BC337 Compact Flash GPS FAQ

1.) Q: Why am I not getting any or very weak GPS signals even though my GPS receiver is directly under the windshield glass?
1.) A: Certain vehicles may be equipped with special windshields that contain metal in the glass that prevents GPS and RF signals from being received properly. Customers with these types of windshields must use an exterior GPS antenna for improved results for GPS applications. If you are unsure about whether your vehicle has one of these types of windshields, contact your dealer and request more information. This vehicle list may not be complete and may updated from time-to-time.
See: http://www.e-zpassny.com/static/info/exteriortags.html

2.) Q: How can I confirm the Compact Flash driver is installed properly on Windows platforms?
2.) A: First, connect the GPS receiver to your PCMCIA port.
Third, if question mark or yellow error icon is displayed in the "PORTS (COM&LPT)" or "DEVICES/USB<->Serial" headings, this is an indication that no drivers are currently installed for the GPS receiver.

For installation instructions refer to your product CD-ROM or download the driver from our web-site here and load it.
If the driver was shown already loaded loaded, you would see "Compact Flash OX16CF950 (Com x) under the "PORTS (COM&LPT)" section..
This is your PCMCIA GPS assigned COM Port number to use when configuring any utility or map program to access the GPS data. 

At times the application has a limited number of available communication ports. Under circumstances like this proceed by performing the following:
From your START button, open SETTINGS > CONTROL PANEL > SYSTEM > HARDWARE > DEVICE MANAGER>Ports>Compact Flash OX16CF950 (Com x)>Settings>Advanced. At this point, you may reconfigure your commmunication port. 

NOTE1: Communication Parameters: 9600 bps/ 8 Data Bits/ "None" parity/ "1" Stop bit/ "None" Flow control.
NOTE2: Hardware Configuration set for RS-232


3.) Q: How can I reset the GPS data protocol back to the default NMEA setting?
After changing my GPS receiver to send data to my PC in SiRF format, which was configured using the included SiRFDemo utility program, my GPS receiver's LED is now very dim and no longer is sending data to my mapping application.
3.) A: 1. Leave your GPS receiver un-plugged from a laptop or PDA for approximately 12-days, whereby the internal power for the temporary memory will be discharged and the GPS receiver will return back its default NMEA GPS format.
(For the TN-206 Bluetooth GPS, leave the power switch in the "ON" setting and let the battery completely discharge over 15-hours to achieve the re-set to default NMEA output.)

3.) A: 2.To reset to default NMEA immediately, click here and follow these step-by-step instruction using the SiRFDemo utility.

4.) Q: How can I confirm the Compact Flash driver is installed properly on Windows platforms?
4.) A: 1. First make sure your PCMCIA Adapter is connected to your notebook PCMCIA port.

4.) A: 2. Open your device manager. For example on Windows XP:
right-click on "My computer"
select properties
select "Hardware"
click on "Device Manager

4.) A: 3. Confirm that the Compact Flash hardware is found:
Open the device manager (if it's not open) and look for an entry that states "Ports (COM & LPT)" and verify "Compact Flash OX16CF950 (COMx)" entry is viewed.
If you don't see this, then the Compact Flash device is not being found. Double check that the card adapter is connected in well on both ends.

4.) A: 4. Once again, confirm that the Compact Flash hardware is working properly:
Right click on the "Compact Flash OX16CF950 (COMx)" and select "Properties"
You should see that the current Device status is OK.
If this doesn't seem right, it might be that the driver is not installed or working properly. You can uninstall the driver by selecting the "Driver" tab and clicking uninstall. Then re-install.

4.) A: 5. Confirm that the Compact Flash driver appears as a virtual serial console:
The Compact Flash driver appears as a serial port, so if you expand (click on the '+' sign) by "Ports (COM & LPT)" you should see the usual 2 or so "Communication Ports (COMx)" (depending on how many serial ports your computer has), possibly an LPT port (if your computer has a parallel port) and finally, if the Compact Flash driver is installed properly, "Compact Flash OX16CF950 (COMx)".
Right click on the "Compact Flash OX16CF950 (COMx)".
You should see that the Device status is OK.
If this doesn't seem right, it might that the driver is not installed or working properly. You can uninstall the driver by selecting the "Driver" tab and clicking uninstall. Then re-install.

