This is service.

[BruceandBobbi]

We purchased a Hillspeed GPS digital speedo 6 years ago. It sits on the dash hump directly in front of the driver. It is not the type that projects on the windscreen. Last week it couldn't lock onto the satellites.

Calling them and explaining the problem I was asked to post it including a self addressed parcel bag. Asking the cost of the repair I was told...no charge...That's 4 years out of warranty repaired free.

Can't get better than that.

https://www.bogaard.com.au/

[nj swb]

We purchased a Hillspeed GPS digital speedo 6 years ago. It sits on the dash hump directly in front of the driver. It is not the type that projects on the windscreen. Last week it couldn't lock onto the satellites.

Calling them and explaining the problem I was asked to post it including a self addressed parcel bag. Asking the cost of the repair I was told...no charge...That's 4 years out of warranty repaired free.

Can't get better than that.

https://www.bogaard.com.au/

I agree, that is awesome service.

Did you have any other GPS devices in the vehicle? A couple of weeks back I had two different GPS devices unable to find any satellites - US or Russian. I was in the middle of Adelaide suburbia, so it's not like mountains or trees were interfering. They reappeared after an hour or so, and I haven't noticed any problems since.

Either way, new device!

[Dicko1]

I agree, that is awesome service.

Did you have any other GPS devices in the vehicle? A couple of weeks back I had two different GPS devices unable to find any satellites - US or Russian. I was in the middle of Adelaide suburbia, so it's not like mountains or trees were interfering. They reappeared after an hour or so, and I haven't noticed any problems since.

Either way, new device!

My gps unit also disappears at times. Several weeks ago it took a few hours before I had signal. Who knows what happens.......Probably military involved.

[BruceandBobbi]

I agree, that is awesome service.

Did you have any other GPS devices in the vehicle? A couple of weeks back I had two different GPS devices unable to find any satellites - US or Russian. I was in the middle of Adelaide suburbia, so it's not like mountains or trees were interfering. They reappeared after an hour or so, and I haven't noticed any problems since.

Either way, new device!

Nah, no other GPS device. First start of day it worked everytime. Turn motor off at shops, servo etc, restart engine and no satellites for the rest of the day. Service dept said they were aware of the problem.

[Pushbike]

Hi, In the early days (10 years ago) of GPS the US military had the capacity to switch off functions of the satellites to decrease the accuracy of the positioning. This was implemented at times of possible or actual conflict. I think that is why the Russians developed their system. It would shift the circle of accuracy out from 100m to maybe 1km. The domestic GPS receiver may not function with a gross loss of accuracy and so "shuts" down??

Can/do they (US) still have this capability? Most certainly.
Also accuracy to less than 10m was only achievable by use of a ground reference station which provided differential positioning. I.E. a calculation from satellite data and the ground station position produced the receivers position. If ground reference stations are used for domestic GPS then it may be that it was the ground stations that shut down temporarily.
Where do the ground station signals emanate from, probably from the same source as your mobile phone signal.

[Pajshomoneroguntero]

It was called SA or Selective Authority. It degraded the signal from 30m accuracy to around 100m accuracy. It was Bill Clinton that issued the directive to turn off SA back in the nineties.

As for ground reference stations I’m only aware of the GBAS stations at Richmond(Sydney) and Melbourne (somewhere around Tullamarine) used to allow for what are called GLS approaches for aviation. It is a very similar approach to the ILS which transmits a course (localiser) and a glideslope aligned with a runway. The ILS is a radio transmission (VHF) from the ground and is very accurate, reliable and has the required integrity to allow aircraft to autoland in Melbourne’s case with a 0’ cloud ceiling and as little as 75m visibility. The GLS is only authorised to Cat1 minima which is around 200’ and 550m visibilty. Although both the ILS and GLS is presented to the pilot in a similar manner the ILS derives its navigaion solution from the ground based radio transmission whereas the GLS is still satellite based with an extra corrective input from a ground based local transmitter.

That said I’m not aware of any receivers other than those used in aviation that use the ground augmentation. Given that the US designed the system (developed in the 70’s I think) and paid for it, and that most conflicts are in the Northern Hemisphere along with the lion’s share of the world’s population the satellite spread is biased toward the top side. As a result there are periods where the GPS coverage, particularly the further South you go, gets a bit sketchy. The GPS receiver needs a satellite to be above 7degrees above the horizon and also needs at the very least (in theory) 4 satellites at any one time to calculate a position (in fact two positions but one will be out in space and so can be disregarded). The more satellites the GPS unit can track the more accurate the solution. There are times where the service is degraded simply because there are too few satellites able to be “seen” by the GPS unit. Incidentally the degradation is usually short from a few minutes to 10-15 but that is for the requirements to conduct a GPS approach where the accuracy is required in the order of 0.1nautical mile to 0.3nm. There aren’t usually any outages which prevent the unit from determining its position for enroute navigation.

In the case of the car navigator dropping out I’d check that the satellite ephemeris data is up to date. That is the receiver builds an almanac of the position of the satellites for a given time so that it knows where to “look” and which satellite to expect in that position. The data comes from the satellites themselves and if the data is out of date could result in extended time to “acquire” a position. You may have noticed your mobile phone taking longer to lock its position if you haven’t turned the location on for a while. However most units should be updating automatically when they’re in use.

It could also be that the unit’s antenna is obstructed or is just a poor antenna. Therefore may be subject to more dropouts or interference however one of the features of the GPS system is that the signal from the satellites is very hard to distinguish from ordinary background noise unless the receiver knows what to listen for (which is in the ephemeris almanac). The point is that the signals the receiver is looking for are in essence weak or quiet signals and don’t generally punch though or bend around obstructions.

[chrisall]

Anyone having / had issues with older GPS devices, may be related to the GPS rollover event

https://arstechnica.com/information-technology/2019/04/gps-rollover-event-on-april-6-could-have-some-side-effects/

[Daniel-J]

In addition to tests, you can’t understand whether such a device works well or not, even expensive. I don’t know how it technically communicates with the satellite, but maybe everything is more complicated there than it seems, so there is no guarantee that your new device will work the way you want. Always buy with a warranty.

[horrorone]

I want to open same service in the future.