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GlobalSat BU-353 S4 USB GPS receiver
Ken in Regina
GlobalSat has released an update of their popular BU-353 USB GPS receiver. The new device looks and operates just like the old one.

The only difference in appearance is the old model has "GPS" on a white translucent strip on the top and the new one has G-STAR IV on a translucent black strip on the top.

The model number is now BU-353 S4.

The S4 in the model name is an indicator of the one significant change between the old and new models. The old model has a SirfStar III GPS chip in it. The new model has a SirfStar IV GPS chip in it.

While that's the only obvious difference between the two -- operationally they appear to be identical -- it's a really big difference in performance.

Mini-CD and the receiver

I just got a new notebook computer a few days ago so I set it up on the kitchen table to test the new receiver. I downloaded and installed the driver from GlobalSat's web site because I don't have a DVD drive on the new computer. I also downloaded and installed GlobalSat's little GPSInfo test utility which is always handy for configuring and monitoring a new receiver (works with any generic NMEA device, not just GlobalSat's).

Next I downloaded and installed Franson's GPSGate Express. I find it a handy tool to use whenever I have a new GPS receiver to test. I connected the S4 to the computer about the same time as I started downloading GPSGate. By the time GPSGate was installed and running, the brand new S4 already had a location fix.

That's impressive because it was just sitting on the kitchen table beside the notebook. A brand new GPS fresh out of the box needs to do a complete cold start to figure out where it is. This can usually take quite awhile and almost always needs to be done outdoors or it will take even longer or won't happen at all.

I already had Streets & Trips installed. It had no problem finding and using the S4.

I installed Street Atlas and it also found the S4 and started using it right away.

I haven't had a chance to try it in a vehicle yet but if it works that well inside the house I have no concerns about its performance in a vehicle.

Retail box

...ken...
Ken in Regina
I've attached a screenshot comparing the performance of the S3 and S4 versions of the BU-353. I didn't have a program that would allow two instances to run with a different receiver connected to each. So the S3 is running in nRoute and the S4 is running in GPSInfo.

They both have similar satellite displays so you can see which satellites are being used and the signal strengths of them.

This is with the notebook sitting on the kitchen table and the two receivers connected to opposite sides of the computer.

As you can see, the S4 is doing much better than the S3.

It should be pointed out that even the S3 version is doing very well for being indoors.

...ken...
Attached Images
s3-vs-s4.jpg  
SpadesFlush
Ken, these are similar preliminary observations to what I am seeing.

I note that you got the GPSinfo program working. I have not. Even though the GPS is registering in Streets and Trips, GPSinfo does not detect the BU-353S4 when I try to conduct a scan. Any idea what I am doing wrong?
Marvin Hlavac
Side-by-side comparison test

In the above test, the red represents the old BU-353 S3 unit, and the blue is the new BU-353 S4.

The test was performed in downtown Toronto. The area was chosen because of its traditionally difficult environment for GPS navigation due to very tall buildings surrounding narrow streets.

Both receivers were placed on the roof of the vehicle, approximately 30 cm (1 ft) apart, and the testing of both units was performed simultaneously.

Notice that the blue line (the new S4) tracks the road more closely than the red line (the old S3). This difference can really be only observed in very difficult environments.

The new BU-353 S4 had a fix on one or two more satellites during the test than the S3 version.

---

The old version has received very positive feedback from many users over the past few years, some of which can be read here: http://www.laptopgpsworld.com/4800-globalsat-bu-353-usb-gps-receiver

The new version of the receiver works just like the old version, and it even adds a bit more precision when used while navigating in difficult environments. This may be partly due to the improved sensitivity of the SS4 chip, -163dBm, versus the SS3, -159dBm.

Specifications:
Electrical Characteristics (Receiver)
GPS Chipset : SiRF STAR IV GSD4e
Frequency : L1, 1575.42 MHZ
C/A Code : 1.023 MHz chip rate
Channels : 48
Sensitivity : -163dBm

Accuracy
Position Horizontal : <2.5m 2D RMS SBAS Enable

Velocity : 0.1m/sec 95% (SA off),
Time : 1 micro-second synchronized to GPS time
WAAS : Enabled for North America product s (USGlobalSat, Inc)

Datum
Datum : WGS-84


Acquisition Rate
Hot start : 8 sec., average

Warm start : 35 sec., average
Cold start : 35 sec., average
Reacquisition : 0.1 sec. average

Protocol
GPS Protocol Default :

NMEA 0183 (Secondary: SiRF binary)
SiRF binary >> position, velocity, altitude, status and control
NMEA 0183 MEA0183 V3.0 protocol, and supports

GPS Output Data : command GGA, GSA, GSV, RMC, VTG, GLL v2.2 (VTG and GLL are optional)

GPS transfer rate : Software command setting (Default : 4800,n,8,1 for NMEA )

Dynamic Condition
Acceleration : Limit Less than 4g

Altitude Limit : 18,000 meters (60,000 feet) max.
Velocity Limit : 515 meters/sec. (1,000 knots) max.
Jerk Limit : 20 m/sec**3

Temperature
Operating : -40~ 80C

Storage : -40~ 85C
Humidity : Up to 95% non-condensing

Power
Voltage : 5V 5%

Current : 60mA typical

Physical Characteristics
Dimension : 2.32" x 1.65" x 0.82" (59mm x 47mm x 21mm)

USB Cable Length : 60" (152 cm)

Low Noise Amp
Amplifier Gain w/out cable : 27 dB Typical

Filtering : -25dB (+100 MHz)
Output VSWR : 2.0 Max.
Voltage : DC 3 ~ 5.0V
Current : 15mA max @ 5VDC

Several users of the new S4 version of this unit have commented on the faster start up time. This may be due to the following new implementation:
With the SiRF CGEE (Client Generated Extended Ephemeris) technology, has the capability of predicting satellite positions for up to 3 days in advance, and will deliver a CGEE-start time of less than 15 seconds under most conditions without any network assistance. The BU-353-S4's MicroPower mode allows the receiver to stay in a hot start-like condition almost continuously while consuming very little power.
GoneNomad
Anyone know if the S4 chipset is intrinsically more expensive than the older S3 was when it was new?

