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0 pointsasdff3y ago0 comments

I have no experience with tom tom but I was a garmin user, and I got the sense that tom toms were pretty much identical. IMO an integrated tom tom into the car, if it performs as well as the external unit, would be amazingly better than your cell phone. The biggest advantage imo is satellite coverage is much better than quality data network coverage. I'm not even talking about in the boonies. Plenty of times in the middle of LA county I am sitting there waiting on a seemingly stalled LTE connection to render a map I supposedly had already cached locally according to google maps.

0 comments

cgriswald3y ago

I have an older in-car system and my experience is the opposite.

First, the car doesn't download map data. I'm stuck with what was on the car when I bought it unless I want to pay an unreasonable amount to update it.

Second, it does download traffic data, but it's so slow that it's useless. I took its advice once and it cost me over an hour, because the alternate route had already filled up and had the disadvantage of not being a freeway.

Third, it can't navigate a path without connecting to the satellite (seemingly for traffic data, but possibly it isn't even calculating the path locally). So when I visit downtown SF, don't have up-to-date maps, and I'm inevitably behind some building blocking my southern view, it just abandons me.

krisoft3y ago

> Third, it can't navigate a path without connecting to the satellite (seemingly for traffic data, but possibly it isn't even calculating the path locally).

I’m confused by what you are saying here. In-car navigation use satelites to know where the car is. If it can’t path plan without satelite connection then that is most likely because it is waiting for a localisation fix.

Trafic information could be coming through satelite broadcast but I doubt that it does.

There is no way that a navigation tool would receive path planning through satelite. Two way communication is much more complicated than one-way reception, and there is no way it would be financially worth doing that.

pandaman3y ago

Sirius sells traffic info add-on, which is broadcast from the satellite. It is not as detailed as the data-linked apps in cars/phones and is only available for the few big metros but can get the traffic info on an older car's nav system.

cgriswald3y ago

See my response to the sibling poster: https://news.ycombinator.com/item?id=31587520

gh02t3y ago

Don't forget the best part -- if you do want to update the maps they want to charge you 300+ dollars every year!

nsonha3y ago

Is that an exorbitant amount of money for maintaining a (global?) digital map? Google messes up our sense of value with their ad money.

2 more replies

Hamuko3y ago

>First, the car doesn't download map data. I'm stuck with what was on the car when I bought it unless I want to pay an unreasonable amount to update it.

Apparently car navigation maps are a thing that you can also pirate. I think I saw a Windows tool for downloading Mercedes-Benz map updates. Never tried it though, since I was pretty content to sticking with Google Maps and a phone mount.

brnt3y ago

My car manufacturer just posts an update every year that I can tranfer myself to the SD card that it reads off. Pretty nice.

anamax3y ago

The in-car GPS systems are a disaster (because the car manufacturers see them as "cash after sale") but the separate/dedicated GPS units are pretty good.

The updates and traffic information is, or at least was, free.

chrisseaton3y ago

> Third, it can't navigate a path without connecting to the satellite

How else would it work? Just sense which way the wheels are pointing and track the speedometer?

cgriswald3y ago

I perhaps should have said find rather than navigate. I don't expect turn-by-turn navigation when it has no way of knowing where I am. I'm not talking about it directing me along a path; but about finding the path in the first place.

It should use the last known location and vector to find a route. It doesn't. My guess is that it loses the satellite, sees it again and starts recalculating, loses it, and repeats this cycle. Unless the satellite is visible for a long enough period, it never produces any path. Even an out-of-date path would be more useful than simply nothing.

mynameishere3y ago

That, of course, is called dead reckoning and some GPSes have it, but I wouldn't trust it for very long. [1] I'm not sure what cgriswald is on about. Maybe he just lives in a tunnel or some dead zone, because I've never lost satellite connections. Maybe cellphones can triangulate via cell towers? But how is he getting cell data in his tunnel?

[1] Pre-GPS systems used this https://ndrive.com/brief-history-gps-car-navigation/

1 more reply

rootusrootus3y ago

CarPlay, at least (and I kinda assume Android Auto) uses the car's built-in GPS receiver when available. Doesn't necessarily solve the non-cached maps when LTE is unavailable problem, though.

j / k navigate · click thread line to collapse

0 comments

cgriswald3y ago

I have an older in-car system and my experience is the opposite.

First, the car doesn't download map data. I'm stuck with what was on the car when I bought it unless I want to pay an unreasonable amount to update it.

krisoft3y ago

> Third, it can't navigate a path without connecting to the satellite (seemingly for traffic data, but possibly it isn't even calculating the path locally).

Trafic information could be coming through satelite broadcast but I doubt that it does.

pandaman3y ago

cgriswald3y ago

See my response to the sibling poster: https://news.ycombinator.com/item?id=31587520

gh02t3y ago

Don't forget the best part -- if you do want to update the maps they want to charge you 300+ dollars every year!

nsonha3y ago

Is that an exorbitant amount of money for maintaining a (global?) digital map? Google messes up our sense of value with their ad money.

2 more replies

Hamuko3y ago

>First, the car doesn't download map data. I'm stuck with what was on the car when I bought it unless I want to pay an unreasonable amount to update it.

brnt3y ago

My car manufacturer just posts an update every year that I can tranfer myself to the SD card that it reads off. Pretty nice.

anamax3y ago

The in-car GPS systems are a disaster (because the car manufacturers see them as "cash after sale") but the separate/dedicated GPS units are pretty good.

The updates and traffic information is, or at least was, free.

chrisseaton3y ago

> Third, it can't navigate a path without connecting to the satellite

How else would it work? Just sense which way the wheels are pointing and track the speedometer?

cgriswald3y ago

mynameishere3y ago

[1] Pre-GPS systems used this https://ndrive.com/brief-history-gps-car-navigation/

1 more reply

rootusrootus3y ago

CarPlay, at least (and I kinda assume Android Auto) uses the car's built-in GPS receiver when available. Doesn't necessarily solve the non-cached maps when LTE is unavailable problem, though.

j / k navigate · click thread line to collapse