New user having bother

[Buffy Beagle]

Hello, this is Hugh (the navigator's driver!)



We got TTN2 a few days ago and have only been out driving once since and failed to get any satellite signals at all (from our Socket/Emtac Bluetooth on our iPaq 3970) in a round trip of 10 miles. Since then, while we've been sitting at home, trying to test out what is happening, the satellite fixes have come and gone erratically.



So ... we've been re-reading the above discussion with great interest.



One basic question that we have not seen answered is: does the Pocket PC communicate any information or instructions to the GPS receiver. We had assumed that it did not and that the information flow was entirely one way ... from the GPS receiver to the PC. However, 2 things suggest that this may not be the case. The first thing is that the TTN2 manual (which is much clearer than the one with TTN1) says the "Reset GPS for this location" menu option will help the GPS receiver find out where it is if it has moved to a new place since it was turned off. The second thing is that simply turning TTN2 on sometimes seems to cause the green light on the GPS receiver to stop flashing (which we think means that the GPS has lost its satellite fix.).



If TTN does transmit to the GPS, what does it transmit and when?

[Dave]

Hugh, data is primarily one way, you're correct with this. The Reset option basically allows you to give the receiver a slap around the head when it's doing something wrong. In most cases, what it should do, eg if your last fix was in Winchester, and you're now in New York, is perform a factory reset of the receiver. The reason for this, is there's two sets of data, Almanac and Ephemeris. The Ephemeris is using data for your last known location, and you're trying to receive data based on this information and perform calculations. When a factory reset is performed, or even a cold reset, you are clearing this data down and requesting a new download (takes 30 seconds+ for Ephemeris). Alamanac data is a coarse set of data showing roughly where satellites are (not actual positions) and is current for 2-3 months.



Now, the way TTN2 does it I believe, because I've tested this myself, is that it knows what your last known co-ordinates were when you last used TTN2, and it will use this to position you to the map.



Now say for the sake, you last used TTN2 when you ended up in Winchester, but you're now in London, and you switch the receiver on and TTN2. It's having a problem gaining a fix because you're in an underground car park, so you say use last known position. What will happen is suddenly the map will show you in Winchester, and you'll start getting some very erratic moving across streets, into fields and lakes, until you receive a 3D fix in which case after about another 30 seconds, it should show you a proper map of where you are. This feature, the way TomTom use it is good, from the point of view that if the last known location is where you are going to set off from, then in theory a 2D fix will suffice.



The Pocket PC shouldn't interfere, it has to do a handshake to the BT GPS, eg opening the port for receiving data, as you're using a serial connection, but that's all it does, unless you or the program instructs it to program the GPS, then there should be very little transmissions to the receiver.



TTFF's can be a fine art, I've been doing extensive testing of three new receivers I'm reviewing over this holiday weekend, testing them in the morning, which is what I usually do, has given me some very sporadic results, so I've had to move my testing to the afternoon to test these. Probably an illegal alien nearby!

[MikeB]

TTN only reads from the GPS the "usual" mode of operation is NMEA (original GPS protocol to allow the GPS to talk to other devices like PDA, AutoPilot etc.). The NMEA protocol does not have two way communication. When TTN asks for your location it is to help locate the satellites faster. This is typically required when you have moved more than a hundred miles with the GPS switched off.
_________________
Mike Barrett

[Buffy Beagle]

Thanks, Dave and Mike for your prompt replies. I'm still trying to digest them, but I have an immediate specific question:



If there is no communication from TomTom to the GPS, what do you mean, Mike, when you refer to helping TomTom locate satellites faster. Surely, it is not TomTom's job to locate satellites? Surely it is the GPS that does the locating of satellites and what TomTom does is read messages from the GPS which either include the current latitude/longitude coordinates or they don't?

[Buffy Beagle]

As we've said in other threads we've now had the chance to put TTN2 to proper use and it has behaved well, so we no longer have concerns about satellite fixes.



Thanks again for your help.



Hugh

[Skeletal]

I've not been "satnaving" for a while, but thought I'd just drop into the forum (I've been spending hours sorting new problems upgrading a motherboard/processor/hard disc on my computer...why don't I give up all technology and live on top of a pole in the middle of a desert?!).



I'm pleased this thread has been of use to others and, more or less, the times I've used the satnav stuff it now seems OK.



But, to tell you yet another story (!), when I came downstairs the other day, I could hear a voice comming from one of the rooms. As it was female (and the wife was upstairs) I though my luck was in. However, my excitment was quickly over when I discovered the iPaq had turned itself on, TTN2 had started in the "demo" mode and was happily driving and talking to itself!



I think it was because I had put a reminder into the Outlook calender, this turned on the iPaq (I didn't know it did this) and somehow, even though I absolutley, without doubt, shut down TT the previous day, it got going by itself.



This is my continuing complaint. The iPaq does crash a lot (in odd ways) and it is related sometimes to TTN2. It is not unusual for TTN2 not to start, but to say "can't find maps, reinstall software" (can't remember exact message). If this appears I have to hard reset the iPaq, in some cases 2 or 3 times. Still not got to the bottom of that, but at least I can usually make things work now.