Or is the nearly double price for the BU-353S4 vs. the older BU-353S3 just due to the older model now being a deeply discounted end of life product?

BU-353 S3 $28.95
BU-353 S4 $56.95
Marvin Hlavac
First SiRFstar III based GPS receivers started to ship in 2005 (the GlobalSat 353 was one of the very first ones), so my guess is that the SiRF4 chip itself is unlikely more expensive now than the SiRF3 was years ago. If anything, it is likely less expensive (again, only a guess). So we are just seeing discounted price of the old stock, and a higher price of a brand new product. Those who cannot wait for the latest and greatest will pay a price premium. Those who are patient to wait a few months for the price to drop will save a bit.

[EDIT] I just found some historical info from December of 2007. At that time the old S3 version sold for Regular price: $79.99 Sale price: $45.99
Ken in Regina
I note that you got the GPSinfo program working. I have not. Even though the GPS is registering in Streets and Trips, GPSinfo does not detect the BU-353S4 when I try to conduct a scan. Any idea what I am doing wrong?
Mine just worked. I didn't even have to tell it to scan. It already had the correct settings selected so I just had to poke the "Start GPS" button and the sentences started to scroll.

Oh..... memory is starting to trickle back.... I first tried to download GPSInfo from their website when I downloaded the drivers (no DVD drive on the notebook). But the file seemed to be broken. The drivers worked fine but the GPSInfo download was really short and when I tried to open it it tossed an error that it was an invalid file. I tried downloading it three times with the same results.

So I broke down and dug out my portable DVD drive and installed GPSInfo from the mini CD that came with the device. Installation was clean and it ran first try as described above.

...ken...
SpadesFlush
Thanks, Ken. I have tried on my stationary PC both the GPSinfo.exe file that came on the CD and the downloaded one with the same result: the app runs but scans do not reveal any port with a GPS on it. I tried it on my laptop, PC, and UMPC all with the same (non-)result.

However, this is a trivial inconvenience inasmuch as BU-353-S4 works just fine with S&T on all three devices.
mihermano
I've attached a screenshot comparing the performance of the S3 and S4 versions of the BU-353. I didn't have a program that would allow two instances to run with a different receiver connected to each. So the S3 is running in nRoute and the S4 is running in GPSInfo.

They both have similar satellite displays so you can see which satellites are being used and the signal strengths of them.

This is with the notebook sitting on the kitchen table and the two receivers connected to opposite sides of the computer.

As you can see, the S4 is doing much better than the S3.

It should be pointed out that even the S3 version is doing very well for being indoors.

...ken...
Hi. Am I seeing those images correctly? Does the S4 put you in the middle of the northern Pacific?
tcassidy
That is a representation of the satellite locations! Last time I looked, Regina SK wasn't in the Pacific.

Terry
Ken in Regina
Hi. Am I seeing those images correctly? Does the S4 put you in the middle of the northern Pacific?
Good one, mate!! Terry is right.

It doesn't get much drier in Canada than here in the middle of the Canadian Prairies.

..ken...
mihermano
... but, if the second ring represents the horizon and the centre is your current position?? I'll make sure to check the coords next time. Cheers.
tcassidy
My S4 arrived today so I put it to the test against a BU-353 (S3) on a computer running Win 7 64. A couple of things I noted;

1)You don't need the CD as the appropriate drivers will be downloaded from Windows.
2)The copy of GPS Info on my CD is old and won't work with Win 7 64. It can't find any COM ports at all.

I downloaded the version at GlobalSat support and it worked great.

http://www.usglobalsat.com/s-24-support-drivers.aspx#A

The S4 was considerably better than the S3 in the location I tested. I also tried the Cold Start button in GPS Info with the S4 and had lock in 45 seconds at this location. For easy comparison, I just opened 2 instances of GPS Info and pointed each at the appropriate COM port (7 and 9 in my setup).

I wiill test it against a MTK I bluetooth GPS later and expect it will at least equal the performance of that chip.

Terry
Attached Images
353-comparison.jpg  
Ken in Regina
Thanks for the update and the link, Terry.

The copy of GPSInfo on the CD with my S4 works fine on Win7 Home Premium on my new notebook. But it won't let me launch a second instance. I'll download the one from your link and see if it works better for me.

Re Windows loading the driver when you plug in the S4, my notebook threw an error when it tried to do that. That's why I downloaded it from GlobalSat.

What's the cold start time for the S3 in that same location?

...ken...
tcassidy
While I was away, the BU-353 finally got a fix! I have tried a cold start at this location but can't outwait it...something like 4 minutes. Strange, as I normally depend upon it here.

It wasn't clear whether the MTK1 or BU-353 S4 was a winner. They both gave similar results but the bars were slightly longer for the MTK. Unfortunately, I am unable to use the Cold Start button successfully with the Bluetooth GPS.

Terry
Attached Images
353-comparison_2.jpg   s4-mtk1-comparison.jpg  
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