CD70 Navi GPS Error

[pshankland]

Hi all,

Fitted a a CD70 Navi along with paired screen into my pre-face lifted Vectra C SRi (full canbus). Everything is working well except for the GPS as keep getting the error I have attached to this post.

I have tried connecting the aerial from the original car which had the GPS receiver built in as well as a seperate Fakra one (listed below) but the error never goes, even after 20mins +

http://www.ebay.co.uk/itm/2510386968...84.m1497.l2649

Anyone got any ideas what this might be?

Thanks.

Pete.

[paulhb]

Sorry mate seen this recently but it's not seeing the satellites did you place the eBay aerial outside in case your glass is blocking the signal

[lutonmatt]

and did you take a drive about

[DAVIDD88]

Is all the plugs connected on back of cd70,

[Aidi]

If you have just installed the unit it could be a case of the unit needing to download the satellite database - called the ephemeris. Basically its a reference for the GPS to look at and then know where to look for the satellites in the sky based on your geographic location. If the unit has been dorment a while prior to purchase, or you are now a fair distance from where it was last used then it will need to update.

This can take a fair amount of time which is why you are seeing your unit not connecting. The best thing to try is find a location which has a clear view of the sky and as much of the horizon as possible. It can take a while for the info to be downloaded, but as rule of thumb, about 1/2 hour should be fine. I had to do this on my unit when i first bought it after having the same problem as you fella, since then its connected almost instantly.

The same happend with a telescope that i bought with a GPS. No fixes until it had sat outside for about 20mins


Just out of intereset, for those who read this post and have CD70 already - have you experienced any problems with your satnav not working correctly recently?

Reason i ask is that i have had mine installed for near on 2 years now, and the last time i used my car ( a week or so ago) on two seperate days it would connect and give me a route, then about 1/2 hour to an hour later it would stop working.

Kinda strange i thought considering it had worked flawlessly with getting a fix and keeping the route live from start until finish.

It could just be coinciedence that this has happened to me, or are there others with known working satnav's all of a sudden having problems?

[paulhb]

I have just installed one with a fellow member and it came from the North West and was installed in the South East. Once the aerial was connected physically to the HU the Sat Nav popped up within a couple of mnutes, so not sure why it would need 1/2 hour of staring at the sky to learn up.
Folk buy Sat Navs all the time from Halfords and the like and they come out of their boxes popped in a car from the factory and bingo they work, not doubting you Aidi but its the first I've heard of this
That symbol means its not picking up them pesky satellites

[Ben50n]

What disk are you using? Is it a proper one or an Ebay one?

[Aidi]

I would agree Paul, i have bought two TomTom's from halfords over the years and both worked within mins of taking out of the box.

I have experienced it twice on two seperate devices (car and telescope) and more recently on a Garmin GPS Running device (because i was lazy and didint use it during the winter!) and seen others rectify their problems when getting the same... This might explain things a bit more in detail - oh and i made a mistake, its not the ephemeris its the almanac which i should have refered to.

Its a bit of a catch 22 with a new unit and the symbol crossed out - Is it not finding the sats because it does not know where to look, or because the antenna is not working correctly to collect the data?

Almanac and Ephemeris Data as used by GPS receivers


The satellites broadcast two types of data, Almanac and
Ephemeris. Almanac data is course orbital parameters for all
SVs. Each SV broadcasts Almanac data for ALL SVs. This Almanac
data is not very precise and is considered valid for up to
several months. Ephemeris data by comparison is very precise
orbital and clock correction for each SV and is necessary for
precise positioning. EACH SV broadcasts ONLY its own Ephemeris
data. This data is only considered valid for about 30 minutes.
The Ephemeris data is broadcast by each SV every 30 seconds.

When the GPS is initially turned on after being off for more than
30 minutes, it "looks" for SVs based on where it is based on the
almanac and current time. With this information, appropriate
SVs can be selected for initial search.

When the GPS receiver initially locks onto a SV, the Garmin
display then shows "hollow" signal strength bars. At this time,
the Ephemeris data has yet to be completely collected. Once the
ephemeris data is collected from EACH SV in turn, the associated
signal strength bar will turn "solid" black and then the data
from that SV is considered valid for navigation.

If power is cycled on a GPS unit, and when turned back on, the
Ephemeris data is less than 30 minutes old, lock-on will be very
quick since the GPS does not have to collect new Ephemeris data.
This is called a "warm" start.

If it is later than 30 minutes, this is considered a "cold"
start and all Ephemeris data will have to be recollected.

If the GPS has moved more than a few hundred miles or accurate
time is lost, the Almanac data will be invalid and if you are
far enough off, none of the SVs that the Almanac thinks should
be overhead will be there. In such case, the GPS will have to
"sky search" or be reinitialized so it can download a new Almanac
and start over.

[pshankland]

Spent a while on this today...

1) Took the car on a 30mins drive with the Takra GPS receiver installed in the centre dash speaker well - No GPS
2) Removed the Takra and placed on the roof. Took for another 30min drive - No GPS
3) Left the Takra on the roof and left the car parked on the drive but with the CD70 switch on for 30mins - No GPS
4) Removed the Takra and attached the factory fit GPS receiver (the one built into the aerial). Quick connection for testing so left the GPS receiver on the dash for 30mins while car parked but with the CD70 switched on - No GPS

So, everything I have tried so far has failed but have one option of leaving the car parked with the CD70 on and the factory GPS receiver on the roof. I'll try this tomorrow and see what happens - fingers crossed.

The only thing I have noticed is that there are some pin differences between the removed CD30 and CD70 - are these important to this issue as would assume the No GPS error should only be down to the GPS receiver.

Would appreciate ANY help

Pete.

[LeeU]

OK, the extra pins on a CD70 when compared to a CD30 mean absolutely nothing, if the CD70 isn't working with either the Fakra or factory aerial then I would suggest that part of the CD70 naffed.
Sorry.