Skeletal

[Dave]

Yep I've seen that problem of the talking woman in the other room, this is one of the main reasons why I religiously exit TTN each time, because TTN will also stop the Pocket PC going to sleep which means it's more likely to keep it awake and drain your battery.



I'm actually testing another complete in-car system at the moment (not based on Pocket PC's), and I've had this crash several times already which has required a complete powerdown of the device, so it's not just Pocket PC's that have crashes (unfortunately!).

[Skeletal]

I’ve now done a load more tests this lunch time:



Socket on bench: about 4 satellites

Back of Socket on palm of hand, hand open: 4 moving to 5

Cup hand completely around Socket: 0

Hold antenna outer ring: 3 moving to 4

Poke wire into antenna centre and hold: 4

Poke wire into antenna and hold, and other hand over Socket: 0

Front of Socket on palm of hand: 2 moving to 1

Front of Socket on bench: 4 moving to 5

Back of Socket on bench, metal tray resting on top of Socket: 1 moving to 0 (no surprises here!)

Back of Socket on metal tray, metal tray on bench: 4

Back of Socket on bench, Bluetooth on Ipaq changed from low to high signal transmission: 4



Thus, putting the Socket “face down” on your hand cuts down the satellites, putting it “back side down” slightly improves reception (so this actually, is not that different from what you found Mike), wrapping it in your hand kills everything. Holding the antenna socket is no problem. Interference from the Bluetooth system does not seem to be a problem either.



What is the point? Well, I for one, as a total beginner at GPS, get all my goodies, and hold them as I play. I turn on the GPS indoors, then carry it to my car, expecting to get a lock on the way (I still need to prove you can’t get a lock if you’re moving!). Now I know it won’t work “wrapped” in my hand, I know what to do (also, when I was holding it over Windermere it was tightly “wrapped” funnily enough!).



“Would you hold a Navman Jacket or a Garmin GPS by the antenna?” I wouldn’t hold anything by an antenna if I could identify it as such. I presume you don’t hold a mobile phone in your hand???!!!



As regards TomTom, there is no doubt it crashes, but it’s hard to figure cause and effect. I think bonding helps, as does shutting it down before turning off the iPaq. I also think if the Socket is “half” locked when you turn on TomTom, you get a crash. In my earlier struggles, I seemed to think that ticking the box in the GPS bit of TomTom made things work, however, I now think that all I did was being influenced by my holding the Socket (or not) i.e. I may have put the Socket down while I fiddled with the iPaq; it would have then sprung to life, not because of my fiddling as I thought, but because I wasn’t holding the Socket.



I never thought it would be this difficult!!



Thinks he’s cracked it Skeletal

[aero]

Quote: Originally posted by Skeletal on 03 April 2003

---

....where did you get all the info from??!!!

---

Uh....the above post on how to bond came straight out of the instruction manual !!



Chortle



Skeletal, I put the ? in because I wasn't sure what the PIN code for the Emtac was ('cos I haven't got mine yet). It asks you to enter the PIN code the moment you tap Create Bond With This Device

[aero]

Good Luck!



(To be fair though Skeletal, the instructions to Create a Bond came in a separate 'Special Features' booklet with your ipaq. It's one of those booklets no-one reads!)

[SJTaylor]

You may have problems picking up a signal in your car if you have an athermic windscreen. (Mainly crappy French cars). In such a case just stick the GPS on the parcel shelf.



I got a Socket branded device which didn't come with manuals or Crux View but you can get both from the Emtac website.

[Skeletal]

Hi Guys and Gals



I wonder if any of you SATNAV gurus can answer a few questions for me??



I know nothing about PDAs, Bluetooth or GPS but have just bought a Compaq 3970, Socket Bluetooth GPS receiver and TomTom navigation software.



I don't think the information given with any of this stuff is very clear and had problems setting it up. However, I am now at the point where it works sometimes and not others. When it does work it is brilliant, and will say “you have reached your destination” exactly where I should be, BUT...



1. I turn on the GPS, then turn on the Compaq. The Compaq complains it will “set a route when it has clear GPS info” (or similar). It then sits there and does nothing. Looking at the GPS status panel, (signal strength screen) I may have 5 or 6 satellites detected. Going to the GPS screen (the one with a map of the world) I have found I can sometime make things happen if I press the tick box at the top. However, doing this today and it all crashed and I had to do a hard reset. Staring from scratch and I got it to work again.



2. Yesterday, something similar, but as I drove around, there were no voice messages even though all the volume controls were “on” etc. Doing a hard reset and it all worked.



3. Yesterday, there was one point where the directions were totally incorrect and it seemed “lost”. A mile or so later and it was fine again (although had I have not known where I was I would have been very lost by then!).



4. Last Friday was odd. At lunch time the GPS receiver would not work at all. The green LED that says it has a satellite lock did not come on, no matter where I went. After about an hour, it suddenly came on and all was well.



