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San Jose Navigation BT-48 Bluetooth GPS Review 12th April 2004

Review by Dave Burrows



San Jose (or SA Nav as they are better known as) have brought out their first Bluetooth GPS to market. The new version is dubbed the BT-48. I'm amazed at how small these GPS's are becoming even when they are cram packed with wireless capabilities.


The BT-48 is a about 1cm smaller in length compared to the Fortuna Clip-On, spray painted in a silver metallic look and runs off of 3xAAA batteries. One thing that SANAV have done is listened to what people are saying. Most people get aggravated having a flashing blue light, especially if they're using their GPS at night when driving, and SANAV have responded by not having a Bluetooth light on the GPS.


On the top face of the GPS you have a Power LED and a FIX LED. On the back side (top edge) you have a CHARGE LED a mini-USB data cable socket for charging the GPS (if using NiCad's or Ni-Mh batteries), and an ON/OFF switch. That's it, it can't be more simpler than that! Effectively you could look at this as being a Navman 4400 but smaller.




In The Box

SANav currently ship the BT-48 Wireless GPS with:-

  • SANAV Bluetooth GPS 48 Receiver
  • 3xAAA batteries (we received Duracell's)
  • Car Charging lead with a Y-Adaptor to charge both BT GPS and Pocket PC (5vDC)
  • Software CD
  • Manual


Running the BT-48 through our pre-defined tests, it stacked up quite well. Most may be surprised to know that it doesn't have the normal SiRF chipset, but San Jose's own chipset but does operate in NMEA mode.


I did notice in the early firmware that the BT-48 although it was on the dashboard with a clear view of the sky would sometimes lose satellite fix and drop below a 3D fix, but the re-acquisition was less than a second so this really wasn't a problem, but did set off the alarm in the software I was using to tell you that you had lost a fix. San Jose will have this rectified in the production units.



Bluetooth wise, San Jose say that the unit will talk up to 10 meters away from the host device (Pocket PC/Palm or PC) and will perform up to 6 hours worth on 3xAAA batteries. In our tests we achieved just short of 6 hours but it really does depend on which alkaline batteries you use and if you are using rechargeable batteries, which NiCad's or NiMh rated batteries you are using as this will have an effect on battery performance.




  • Currently the smallest of its kind available on market
  • 16 parallel channels
  • Position accuracy of 15m RMS without SA
  • Cold/Warm/Hot Start Time: 45/35/6 sec
  • Support Standard NMEA-0183 (v.2.3) at 4800 bps baud rate
  • Compatible with Bluetooth devices with Serial Port Profile (SPP)
  • Bluetooth data transmission rate up to 720 kbps with Adaptive Frequency Hopping (AFP) for
    interference immunity
  • Bluetooth 1.1 certified (Class 2)
  • Extremely compact , sleek and lightweight design
  • Superior sensitivity for maximum efficiency
  • Two LEDs at the top of the device indicating GPS, Bluetooth & Battery status
  • 3 AAA Ni-MH embedded rechargeable batteries lasting for 8hrs of use
Frequency L1, 1575.42 MHz
C/A 1.023 MHz chip rate
GPS Fix Data Renewal Rate 1 sec
16 Parallel Channels
DGPS Source Default: None
Programmability WAAS
Antenna Type Built-in Antenna
Accuracy: (DGPS: None)  
Position 15 meters RMS, without SA
Velocity 0.1 meters/second, without SA
Speed Accuracy 0.1 Km/h with signal level higher than -130dBm; speed faster than 40km/h
Bearing Accuracy 0.2 deg with signal level higher than -130dBm; speed faster than 40km/h with course of 45 +/- 0.1o
Acquisition Sensitivity -130dBm
Tracking Sensitivity -138dBm (Fixed position)
Time Accuracy (95%) 1ms (Fixed position)
Time 1ms synchronized to GPS time
Datum WGS-84 (or by demand)
Acquisition Rate Open Sky and Stationary
Reacquisition 2 sec average
Cold Start <45 sec average
Warm Start <35 sec average
Hot Start <6 sec average
Connection Communicate with Host Platform via Bluetooth (Class2) Serial Port Profile (4800 BPS)
Protocol (Default) NMEA-0183 (V2.3) -- DTM, GGA, ZDA, GLL, VTG, RMC
Source 3 AAA 800mAh Rechargeable NiMH Battery
Operating Time 6hr min. after fully charged; in continuous mode; programmable > 6hr
Physical Characteristics :  
Size 42 (W) x 63 (L) x 27 (H) mm
Weight 80g
Environmental Conditions:  
Operating Temperature -20C to 60C
Storage Temperature -30C to + 70C
Relative Humidity 5% to 95%, non-condensing



Problems Encountered

On the pre-production unit we did find that the on/off switch was recessed into the case and if like me, you have no nails then this became a little difficult at times. This can be good to stop the GPS being switched on accidentally when it's in your pocket but I found it a little difficult and had to resort to using the Pocket PC stylus to switch it on/off sometimes.


Suction Mount

San Jose have also just announced the release of an accessory for the BT-48 which is a cradle which allows you to suction the BT-48 to a car windscreen.




The BT-48 is a nice little looking GPS, I was a little concerned about how quick the GPS wear started kicking in on our pre-production unit but was told by San Jose that the pre-production units were hand painted and this wouldn't wear in the production units. Using 3xAAA batteries is great, especially for people out walking/hiking who need extended battery power and can easily pack a few extra batteries into their bag or pocket when out hiking, the downside is it doesn't use an even number of batteries, if you alkaline or rechargeable batteries, they tend to come in packs of four, and if you wanted to recharge batteries in a separate charger then you would have to charge an even number of batteries. GPS Boards, patch antennas and Bluetooth modules are becoming extremely small in size, and it's good to see a company using such small footprints in keeping the size of their product down.




Manufacturers Website http://www.sanav.com
Pocket GPS Contributor Dave Burrows
Pocket GPS Contributor Website http://www.daveburrows.com
Overall Rating 85%
How did we achieve these ratings ? Review Ratings


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