The WondeX BT-100Y Bluetooth GPS Receiver Manufacturers Specs
The resale box for the WondeX BT-100Y Bluetooth GPS Receiver shows some nice marketing blurb.
You can only see about 12 satellites. What they meant to say is "44 channels" so that you can receive multiple signals from the same satellite, particularly in urban canyon conditions.
The operating time estimate is very optimistic, our tests with the supplied 950 mAh battery yielded a consistent operating time of 13.6 hours under permanent load.
The receiver itself is equipped with a SkyTraq Venus 521e chipset. More on that later.
The receiver uses a nice big patch antenna, not one of these miniature versions we keep seeing as of late.
The marketing blurb also states ROHS which stands for "Reduction of (use of) Hazardous Substances". To you and me this means they use a lead free solder. While this is a commendable feature it remains to be seen how well this is implemented. Lead free solder joints are known to be a tad brittle. On my review unit the battery connector (shown above) came loose and had to be resoldered.
I was a bit amused to see the word "vibration sensor" - but the actual motion sensor is not that bad, really. It looks and sounds funny (when you shake the receiver it rattles, so the sensor must be entirely mechanical) but it works flawlessly and recognizes the sligthest motion.
I am really curious to know what these four golden screws are for... Do you think they allow to set the sensitivity of the motion sensor?
Anyway, the receiver will go into light sleep after ten minutes without Bluetooth commuincations. This means the Bluetooth itself will stay on but the GPS receiver part will be switched off. If a new Bluetooth communication is established the GPS will wake up and re-acquire the satellites.
If there is no activity for half an hour the receiver will switch off completely. Whenever motion is detected (ideally the motion of your car, and not just a truck thundering by) the receiver is woken up and listening to Bluetooth communications again.
We already mentioned that the receiver will run continuously for 13.6 hours before stopping the GPS data stream. In that time the device shows very solid performance, without a single drop in reception. This is no small feat given that the test location is not exactly receiver paradise (no clear sky view, about 4 metres away horizontally from the roof window). Other devices like the new TomTom 720 fail to actually get a fix in that location.
First test run
Second test run
Low DOP values mean that the reliability of the computed location is high.
Assisted GPS means that the receiver gets some initial help to understand which satellites to expect and where to expect them in the sky. This is achieved by downloaded the so called Ephemeris table not from the satellites (like normal receivers would do) but from a secondary datasource.
A-GPS is very common in mobile phone GPS receivers (because they generally have a weak GPS that can use any and all help it can get), to my knowledge the WondeX BT-100Y Bluetooth GPS Receiver is the first standalone receiver with this feature.
In this case (remember the device has a SkyTraq chipset) the data source is the SkyTraq FTP server. It holds an Ephemeris table for the next seven days.
To download the Ephemeris to the receiver you need to have a Bluetooth enabled PC that is connected to the internet. This is quite a bit inconvenient since not all laptops come with Bluetooth built in. I would have preferred to be able to use the USB connection as an alternative.
The download program is included in the box but you can also get it from the BuyGPSNow.com support forum (I also heard that a Pocket PC version of the download program is in the works).
Once the Ephemeris has been transmitted your receiver should be getting an initial GPS fix much quicker, at least for the coming seven days. There is one scenario where this makes sense - when you are about to go on a transoceanic flight, and need to use the receiver immediately after you arrived.
Normal GPS receiver will be confused by the location change, and will re-download the Ephemeris from the satellites (this can take up to 15 minutes). The WondeX BT-100Y Bluetooth GPS Receiver will lock on to the satellites within a few seconds.
Apart from that I found the A-GPS feature too cumbersome to be of much use. I would have liked to get some visual feedback from one of the many LEDs that my receiver's Ephemeris data is about to expire. Without that I simply forgot about the updates. And the very good standard performance of the receiver also helped to forget about A-GPS.
Apart from the Ephemeris download the receiver also comes with a control program where you can set and view various aspects of the receiver. You will see a "datalog" menu item, but unfortunately this receiver does not have a datalog feature.