5. Looking carefully at the GPS status panel, (signal strength screen) I note that the satellite detection is incredibly sensitive. Moving the receiver as little as 6 inches can make the difference between 6 satellites and none! Also, I assume that the height of the bars indicates signal strength for each satellite and if they are grey, they are too weak, turning red means OK.



6. There is one spot in my house where I get all 6 (by a window). Obviously, moving in the middle of the house drops to 1 or 2. Moving outside can still result in 0 to 6 depending on where I stand. Doing the same in the car has a similar effect. I normally have the receiver in my shirt pocket. Moving it close to the windscreen can result in the signal going up OR down. The positioning is totally random.



7. Finally, on the GPS screen (the one with the world on it) what is the meaning of the PDA symbol? The slider bar to the left puts “ZZZ” symbols on it so I guessed it is something to do with sleep. I set it so it does not have the “ZZZ” symbols. Is this correct?



8. I have read a few posts (which I only half understand at the moment) and have come across “bonding BTGPS using 0183 as passkey”. What on earth is that about? Will it help?



Thus, in conclusion am I correct in saying:



PDAs crash as badly as all Windows based computers (at least a crash a day so far!).

Satellite receivers only work reliably if they have a 100 foot antenna and remain totally stationary.

The TomTom software sulks and won’t plot your route even when it has perfect satellite info.

The satellites are all turned off at Friday lunch times for an hour.



Sorry for the long post, if nothing else, I hope it provides amusement for all readers!



Skeletal

[MikeB]

Skeletal,



If you switch your system on and the GPS thinks you are in the middle of a field it will wait until you are on a road before it will plot a route for you. This will often happen if you are in a new area which is not on the TomTom maps. As soon as you reach a road it will start planning.



If your BT GPS Green light is not coming on at all there is a problem with the unit. It should be on constantly when you dont have a satellite fix and flashing when you do.



I would expect that you wouldnt get a good fix inside your house, but at a window should be fine. GPS uses weak radio signals which can be blocked by various obstructions.



You are correct in your assumptions about the GPS Status screen. Red bars represent sats that are in use, and the Grey ones are those in view but not fixed.



Does your car have a coated windscreen? These can seriously affect the reception of signals. Try placing the GPS on the rear parcel shelf and see if that improves the signal.



Bonding or Pairing the PDA to the GPS means that they know about each other and the services that are provided. This helps when connecting the two devices.


_________________
Mike Barrett

[Skeletal]

Hi Mike,



Thanks for trying to help. I certainly didn’t know about being near a road. Of course “near” may vary with signal strengths and which satellite the GPS has locked on to. I think one of my failures to plot a route was when I was in my back garden, which is half way between two roads.



I played with the system for ages (again) yesterday and it happily plotted routes. It was picking up 6 satellites in the middle of my house! This is part of my confusion, one second (literally!) I have 5,6,7 satellites, and then none.



The problems occur whether I am in a car or outside (2 different cars as well). By a window in the house usually is better (until yesterday!).



BUT something I am latching on to now, everything seems better behaved if I shut down TomTom BEFORE turning off the iPaq. On this note please could you (or someone) explain how I “bond” the devices. As I mentioned, I think the documentation is poor, there is no mention at all about Bluetooth, let alone bonding. I have gone through all the screens but can’t see anything obvious.



The green light is always on, or flashing, which is why I only half think it is broken (if you see what I mean!).



As I write this, I have the GPS in the same position as the “6 fix” yesterday and the green light refuses to flash! I have just started TomTom and had to go to the GPS screen to tick the box. Status shows no satellites. Moved to window and it all works (and I plotted a route). However, it is raining. I assume that wet masonry will reduce signal strength more then dry!



I am beginning to think that I have had a combination of many factors, i.e. crashing software, trying to plot a route in the garden, and finding myself in “cold spots”.



The question about the satellites being turned off was genuine. I understand that data is uploaded to them from ground stations. Don’t they have to be “off” for this to happen, or is it over very quickly?



Thanks again



Navigating to end of garden Skeletal

[SJTaylor]

1. It won't plot a route when I'm in my back garden either. You have to be near the road.



2. This happened to me once. Unfortunately, I can't remember why.



3. It happens, the system (more often the map) isn't perfect but it's better than my navigation.



4. Sounds like a dodgy unit or it wasn't charged? Green light should be continuously on when the unit is switched on and then flashing when it has a loc.



5. The satellites aren't geosynchronous and their positions move over time in relation to the earth. You will get varying signals depending on time of day and the number of satellites in view, weather, relief, buildings, signals bouncing off buildings etc.



6. As above and some cars have metallised windscreens to reflect heat, mainly crappy French ones.



7. Swithcing to ZZZZ means the PDA will power down depending on your setting. The other option allows TTN to keep it on.



8. It's a lot easier if you bond them.



Switch Bluetooth on and turn the EMTAC on. Go to the Bluetooth Manager, Tools, Paired Devices, Add, Select the Browse icon next to the devices box to search for the EMTAC. Select the EMTAC. Enter 0183 in the Passkey box. Click OK at the top right. It should then say it is pairing the devices.

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