Possible GPS Signal Fault

rxj · 25-09-2019, 08:23 PM

Hi Everyone,

Since I updated Sync 3 v3 to build 18093 (I know this is an old build) the GPS has not been working properly it only works on some days, when driving from home to the CBD (work) and return, which is approximately a 60km round trip. If I perform a master reset the issue appears to go away for a day or two before the problem returns.

It may be a coincidence as I didn’t think the core Sync 3 software had any bearing on whether you have satnav or not.

The 2018 MD Mondeo went in for the 15K service today and I showed the service consultant that I had no GPS, the dealer is located on the way to work.

When I picked up the car today I did receive the latest map update for AU which was good and the GPS seems to be okay for now. However, what was bizarre was the explanation from their “tech manager” about this possible GPS signal fault. I explained that sometimes it tracks okay along the roads I’m travelling, other days it is all over the place and cannot track to anything even when in the CBD.

The dealer couldn’t find any faults when they checked the GPS as I was told it was connected to seven satellites while in for service. I explained that I drive to work and back each day on the same roads, he said the satellite moves each day so it may not be picking up the signal. I mentioned that if I use google maps or apple maps at the time there are no issues. If all seven satellites have moved so much wouldn’t all GPS devices be impacted...not just mine. No answer.

I suggested whether there could be an intermittent fault with the APIM module, but I was told there were no issues today so it cannot be the issue. Why do some dealers treat customers like fools...they just don’t like customers challenging there thinking.

Anyway, has anyone else had similar issues with their GPS signal?

Thanks

rxj

AlanD · 30-09-2019, 04:46 PM

Hi RXJ,

I see no one has responded to your post, so I'll offer a comment or two.

1. You dealer might be more on the ball than you believe. GPS satellites have a period of 2 orbits per day - they are not synchronous - and so they move relative to a fixed point on the ground. When they drop to low angles the signal strength, which is quite small to begin with, will fall. Ordinarily this isn't a problem since usually there will be reception from enough sources to maintain a good positional fix - but you might get an occasional drop out if the GPS receiver can't "See" the minimum number required.

2. Paradoxically CBD areas are quite "poor" reception regions because of the tall buildings (usually full of reinforced concrete) preventing good reception from satellites that could be close to overhead but are shielded by buildings' structure. In this event the receiver can drop into "dead reckoning" mode (like going through a tunnel) until enough satellites have come into view. Dead reckoning can be confused in CBD areas because there is no guarantee you are going to keep going straight ahead. With a tunnel there is an entrance and a exit and the software is usually good enough, with input from the car's speed data to get you to the exit at a time when satellites get reacquired. So no apparent drop out occurs.

You do not say if the fault is a) complete shutdown (I have had this happen once and was blind until the system rebooted) or b) telling you that you are located where you know you are not ( also had this happen once in Wyoming where the GPS was saying we were about 400m north of the highway we were travelling along and wanted me to turn right to reacquire the highway).

Either way, I regard the in car system as being less accurate than my trusty TomTom unit ( which has the advantage of a speed readout that is rather more accurate than the car's speedometer)

Let us know how you get on

Cheers

rxj · 24-10-2019, 08:45 PM

Quote:

Originally Posted by AlanD

Hi RXJ,

I see no one has responded to your post, so I'll offer a comment or two.

1. You dealer might be more on the ball than you believe. GPS satellites have a period of 2 orbits per day - they are not synchronous - and so they move relative to a fixed point on the ground. When they drop to low angles the signal strength, which is quite small to begin with, will fall. Ordinarily this isn't a problem since usually there will be reception from enough sources to maintain a good positional fix - but you might get an occasional drop out if the GPS receiver can't "See" the minimum number required.

2. Paradoxically CBD areas are quite "poor" reception regions because of the tall buildings (usually full of reinforced concrete) preventing good reception from satellites that could be close to overhead but are shielded by buildings' structure. In this event the receiver can drop into "dead reckoning" mode (like going through a tunnel) until enough satellites have come into view. Dead reckoning can be confused in CBD areas because there is no guarantee you are going to keep going straight ahead. With a tunnel there is an entrance and a exit and the software is usually good enough, with input from the car's speed data to get you to the exit at a time when satellites get reacquired. So no apparent drop out occurs.

You do not say if the fault is a) complete shutdown (I have had this happen once and was blind until the system rebooted) or b) telling you that you are located where you know you are not ( also had this happen once in Wyoming where the GPS was saying we were about 400m north of the highway we were travelling along and wanted me to turn right to reacquire the highway).

Either way, I regard the in car system as being less accurate than my trusty TomTom unit ( which has the advantage of a speed readout that is rather more accurate than the car's speedometer)

Let us know how you get on

Cheers

Hi AlanD,

Thank you for your feedback.

I found that after 10 business days driving to work in the morning I failed to receive a GPS signal except on one day. However, travelling home from the CBD each day there was no issues with the GPS signal and worked as expected.

Today it failed to receive the GPS signal on the way to work as per previous days so after a master reset, while sitting in traffic it picked up the GPS signal. The GPS signal worked as expected on the way home from the CBD as per previous days.

Further testing needs to occur, so I will turn on the testing mode on the sync 3.0 console tomorrow to see if picks up any faults.

Thanks,

rxj

AlanD · 26-10-2019, 07:25 AM

Hi again RXJ,

Seems to be either an intermittent fault that might be system voltage dependent or a location problem that is only there at certain times of day.

You do not comment as to whether the GPS is active when you begin using the car in the morning and then drops out at some point along your route, but doesn't do the same on your return trip later in the day.

So I'll ask some questions:

1. In the morning is the GPS inactive from the time of engine start?
2. At what time in the morning do you leave for work?
3. At what time in the afternoon do you leave for home?
4. On the day that the GPS did work in the morning, did the car get used in the evening and if it did was it a long(ish) trip? Arriving at home at what time?
5. What time of day do you leave for work?
6. Are we talking about the MC? MDs have been on the market since 2015 (I think) so your battery will now be getting on for 4 or more years of age unless it has been replaced. Am I correct in this assumption?
7. Is the car garaged at home inside or out in the weather?

You might get a feel for where I am going with these questions.

Cheers

rxj · 08-11-2019, 09:46 PM

Quote:

Originally Posted by AlanD

Hi again RXJ,

Seems to be either an intermittent fault that might be system voltage dependent or a location problem that is only there at certain times of day.

You do not comment as to whether the GPS is active when you begin using the car in the morning and then drops out at some point along your route, but doesn't do the same on your return trip later in the day.

So I'll ask some questions:

1. In the morning is the GPS inactive from the time of engine start?
2. At what time in the morning do you leave for work?
3. At what time in the afternoon do you leave for home?
4. On the day that the GPS did work in the morning, did the car get used in the evening and if it did was it a long(ish) trip? Arriving at home at what time?
5. What time of day do you leave for work?
6. Are we talking about the MC? MDs have been on the market since 2015 (I think) so your battery will now be getting on for 4 or more years of age unless it has been replaced. Am I correct in this assumption?
7. Is the car garaged at home inside or out in the weather?

You might get a feel for where I am going with these questions.

Cheers

Hi Alan,

Thank you for your feedback and further questions.

Answers to your questions.

1. It is not inactive when I start, it fails after about 2 minutes
2. Between 6.30am and 7.15am
3. Between 6.00pm and 6.30pm
4. No different to any other day. Only use the car to go to work and back. Not used for any other purposes. I have other cars.
5. Morning only
6. MD - 12 months old
7. Garaged never outside

However, I have performed another master rest since this post and so far no further issues.

Cheers,

rxj