4.) A: 6. If this all works you should be able to open a terminal emulator on the serial port. You can use HyperTerminal: Start->All Programs->Accessories->Communications->Hyperterminal
When asked for a name type a random name and click on "OK".
A "Connect To" window will appear, with a field labeled "Connect With" and a click box for selecting which COM port. Select the COM port found in step 6 above and click on "OK".
A "Port Settings" window will open. This doesn't matter - click "OK".

Finally in the terminal window you should see a numerous meaningless characters. These are the ASCII representations of the binary data your Intro module is sending out. About every second you should see a new string of characters.

5.) Q: Is this device WAAS enable?
5.) A: Yes, this device is WAAS enabled by default, that are sold by USGlobalSat, Inc and its Authorized Dealers            . Note, receivers with firmware 3.1.1 and above are WAAS enable out of the box.

6.) Q: What datum is used?
6.) A: WGS 84  

7.) Q: Is this device waterproof?   
7.) A: No…       

8.) Q: What's the refresh rate?   
8.) A: GGA(1sec), GSA(5sec), GSV(5sec), RMC(1sec),VTG(1sec)        

9.) Q: What is the output format for this receiver?         
9.) A: Output format: GGA(1sec), GSA(5sec), GSV(5sec), RMC(1sec),VTG(1sec)        

10.) Q: How many satellites are needed for 3-D positioning?   
10.) A: A minimum of 4 satellites (3 for 2-D no altitude)          

11.) Q: Can I reconfigure receiver? If so, what program?           
11.) A: Unfortunately, you cannot reconfigure GPS receiver.

12.) Q: Can I reconfigure receiver's Baud-Rate? If so, what program?        
12.) A: Unfortunately, you cannot reconfigure GPS receiver.

13.) Q: Can I reconfigure receiver's NMEA data? If so, what program?        
13.) A: Unfortunately, you cannot reconfigure GPS receiver.

14.) Q: What platforms are supported?     
14.) A: Pocket PC 2002/2003, Win CE, Win CE.Net, WM2003, Selected Windows Mobile 5 devices.
NOTE: If device is a Windows Mobile 5 Dell Axim X50v/51v download patch from

15.) Q: Why is my GPS loosing connection after a time period?
15.) A: You need the BC337 patch. In which can be retrieved from here

16.) Q: How do I load Dell’s patch on my PDA?
16.) A: First, download patch. Next, cut and paste the compressed file directly in Dell X50v/ X51v. Next, tap "GPSDrvUpdate" file directly from PDA and follow the instructions to complete the installation. Then, your PDA will automatically reboot.
 BC337 patch can be retrieved from here 

17.) Q: Why is my Compact Flash GPS receiver not recognized under my card reader?
17.) A: Compact Flash is not a conventional CF card. Therefore, its design to only operate in both Pocket PC platforms and Windows XP. Note, in laptop applications CF drivers and CF to PCMCIA adapter is require for operation.

18.) Q: Why is my Compact Flash GPS not recognized in my laptop’s expansion port?
18.) A: Compact Flash is not a conventional CF card. Therefore, in laptop applications CF drivers and CF to PCMCIA adapter is require for operation.

19.) Q: What is the Red LED indicator represent?      
19.) A: Satellite status. Red LED Flashing=GPS position is fixed. Red LED Steady= No GPS position is fixed and searching.       

20.) Q: What's the unit's Baud Rate settings? 
20.) A: 4800 bps… 

21.) Q: What is the current BC-337 firmware version?          
21.) A: Firmware version 3.1.1 is the current BC-337 firmware version.          

22.) Q: What is the power consumption for this device?
22.) A: The Power Consumption Rate of BC-337: 90 mA

23.) Q: Will my receiver support older NMEA standards?      
23.) A: Yes, NMEA 2.0 is backwards compatible with older versions of the protocol.

