It's a regression
I have a Garmin GPS from 1983, it still knows what the date is just fine!
Garmin's Geko 201 GPS kit can't decide what year it is, flipping between decades every time it's switched on, though it's performing better on days of the week. Garmin Geko 201 Thanks to Reg Reader Dazed for the piccy 2010 is proving a complicated year for computers, fouling up debit cards in New Zealand and credit cards …
My dad has one of these. The problem is not the software update, whenever its available, its the cost of the data cable to connect it to the computer. Garmin charge £34 for the PC cable, and another £37 to convert from rs232 to usb. Thats about what we payed for the Geko 201 in the first place!
where I found a suitable cable for, roughly, 5 quid (maybe excluding shipping, but it came in an envelope, so postage wasn't that much either). USB-RS232 converters can be had for a similar sum.
And there's the reputable outdoor shop who will gladly apply the patch if you bought the unit there. When I bought my CSx60 the shop assistant took it out of the box, connected it to a laptop and checked if it was at the newest software level. He also made some initial settings (which he explained to me and asked how I'd like them set).
My Geko 101 is showing similar symptoms. On power on the date/time flicker rapidly between
several dates in the past, it took ages to lock on to 4 satellites, and the time is now being shown
as 14:48:57 24-Apr-08 (actual is Mar 10 12:50:34 GMT 2010)
Position is correct.
There is no computer interface on the 101, so how Garmin are going to fix this I don't know
> There is no computer interface on the 101, so how Garmin are going to fix this I don't know
They have offered to upgrade to a 301 for £50.00
I only really use the GPS for two things: how far I have to trudge back to the car at the end
of the day, and in case of emergency. If I'm in a whiteout on the summit of the Ben and I'm trying
to get to the top of the zig-zags at NN 1565 7131 whilst avoiding Five Finger Gully, I don't
want to be wondering if my GPS had decided to throw a wobbly, so despite having been made
redundant a fortnight ago I think I'll be taking up the offer.
There's no need to own a computer in order to use one of these devices so why should the updates only be available via download. Hopefully Garmin will offer users without computers an update free of charge. The only way to do that would be to offer a free returns program. No way should users be charged for postage or have to pay travel costs to their nearest dealer.
I get very bored of manufacturers who think that offering a free download to fix a problem is enough. Not everybody is connected to the internet and those who are not should not be penalized.
Not only do you have to own a computer, but Garmin expect you to be running a supported OS and browser.
| Compatible computers and Internet browsers:
| IBM-compatible PCs running Windows® XP or Vista operating systems
| with Internet Explorer 6+ or Firefox 1.5+
| Intel-based or PowerPC G3 or later Mac OS 10.4 or later with Firefox 2.0+ or Safari 2.0+
"Not only do you have to own a computer, but Garmin expect you to be running a supported OS and browser"
Agreed, but to be fair, the fact you DO get some update is worthy of a smiley stamp. Some vendors only care you've bought it, after that, who cares? They certainly don't.
Not making downloads available, will that solve the problem? It's not like a GPS works both ways, and Garmin could track you down to personally upgrade your device.
So *if* you know of the problem, it's not that hard to ask an acquaintance with a pc (or visit local library) and search for explanations and hopefully update the problem away --- not using windoze I have to do the same once in a while. The problem is whether you invested in a data cable to make the connection, but once again: it's not like out-of-warranty problems get usually fixed for free, internet or not --- not making things available for free is not a solution.
/I'm dictating this via megaphone, as I also have never been on those intertubewebs.
Your only going to get about 6 months guarantee under current legislation.
I see reviews of this device from 2003 so getting 7 years out of a product these days is not bad.
If you don't like the throw away society we have then write a letter to an MP or something. Expecting a manufacturer to do something is just wishful thinking really.
If you want to know the distance between one sender and one receiver, you are correct. You would need an accurate clock. However if you have multiple senders which you know where are you can calculate the distance and direction if you know the difference in distance to each sender. The difference in distance can easily be extracted from the signals you receive. Basically what you end up with is a set of equations with one equation for each satellite you have.
I do not know exactly how GPS is implemented, but I am quite confident it is possible to implement it without a clock in the receivers all together. However it might be possible that they use an accurate clock to measure the time difference between the different satellite signals. If they for some reason do, that clock would not be synchronized though as that would be nearly impossible to implement.
Most have a real time clock as well as a high precision clock used to do the satellite tracking. The realtime clock is a crappy thing like what's in your PC/PDA . The tracking clock is more typically a much more accurate TCXO from Rakon or similar.
The TCXO does not have to be calibrated for real time since it is not measuring the range between the satellite and yourself, but is instead measuring the **difference** in the range from you to satellite A and satellite B. That tells you that A is, say, 2507 metres further away than B and A is 457789 metres further than C and so on.. These differences get fed into a bunch of simultaneous equations etc which figure out where everything is.
The TCXO does not have to be atomic accurate since the tracking logic has to handle clock error anyway due to the doppler effect of moving satellites.
GPS measures the difference between the very accurate clocks on each sataleite to get your position - it doesn't need it's own clock.
Except - the actual date is sent as a number of weeks since GPS started (about 1980) and then hours, mins etc. The GPS week field wrapped around just before Y2K.
they recently increased the number of bits sent in this field so my guess is that the Garmin is overflowing and interpreting this as a signed number
"the receiver must have a very highly tuned clock to know the difference between the time signals broadcast by the satellites."
No, a time *DIFFERENCE* is exactly the same regardless of the base line you choose to use to measure the two points from. Add a day, a month or a year or decade into the equation and it makes no difference because what you add you also subtract too.
In any case, I suspect that the device receives a correct date from the satellites, but in a coded form and it is the decoding of the date data (purely for display and logging purposes) where the error occurs.
Actually, Tom Tom refuse to acknowledge that a computer device like a SatNav has any need of knowing what the date is. It acquires the time from the Satellite (or you can set it manually), but there's no way to set the date. This means that when you connect the device to your PC, all the dates have stupid timestamps on them.
I raised this as a support issue with them, but they refused to accept that it was a bug.
This is on a TomTom 301, a bit out of date now, but still going strong.
GPS receivers normally do have real time clocks, it helps the time to first fix if you know what time it is and have a valid empheris (list of where the satelites are) from the last fix.
Plus a real time clock is built into the SOC and you have a battery anyway so it's not exactly a challenge to implement - of course the maker might not bother to write software to let you set it.
Another wrinkle, GPS time doesn't include leap seconds so is currently about 15secs out. The new satelites broadcast this correction but older/cheaper receivers might not use it.
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I have a Geko 201, with older 2.50 firmware, tried it out today, date shows as 24 April 2008.
However I downloaded the test route, I rode today, onto the pc and reading them in GPS Tracker, the dates and times are all correct. Well a uniform hour out, but I think I haven't got it set corectly vis GMT and UTC.
So unless it starts acting up, I don't see this as an issue, I have a wristwatch/Calender for the correct date.
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