Sorry, can’t help with hanyu pinyin input. But I did some “research” earlier on GPS and signal strength, acquiring a “lock”, accuracy, etc., and can at least try to shed some light on this (very simplified):
If this sentence is to be taken literally, then I think it is wrong:
If the phone has no GPS receiver built in, then it only “guesses” location based on the phone network, then yes, it’s too inaccurate to be very useful. But that has nothing to do with antenna size.
If the phone has GPS, then it can be as accurate as it gets with GPS - which is way better than what you need for useful car navigation. The antenna size still has nothing to do with that.
The antenna position, though, can be a difference. If you have a car built in GPS, I guess the antenna would be installed on the roof, outside the car body. If you have a standalone GPS, like a phone, and you only turn it on while you are in the car already, then it can have a too weak signal (for example due to metallized windshield etc.) to be very accurate, or to even find it’s position within a short time. Of course you can also get outside mounted antennas for that kind of GPS, but that’s another case…
If you are interested in a bit more details… or wonder why your GPS does not find where it is even it “sees” so many satellites… read on 
The issue here is: Especially during the first time after turning on (unless you already used the GPS within the last hours), until it achieves a “lock” on the position, any GPS system needs a pretty strong signal, to “download” some info (Ephemeris data). With this data each satellite tells where in space it is. It transmits this data again and again, and you need ~ half a minute (IIRC) of a clear, uninterrupted signal to completely receive it. Unfortunately, since the satellites move, this data is only valid for a few hours. Anyway, after the GPS has acquired this data for enough satellites (at least 4 - 3 for position and 1 for time), it can accurately find it’s position even if the signals are much weaker than necessary for this download. The more satellites the GPS can use (eg. it has their data and also has a signal from them) the more accurate your GPS gets.
This is also why sometimes your GPS “sees” 6 satellites, but still can’t figure out where it is (gets no lock).
So what you want to do, in order to have a good accuracy (having enough satellites all the time) and little time to the “lock”, is to have the GPS unit standing still and with good view of as much sky as possible. Metal, concrete, Water etc. block the satellite signals. Even your body/arm, trees, etc. block this line of sight to the satellites, while plastic and glass for example don’t. So for example what I do is to lean the GPS to my home window, turn it on, and a minute later, after I finished dressing, putting on shoes, packing, whatever, take it with me. That makes sure that (even if you turn the GPS off for less than a few hours, while going to the car for example) it already “knows” the current data for a few satellites. If it gets a signal from those satellites later on, even it’s very weak (through metallized windshield etc.) it will still get an accurate position.
Additionally, the GPS also needs some basic satellite data about all satellites (called Almanach), which takes a few minutes to download. This data is valid for a much longer time though (a few months IIRC), so as long as your GPS never completely loses power (remove battery?) you will not have to worry about this part much.
Another (newer) option is called A-GPS (Assisted GPS). Many newer phones, especially smart phones, have some kind of Internet-based assisted GPS. That means they can download the necessary satellite data from the internet instead from the satellites’ signals, and then only need a very weak signal to actually use those satellites. Another option is that some GPS can calculate new data for a few days from data they have downloaded before. Anyway, both systems mean that even in most cars you can use such a kind of handheld / phone GPS without much difference to a mounted one - plus you can take it with you hiking, sailing etc.
I never checked if it has English though, considering that I can speak Chinese. That unit is long broken though, and now, on the rare occasion, I use the Papago I have installed in my HTC phone. No English on that one, but that could be as the phone itself does not have English as an option.