24.) Q: Why is my GEOID and mean sea level is missing which affects the altitude calculations?   
24.) A: Yes, the GEOID correction was missing until it was added in version 3.1 of the firmware from my observations of the Holux 236 that uses it.

25.) Q: How does the "20 channel" affect performance?
25.) A: The sensitivity numbers like the TTFF numbers don't really mean much, as they're hard to tie into real life observations.  

26.) Q: How much more is the SiRF Star III power consumption compare to SiRF Star IIe/LP?
26.) A: About 15% more power hungry than the previous SiRF Star IIe/LP.     

27.) Q: Is SiRF Star III quicker in signal acquisition?    
27.) A: Yes, SiRFStarIII can acquire much faster than IIe/XT2 in difficult environments thanks to the added correlating power and that is not reflected in the dB number.    

28.) Q: How much accuracy is comprised without utilizing WAAS?          
28.) A: Since Selective Availability (SA) was removed in May 2000, the residual GPS error of approximately 10 meters is mostly due to GPS signal deflection that the SBAS system can only marginally correct (I have never been able to measure any improvement from EGNOS but others have seen 1/2 meters with WAAS). On the other hand SBAS is crucial for critical use such as flying a plane as it allows for near real time GPS signal integrity checking.        

29.) Q: What is the biggest benefit of the SiRF Star III chipset?          
29.) A: Correlation power, the action of analyzing the signal received from the satellites and making sense out of it to compute a position. Sounds simple enough, but the signals are very weak (sent from 20,000 kms above our heads) and generally very degraded by our immediate environment, so the more correlation power you have the better your chances are of getting a "fix". In addition, TTFF is less dependent on the environment and once you get a lock you rarely lose it, even indoors. With SiRFIII, GPS requires less "work", for instance, you no longer need to choose between waiting 2 minutes when you leave a parking garage in the morning to get a fix or risk driving around for 10 minutes without one, now you'll generally get a fix in 45 seconds in both situations .          

30. Q: What is the meaning of "baud rate"?   
30.) A: Baud rate is really the rate of bit transitions on the serial data link. Since each byte of data adds a start and stop bit, it is 10 bits long, and 38400 baud is 3840 bytes per second. Faster bit rates transfer more bytes per second, i.e., greater bandwidth.     

31.) Q: What to look for first to know which SiRF firmware version is oldest/newest?
31.) A: Here's a little insight into SiRF version numbers: 2.3.2-GSW2-2.05.024-C1PROD1.0_6A -- the GSW2 means standard SiRFstarII software, and 2.3.2 is the release version number. The 2.05.024 or similar numbers are internal numbers into the engineering data base. C1 is the build variant, a number that varies with each software type, but can relate to flash builds vs. RAM (debug) builds, builds with or without SBAS support (WAAS), builds with one or two serial port support, NMEA or binary protocol default, etc. Prod means this is a released rather than a beta (test) version. 1.00 means the release is without any post-release bug fixes. If there is a letter or letters after the Prod1.00, like Prod1.02b, this would mean that some specific "patches" have been added to provide interim fixes for known bugs. After that, anything on the line is likely added by the manufacturer for internal version control. A number like 0000003729 with XMitac2.0 means this is XTrac 2.0 customized by SiRF for Mitac. In general, an X in the number will imply XTrac software, while GSW2 or GSW3 will indicate standard code for SiRFstarII or SiRFstarIII, respectively.  

32.) Q: Can we upgrade our SiRF firmware? What' s needed for the process?         
32.) A: SiRF provides the new versions to our direct customers, but it is up to them to determine if they want to provide an update mechanism to their end-user customers. While the process is relatively simple, unless there is a hardware way to put the receiver into flash upgrade mode (internal boot mode is our term) there is a chance to get things stuck so you have to send it back to the manufacturer or a repair depot to recover. Further, you must be supplied with a flash programming utility to do the job since you cannot access the flash directly -- you have to go through the ARM processor on the SiRF chipset."

