GPS help and advice

satmap have this to say today which may also be of interest to the fisher-price pooter users.

my use of bold.

"Today, Satmap is launching our latest software for SatSYNC and the entire Active 10 GPS series (Active 10; Active 10 PLUS and the newly launched Active 10 BIKE). Version 1.4 is now available for free download for all UK customers. The European version is in the final phase of development and testing and will be ready in February 2010. For UK Mac users, you can get this software via an SD card. We appreciate the amazing patience of our Mac users and hope to reward them with launching the promised Mac compatibility for the Active 10 before the end of the year.

New features on version 1.4
- Geocaching is made easier.
- Map Toggling.
- Red light option for night use.
- POIs now have a library of icons available for download, giving faster identification of POIs.
- New hibernate mode stores satellite data for up to 8 hours and puts the operating system on standby.  When the unit is switched back on you will see an instant map screen and a GPS fix within seconds.  A unit on standby will give around 100 hours of usage.  (There is a £9.99 charge for this feature)!"

£9.99 charge - you're taking the piss yet again satmap.

> New hibernate mode stores satellite data for up to 8 hours and puts the operating system on standby.  When the unit is switched back on you will see an instant map screen and a GPS fix within seconds.

Ermmmm...  I'd expect any decent GPS receiver to store satellite ephemeris and almanac data when it's turned off, so that it can perform a warm start when next turned on (within a reasonable time). Do you mean that the SatMap doesn't do this at the moment?

> But why should n't they charge for a firmware update that gives extra functionality

Most manufacturers offer firmware upgrades/bugfixes for free.  To me, it sounds like the lack of satellite data storage was a bug, which required fixing.

> when they are unable (no idea why) to provide it as a download.

Which brings me to the next point: in this day and age, to provide a product of this nature that cannot support firmware upgrades via USB is pretty poor, IMHO.

remebering where you last were as a chargeable item is just taking the piss. the unit remembers your last position so why doesn't it, like any other gps unit out there, remember the satellites info too? also, as well as being charged for the privilege it will also only remember the info for 8 hours!! why not longer?

i like the unit a lot but it is immensely frustrating to wait at least 6-8 mins (record so far has been 37mins) for it to get a satellite fix. three other garmin gps units are up and running within two mins.

as far as i can tell if you send in a couple cards for the maps to be put on one card or you wish to buy 25k and 50k mapping on a new card this "remember where i am" so called upgrade isn't free. even more reason to be hacked off with it.

if it was £4.99 i wouldn't be quite so vitriolic about it because it is entirely their problem. but £9.99!

yep, it costs them money to buy cards. no way can they justify £9.99. it would have been cheaper if the progamming was correct in the first place. not to mention the bad will of pissing off, again, their customers who have parted with a LOT of dosh to get this unit and maps.

> also, as well as being charged for the privilege it will also only remember the info for 8 hours!! why not longer?

That's a pragmatic issue, and I'd imagine is down to the validity period of this data.  When they say it keeps the data for 8 hours, I think what they mean is that the data will remain valid for 8 hours, after which it's useless*.  I doubt they delete the data after 8 hours, just that when the device is turned on again, it decides there's no point looking at that obsolete data.

*A limitation of GPS, I'm afraid; ephemeris data is valid for four hours.

The almanac is used to tell the receiver what satellites to look for in the sky; it allows the unit to predict the satellite orbits, and thus which satellites are overhead, provided the unit has a reasonably accurate clock.

As wiki says "In older hardware, lack of an almanac in a new receiver would cause long delays before providing a valid position, because the search for each satellite was a slow process."  It takes 12.5 minutes to receive the almanac from a single satellite, although it may be possible for a receiver to piece together a composite almanac from a number of satellites (each of which transmits the almanac for the entire constellation), and thus acquire the almanac quicker if it's lucky enough to find more than one satellite by chance, picking either a random selection of satellites, or using the last list it was looking at.

> i like the unit a lot but it is immensely frustrating to wait at least 6-8 mins (record so far has been 37mins) for it to get a satellite fix

Sounds like the 37 minutes was "none of the satellites I was looking at happened to be in the sky, so I didn't find any for quite some time".

One other feature that a receiver can use is to search through the entire constellation list, rather than looking for a subset of satellites.  That's why it's sometimes useful to have receivers with as many channels as there are satellites, so each can be looking for one satellite in the constellation, wherever it might be.  When the channels start receiving data, they can be flagged as active.

thanks for the info capt. most useful. curiously the 37 mins was at the same place the unit was switched off the previous time a week before - boxhill & westhumble station to be precise - whereas it usually takes 6-8mins. i've no idea (nothing new there) what's going on.

interesting about the time validity of data. so the easy comparison is why does my garmin gps get a position fix quicker than the satmap - and the gps with an "old" chip set.

i agree james. it's a great unit. mine's been upgraded to v 1.4 all round with the much looked forward to improvements. the where you are now being at the bottom of the screen is excellent.

currently, if you switch the unit off it loses all satellite info so that when you switch it on again it starts from scratch - in other words it's pretty useless if you just want to take a peek at where you are from time to time. the £9.99 bit is for the unit to "hibernate" up to 8 hours so that you can switch it off and when you switch it back on again it will more or less instantly show your position from saved satellite data; this feature pushes the battery life up considerably whcih is very handy indeed for multi-day trips or just for when you don't need it on all the time.

in other gps parlance you are paying for the ability of the unit to get a warm fix.

for some reason this can only be done via an sd card. and no mention of this being free if you buy new maps or get your maps organised. after all, the sd card is only the delivery system for the update.

Right Parky Again, now i understand why people are getting pissed with it , that bit slipped me by. 

I did pay for the very expensive and over priced  battery pack which however is very good and  has never gone flat on me yet and usually last for 2 to 3 good day walks. So the hibernation function for me wouldn't be necessary. The world basemap is of interest but £40 plus for sending back to be done , although as the mrs cant think what to buy me for Christmas, this may be a dood pressie

cheers

James

> his aerial needs re-tuning

Explain this aerial re-tuning to me...

Surely they're using a standard patch antenna that should require no tuning?  I can't recall seeing a GPS module that had any tunable RF elements (at least none that required physical manipulation of the device).