Instruction: Answer the given question by extracting information from the supporting document.

Input:
Question: Hi, anyone knows about the frequency of the GPS. I mean the update rate. Is it 1Hz or more?
Document: bought this because they claimed they fixed the Vista compatibility issues. They did not. Tried on XP worked, then 2 Vista laptops. Neither Vista laptop see the GPS. Has anyone gotten this to work on a Vista machine?Update, appears the program they supply to check the GPS does not work in Vista. I am using  chart plotting software and when I run that everything works fine.
I've used this while sailing, using MacENC or GPSNavX. The receiver can pick up plenty of the signals very fast, and seems to be very accurate. The update rate is at least once/second.
GPS side is quite sensitive. The set-up software for ME was difficult to install as I had to find files that the software couldn't. Uses Prolific USB conversion software which isn't the greatest. Would be nice if it used CP210X which doesn't reinstall additional com ports everytime you plug it in.Vendor was top rate and shipped quickly. The product could be improved.
And everytime you restart your computer the baud rate gets reset back to 9600. So you must manually reset the rate each time you turn on the computer.The manufacturer's forum has PAGES of customer input about having trouble using this GPS with Windows 7, but virtually nothing about problems with XP or Vista. So I suspect that the unit and driver work fine with those versions of Windows.
I did not read anything about installation except that the baud rate for the serial port (USB) needs to be set at 4800. With that setting done via settings and devices, and with Streets and Trips running (2011 version), my location was pinpointed on the map in about 5 minutes in an area that is difficult for GPS satellite reception. I do not know how the GlobalSat will behave in real use on the roads, but my initial view of the product is very positive.
I just received the BU-353 today (December 4, 2010) and loaded the Mac OS 10 drivers and software on the included CDROM. It had everything you needed for both the Macintosh and Windows machines. The drivers were identical to those available from your prolific drivers referenced elsewhere in the reviews. Set 4800 baud rate and NMEA for your data type on your Mac mapping and navigation software and be sure to select the correct comm port for the GPS receiver.
The driver software included with this GPS reciever is unstable when using Windows 7. I tried both the version on the cd-rom that came with the unit and the newer version downloaded directly from the manufacturers web site. Since the GPS data stream is serial data, the driver software is suppose to create a virtual comm port. It does that justy fine. EXCEPT GPS data is suppose to stream at 4800 baud rate. That's the industry standard. The driver ALWAYS defaults to 9600.
If I can install it and use it on the appropriate software, anyone can. Just wanted to say this is an excellent, uncomplicated GPS bit of hardware to use with your laptop on Windows 7. RECOMMENDED.
I've used this product all summer and am very pleased with it. I bought it so I could use my laptop as my navigation computer on my cabin cruiser. This GPS receiver lets me do that. I highly recommend this for anyone that wants to get a GPS location fix with their laptop/PC.
After several failed attempts at having the GPS info be consistently received by OpenCPN, we discovered that the GPS puck needs to be configured to a COM port with a dedicated 4800 baud rate and that some ports default to 9600 baud rate even if you reconfigure it to 4800.
Answer: not sure if this answers your question but I have found that, for my use, the unit will not function on anything over a 4800 Baud rate. Anything below that rate seems to work fine.