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Appeared on: Friday, August 25, 2006
Globalsat BT-328 Review

1. Introduction

Globalsat BT-328 - Page 1

- Introduction

After the release of the now infamous BT-338 based on the SiRF III chipset , Globalsat recently announced a new GPS device, the BT-328, this time powered by another SiRF chipset, the GSC2. A general overview and its performance are presented in this review, where we compare it with, none other than the BT-338. Do we have a new winner in the GPS race?

- Globalsat BT-328

The BT-328 is the latest Bluetooth GPS from Globalsat, built on the latest SiRF GSC2 low power technology. It combines performance with low cost, creating an entry level BT GPS at a very attractive price. Compatible with any device offering a Bluetooth compliant serial interface, it can provide accurate GPS position information for up to 16 hours continuously.

- Features

• New SiRF GSC2 high performance and low power consumption chipset
• Communications with Host Platform via Bluetooth Serial Profile
• Built-in ceramic patch antenna
• Supports NMEA0183 data protocol
• 3 LEDs to show the status of GPS/Bluetooth/Battery
• Rechargeable Li-ion battery
• Operation time: 16 hours, in continuous mode
• Auto power-off, if Bluetooth is not connected to any devices within 10 minutes
• Bluetooth operation range: 10 m

- Used chipset

The SiRF GSC2 chipset has the following specifications:

1, 1575.42 MHz
C/A code:
1.023 MHz chip rate
12 channel all-in-view tracking
Tracking Sensitivity:
-155 dBm
Position Accuracy:
10 meters, 2D RMS 
0.1 m/s
us synchronized to GPS time
WGS-84 Acquisition Time (Open sky, stationary)
0.1 sec., average
Hot start:
8 sec., average
Warm start:
38 sec., average
Cold start:
42 sec., average
18,000 metres (60,000 feet) max.
515 metres/second (1000 knots) max.
Less than 4g
20 m/sec
Protocol messages:
NMEA 0183 protocol
Output format:
Supports command: GGA, GSA, GSV, RMC, VTG, GLL (VTG and GLL are optional)
Operating temperature:
-20° to 60° C
5% to 95% Non-condensing

Looking at the SiRF GSC2 specs and compared with the SiRF III, we notice the following:

  1. SiRF GSC2 chipset doesn't support WASS/EGNOS
  2. SiRF GSC2 chipset supports 12 channels whereas the SiRF III 20 channels all in view
  3. SiRF GSC2 chipset hot start time is 8secs whereas the SiRF III is 1 sec
  4. BT-328 has 16 hours whereas the BT-338 17 hours operation time
  5. BT-328 is smaller (thinner) than the BT-328 and lighter in weight

2. Package Contents

Globalsat BT-328 - Page 2

For our testing purposes, Globalsat sent us the retail package which includes:

The current price for the product is around US$75.00, as found on Globalsat's web site.

The BT-328 is thinner than BT-328 and we would say more eye catching as well:

There is no external battery, since it is incorporated into the device (1300mAh according to Globalsat). This of course makes a hardware reset a little difficult, since if the device stops responding altogether, you have to open the case to remove the battery, resetting it.

The only available jack is the power, located on the top of the device. Underneath, there is a label with various information, such as the S/N and certification approvals:

The external dimensions are 67.5mm x 45mm x 17mm with a weight of 65gr, making it truly portable. On the front, there are three LEDs showing the status of the GPS, Bluetooth and Battery.

3. Installation and Tests

Globalsat BT-328 - Page 2

- Installation

Installation of the device is very easy. After charging for about 3hours, you can install it either on your PDA or a BT enabled laptop. Remember, that pair key is four zeros (0000), in case the application asks for it. All our tests were carried out on an ASUS A6JA laptop. We recorded all produced data for a pre-selected route with VisualGPSX and later analyzed it with GPSLog.

In order to measure the TTFF ("Time to First Fix" which is the time it takes for a GPS to determine its current position), we used the GPSInfo "Cold Start" function. All tests ran simultaneously, under the same environmental conditions while traveling in an Audi, model A4 2004.

Note: The device couldn't switch to SiRF mode, despite trying all software. After each try, the device returned garbage data, so we had to open the device and remove the battery to reset it. Its best to avoid trying it for now.

- Tests Day One

The first day, we tested the device in daylight conditions under a clear sky and 28°C.

Globalsat BT-338
Globalsat BT-328
Time to First Fix (TTFF)
38 sec
47 sec


Average (in view)
Average (in use)
Average Signal Level (in dB)
Maximum per Satellite
Average per Satellite

The BT-328 showed very good performance with a high 3D Fix % and many Satellites in view/use. The Reception signal levels were also better than the BT-338. Surprising results, which left us eagerly looking forward to see what the next day would produce.

- Tests Day Two

The second day, we tested the device in daylight with a partly cloudy sky and 30°C.

Globalsat BT-338
Globalsat BT-328
Time to First Fix (TTFF)
39 sec
42 sec


Average (in view)
Average (in use)
Average Signal Level (in dB)
Maximum per Satellite
Average per Satellite

This time, the results provide a clear lead for the BT-338. The BT-328 still produced good performance, no major complaints there.

- Tests Day Three ( Indoor Sensitivity)

We placed both receivers inside a house, close to a large window and monitored their performance. The Globalsat BT-328 had a 2D fix, whereas the Globalsat Globalsat BT-338 had a 3D fix with 7 in view and 5 in use satellites.

- Overall impressions

The Globalsat BT-328 is powered by a SiRF GSC2 low power chipset. The new chipset showed good behaviour, with good reception levels, but without reaching of course, the performance of the SiRF III. Indoor performance was less than perfect, whereas the SiRF III shines, even in indoor use.

4. Conclusion

Globalsat BT-328 - Page 3

- Conclusion

Globalsat's BT-328 is intended as a low entry GPS solution, offering good performance at an affordable price. The new design of the Globalsat products is very appealing and eye catching. With a weight of only 65gr, it is so light that you can forget that you are carrying it with you.

In the performance comparison, the newest SiRF GSC2 based device showed excellent performance under ideal conditions (clear sky) but under more adverse conditions, especially indoors, couldn't match the performance of the SiRF III based BT-338. The device could not switch to SiRF mode, which gives power users the opportunity to perform some tweaks and may prove annoying. The SiRF GSC2 consumes less power than the SiRF III, giving the BT-328 almost the same operation times as the BT-338, even though it has a smaller battery capacity than the BT-338.

Overall, we were satisfied with the Globalsat BT-328. Don't forget, this is an entry level GPS product with a good price (US$79.00) and very good performance. Of course, it doesn't have all the features or power of the BT-338, but it is certainly a respectable alternative solution.

The Positive

The Negative

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