the road, though there is a tendency to cut corners more than with V1, perhaps in line with the slight increase in lag seen while walking.

<guess the reason>Perhaps the new firmware is doing some clever averaging based on an assumption that the receiver will either be moving at vehicular speed or not moving at all </guess the reason>

Overall, if we had been having a quiet pint down at the Square and Compass, I reckon you might not have gone straight home to reflash your Clip-On.

I hope someone will tell me that there's an easy correction for this but for the present, I think it will have to be ST mode for walking. Incidentally, the thorns from Blackthorn or Hawthorn bushes are the best tools I have found for changing from ST to XT 8-}

Regards

DW4444 · Occasional Visitor Joined: Aug 24, 2004 Posts: 8

Glad someone else is concerned about us walkers !

I've asked Fortuna to release the old code again but have as yet had no response (only a day or two ago).

I'll let you know if I receive it.

MikeB · Posted: Thu Aug 26, 2004 9:57 pm Post subject:

Oh dear

I am glad that I haven't had time to try out the upgrade. Just before I went on holiday I considered doing it but didn't have time. Now I am glad I didn't.
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Mike Barrett

TC · Posted: Thu Aug 26, 2004 9:57 pm Post subject:

Interesting...

As I said in a previous post I use my Clip-on on my mountain bike and in the car. On the bike - which could be thought of as half way between car and walking - the Clip-on is every bit as good at v2 as it was at v1 in some ways better and I wound say never more that 30m out.

I'll be cycling this weekend but if I get a chance I'll see what I get while walking in the Scottish Islands - would be good it the upgrade to v2 made the Clip-on more waterproof Laughing

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DW4444 · Occasional Visitor Joined: Aug 24, 2004 Posts: 8

I agree that the V2 performance appears better under open skies. My problems occurred specifically when reduced signal situations under trees or with the GPS in my pocket.

CheshireCat's experience does seem even worse.

HellFire · Regular Visitor Joined: Jul 25, 2004 Posts: 126

I was thinking of getting a Fortuna but after reading this I don’t thing I will I’ve only got a normal receiver and I would say it’s not normally 15 feet out and it works very well in my pocket

jlw · Posted: Fri Aug 27, 2004 5:33 pm Post subject:

agreee.... i hate it toooo !!! while walkning...
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DW4444 · Occasional Visitor Joined: Aug 24, 2004 Posts: 8

I contacted Fortuna and they did kindly supply me with the old XT V1 code.

I haven't yet tried to downdate back to V1 so can't yet comment on the technical feasibility but I did see that ForestRanger on GPSPassion had succeeded so it should be OK. If anyone else is intersted in doing so I can email you the .s file.

I still think that Fortuna are to be congratulated on making upgrades and on talking to individual users. I suggested that they could consider setting up a beta test group from pocketgps members before releasing code to the wider community. I'll see if anything comes of it.

Ole · Occasional Visitor Joined: Sep 07, 2004 Posts: 2

I have a few comments about the Fortuna Clip-on GPS, XT version 1 vs. version 2.

Although I do not use it for pedestrian use, but instead in my sailing boat, the speed is slow and approximately the same as for walking (typically 4-5 knots ~ 6 - 8 km/hr.)

The GPS unit is placed inside the cabin and is therefore covered by 2 layers of fibreglass and some form of distance material (2 cm of balsa wood)
Pocket PC is HP2210 and the navigation program is OziExplorer CE version.

Inside the boat there is no problems with signal strength. The GPS works fine in ST as well as in XT mode.

BUT after upgrading to XT version 2 the output on both position, heading and speed has become very noisy. Graphically it looks just like 'white noise' and that causes the navigation program to log up to 15 times more often than before and therefore producing huge track-log files that of course can be filtered but they are still 'noisy'.
ST mode also produces noisy tracks at low speed, but less noisy than XTv2

On the other hand: I do not see off track of more than a few meters, compared with my Garmin GPS128.

After some mails with Fortuna, I finally received the file for 'downgrading' back to XT version1 and after reverting back to version 1 all is back to normal.