33.) Q: What is static navigation?     
33.) A: Static navigation when enable, velocities lower than 1.2 m/s for 3 seconds we will freeze the position, and leave them frozen until velocity exceeds 1.4 m/s. Static navigation is a mode designed for motor vehicles, which causes the position to become pinned at one location when velocity is determined to be low enough. This is designed to make navigation systems operate more reasonably when the GPS Selective Availability (SA) signal degradation is turned on.

34.) Q: Why does my receiver fail to acquire satellite information after in use from a flight?  
34.) A:
Under GPSInfo, perform a cold start. In result, the BC-337 will reset its registers for terrestrial coordinate calculation.     

35.) Q: What are the differences from SiRF Binary Protocol for SSII SSIII manuals?        
35.) A: Key differences between SS2 and SS3 binary is that SS3 no longer uses as many debug messages (Message ID 255), and instead uses a newer message 225. That message has sub-message IDs, most of which are not defined outside our Engineering department. Sub-ID 6, however, is the TTFF message, which may be of interest. Message 225 is turned on and off just like message 255: use the debug/development message flag in the reset configuration byte of the reset message (message 128).

36.) Q: How important is having WAAS enabled on your GPS receiver?         
36.) A: SiRFstartIII currently does not have WAAS enabled, not that this matters unless you intend on relying on it to operate a plane. 

37.) Q: What satellite identification number is used for WAAS and EGNOS?
37.) A: Satellite #33 (AoRE) is for EGNOS, Satellite #35 (AoRW) is for WAAS, and it has been suggested that Satellite #41 (PoR) will be used to indicate that data is being received from the Japanese MSAS system.

38.) Q: What is trickle mode?  
38.) A: The Trickle mode allows for an increase in battery life by putting the GPS module in sleep mode for very short periods of time, such as 300ms per 1s cycle, which will result in a battery life increase of about 40% according to my testing. It can be useful for certain types of applications but there is a hit on performance as the receiver will have to get "back on its feet" when it wakes up. It is especially problematic in difficult reception conditions. Starting with FW 2.3, SiRF has added the "Adaptive Trickle" mode, which as its name implies will adapt the power savings to the conditions of reception. In optimal conditions, I found that the battery life increase amounts to about 30%.     

39.) Q: Lately it takes too long to lock the satellites. Sometimes it took as long as 7-9 minutes (solid Red LED). Environment: highway, no high trees and buildings. What can I do to correct this?
39.) A: Perform a device reset.

40.) Q: The LED didn't turn red while the unit is inserted in expansion port. What can I do to correct this problem?
40.) A: Be certain the unit is inserted properly in expansion port. If needed, attempt inserting device multiple times.

41.) Q: How do I connect and use a Compact Flash GPS device in Pocket PC?    
41.) A: In order to set up a Compact Flash Connection with a GPS receiver, please see user manual for instructions.   

42.) Q: How do I connect and use a Compact Flash GPS device WinMobile5?
42.) A: Setup is similar to the above question. See user manual for instructions.   

43.) Q: Can I alter the GPS datum?
43.) A: Unfortunately, you cannot alter the GPS datum.

44.) Q: After changing my GPS receiver to send data to my PC in SiRF format, which was configured using the included SiRFDemo utility program, my GPS receiver's LED is now very dim and no longer is sending data to my mapping application. What can I do to correct this problem?
44.) A: F irst... you are required to download SiRF Demo programming utility from  following here

Once this program is downloaded and installed on your laptop or desktop machine, you may proceed executing the following instructions listed below. 

1. Select "OK" on the Data Source Setup.
2. Mirrored Serial Port and Baud Rate settings found in Device Manager ( Device Manager information can be accessed from Start->Control Panel->System->Hardware->Device Manager-> Ports->
For Compact F: Compact Flash OX16CF950 (Com X) 
For USB: Prolific USB-to-Serial Comm Port (COM X)
3. Then, select "Action" followed by "Open Data Source". 
4. Select "Action" followed by "Switch to NMEA Protocol".
5. Finally, at this step click "Send".
6. Exit the program.