If using the XTv2 at higher speed, for example in my car or even at a bicycle the noise is very much less visible at a graph (e.g.. speed vs. time).
The drawback is that at very low speed (< 1 knots ~ 1,8 km/hr), the GPS output speed = 0, but that is similar to the speed display on my bulkhead mounted classic Garmin GPS (GPS 128) at auto speed filter.

So my recommendations must be:
If using at low speed, say < 15 km/hr, use XT version 1.
If average speed > 15 km/hr, the XT version 2 is better, because there is almost no more lag in the output, and the sensitivity is also some better, I think.

Best regards

Ole, Denmark

Biggles_no1 · Occasional Visitor Joined: Jan 12, 2004 Posts: 8

I am glad that I have seen this thread because I was getting ready to throw this clip-on out of the window.

While I am impressed with its ability to lock on quickly and stay locked I am really really disapointed with its accuracy. So much so that I just can't trust what it says.

When using TomTom V3 software, the direction arrow is pointing the wrong way for more than 60% of the time and it often puts me as much as 300 yards away from my current location, even with 9 sat lock and in wide London Roads. On a few occasions I started walking for about 3-4 mins and the thing hadn't even registered I'd moved at all.

In fact walking back to work across London Bridge The GPS put me in the Thames and swimming to shore about 200 yards away Embarassed

Although quite amusing at the time it's not too helpful.

Although the TOMTOM bluetooth GPS is less sensitive I could pretty much always trust it to tell me where I was.

So perhaps its a firmware issue? According to the serial number I have v2 firmware so would the experts recommend using an earlier version. If so how, exactly, do I go about doing this?

Many thanks

Jason

Biggles_no1 · Occasional Visitor Joined: Jan 12, 2004 Posts: 8

I forgot to say that my comments above, were with regard to the xtrac mode.

This afternoon I switched over to standard mode and left it by the office window for the last couple few hours. It took a good hour to actually find lock but that's from within the building so I'm fine with that. Although it only has a 3 sat lock and does drop in and out every 40 seconds or so it's a heck of a lot more accurate than XT mode. The position hasn't wandered more than about 100yards at most for the last 2 hours.

I tried the same thing in XT mode the other day and was amused to watch the GPS wander down the road for half a mile or so all by itself Confused

My earlier comments still stand though. I would like xtrack for lunchtime walkabout so I'm thinking more and more that I'm needing V1 either that or XT mode is stuffed on this device.

Comments anyone?

DevilsAdvocate · Posted: Thu Nov 04, 2004 4:36 pm Post subject:

I have only tried walking with mine once. I was using a 50K Memory Map (OS verson of the software). It was spot on , no problems. I have noticed that the 25K map of where I live seems to be about 50 ft out to the south.
I am in the Lakes in a coupke of weeks so I will try out the 25K and 50K while walking and let you know the outcome.

This is all in XT mode. Also never have any problems driving with TT3.

Regards
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DevilsAdvocate · Posted: Thu Dec 23, 2004 4:17 pm Post subject:

Ok

I have tested walking both around Darwen and in the Lakes using both the 25K and 50k Ordnance Survey maps (Memory Map). I'm not completely convinced there is a problem. Much of the time the track was pretty much spot-on. Obviously 50K seemd more accurate as its not as detailed.

The 2-3 issues I found where as follows:

1) Walking round Tockholes (Darwen) the track deviated from the map significantly in one point . However the map showed the path following a wall which it didn't on the ground - my guess mapping inaccuracy

2) There was one point where it showed me on the wrong side of a river bank - gps accuracy rather than V2 issue , may be?

3) Walking round Tarn Hows in the lakes the gps track was very accurate apart from one point where it placed me between the path on the map and the tarn. Now on the ground this was obviously a mapping inaccuracy or an un-mapped path, definitely not a gps issue.

All in all I feel the accuracy in V2 is adequate (based on these basic tests), both tracks where in wooded although not heavily foliaged (time of year). Of course neither walk warrants uses of a GPS but they were useful tests done while out walking with the family.

Regards
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IPAQ 2210
TTN3
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