USB GPS FAQ
1.) Q: What chipset is my BU-303 using?
1.) A: SiRF Star II e/LP
2.) Q: Is this device WAAS enable?
2.) A: Yes, the BU-303 serial GPS receiver is WAAS enabled by default, it was sold by USGlobalSat, Inc and its Authorized Dealers.
3.) Q: How important is having WAAS enabled on your GPS receiver?
3.) A: SiRFstartIII currently does not have WAAS enabled, not that this matters unless you intend on relying on it to operate a plane.
4.) Q: What satellite identification number is used for WAAS and EGNOS?
4.) 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.
5.) Q: What datum is used?
5.) A: WGS 84
6.) Q: Is the BU-303 device waterproof?
6.) A: No…
7.) Q: What's the refresh rate?
7.) A: GGA(1sec), GSA(5sec), GSV(5sec), RMC(1sec)
8.) Q: What is the output format for this receiver?
8.) A: Output format: GGA(1sec), GSA(5sec), GSV(5sec), RMC(1sec),( VTG and GLL are optional)
9.) Q: How many satellites are needed for 3-D positioning?
9.) A: A minimum of 4 satellites.
10.) Q: Can I reconfigure receiver? If so, what program?
10.) A: Yes. SirfDemo programming utility. Note, custom settings are temporary until the receiver has exhausted both the internal Super-Cap. Then the receiver will revert back to its original default settings.
11.) Q: Can I reconfigure receiver's Baud-Rate? If so, what program?
11.) A: Yes. SirfDemo programming utility. Note, custom settings are temporary until the receiver has exhausted both the internal Super-Cap. Then the receiver will revert back to its original default settings.
12.) Q: Can I reconfigure receiver's NMEA data? If so, what program?
12.) A: Yes. SirfDemo programming utility. Note, custom settings are temporary until the receiver has exhausted both the internal Super-Cap. Then the receiver will revert back to its original default settings.
13.) Q: Lately it takes too long to lock the satellites. Sometimes it took as long as 7-9 minutes (solid green LED). Environment: highway, no high trees and buildings. What can I do to correct this?
13.) A: Under GPSInfo application select a “Cold Start” to reset receiver’s registers.
14.) Q: Why am I not getting any or very weak GPS signals even though my GPS receiver is directly under the windshield glass?
14.) 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.
15.) Q: What platforms are supported?
15.) A: Windows/ Pocket PC/ Mac OS X/ Linux
16.) Q: What is the recommended maximum cable length for wired GPS devices? USB? Serial?
16.) A: We recommend 1.5m (4.92 ft.)/ 3m (9.84 ft.) cable length for USB/ Serial GPS device. Greater the cable length , less sensitivity quality.
17.) Q: Once set. Is SiRF Binary Protocol a permanent configuration?
17.) A: These settings are temporary.
18.) Q:What can I do to prevent my device from having GRMC NMEA time stamp data problem?
18.) A: There is backed battery for SRAM and RTC (Real-Time Clock) to keep last stored position , date ,time , satellite data. When you power down GPS , backed battery will keep the last data. It can help us to achieve maximum acquisition performance. After a long period of time(about 4 hours, depend on different products) GPS is power off, backed battery will run out and last stored data will lose. When you re-start GPS, last stored data display at first if backed battery is still active. If backed battery is inactive , default parameters will display. Only after new GPS signals are received , correct data will display. It can explain why incorrect date display at first. In short , the receiver requires GPS data to update these parameters.
19.) Q: Does the current USB driver support Mac OS X Tiger?
19.) A: Yes it does…
20.) Q: What's the unit's current draw?
20.) A: Typically 90mA.
21.) Q: What's the TX/ RX voltage?
21.) A: The voltage ratings are set to 5VDC.
22.) Q: Will my receiver support older NMEA standards?
22.) A: Yes, NMEA 2.0 is backwards compatible with older versions of the protocol. NOTE: If your map software (such as Street Atlas 5) requires data sentence GGA, and your GPS (such as the Magellan 3000) does not output GGA, then they will NOT work together.
23.) Q: My device is not being detected by my software using Windows platform. What troubleshooting steps do I take?
1. First, connect the GPS receiver to your USB port.
2. Second, from your START button, open SETTINGS > CONTROL PANEL > SYSTEM > HARDWARE > DEVICE MANAGER.
3. Third, if a 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.If the driver was shown already loaded, you would see "Prolific USB-to-Serial Comm Port (COM X)" under the "PORTS (COM&LPT)" section. This is your USB GPS assigned COM Port number to use when configuring any utility or map program to access the GPS data.
Be sure your GPS map or utility program has been configured to read the assigned COM port.
You may download USB drivers from the following links:
Windows Vista/XP Users: here
Mac OS X Universal Binary Users: here
Mac OS X Leopard Users: here
Linux OS Users: here
Win CE Users: here
ONLY IF A COM PORT WAS ASSIGNED TO THE PROLIFIC DRIVER AND YOUR GPS PROGRAM WAS CONFIGURED TO READ THE CORRECT COM PORT,
AND YOU STILL CANNOT GET GPS DATA, continue with these steps:.
1. From the START button select CONTROL PANEL > ADD or REMOVE PROGRAMS.
2. Select "PL-2303 USB-to-Serial" from the program list.
3. Click on the REMOVE BUTTON
4. RE-BOOT your computer
5. Now re-install the Prolific driver for your USB GPS wither from the CD-ROM or the downloaded file from our web-site.
6. Re-Boot your computer and follow the steps "A" through "C" in the GPS Driver Verification section above.
GPS Test Utility
In the next stage, a GPS test application will be downloaded and used to view the receiver's activity or can be compare with your current loaded mapping application.
This GPS Info program utility will provide you with viewable GPS data information needed for full receiver functionality validation.
You may visit our support webpage and download this utility here.
- First, launch the GPS Info program this will display the Setup page.
- Then from the drop down menu list, select the COM port and enter your computers ASSIGNED COM PORT NUMBER as found in the DEVICE MANAGER.
- The Baud Rate should be set to 4800bps.
Almost instantaneously, NMEA raw data strings will be display at a rate of one second intervals below the configuration settings indicate your GPS driver has been
successfully installed and configured. This GPS Info utility also can provide the user with satellite visibility and blue graphical signal strength representation from real-time satellites synchronization. Note: Three satellites are required for two dimension positioning (Latitude and Longitude). Four satellites are required for three-dimension positioning (Latitude, Longitude and Altitude).
24.) Q: My device is not being detected by my software using Macintosh platform. What troubleshooting steps do I take?
24.) A: In the initial stage, you need to identify if the appropriate drivers were loaded correctly. Two good sources to determine that your device's driver are properly installed are in System Profiler and System Preferences in the Operating System. A full description of instructions of how to access this handy information is provided below.
First, shut your computer down, connect GPS receiver to your USB port and boot your Macintosh computer.
Second, access the System Profiler utility. Select the blue apple icon on the top left hand side of the Apple menu. Then, select the following “About This Mac”->”More Info…”-> Hardware->USB to display device’s detection. Under USB Device Tree, you will view “USB Device” this pertains to your GPS USB receiver. Driver information can be found under USB Device window. Vendor Name, Speed, Product ID, and Bus (mA) will be provided.
If no information is provided, this is an indication that no drivers are currently installed for this device to operate properly. For complete installation instructions visit click here for installation instructions.
You may download USB drivers from the following links:
Mac OS X TIGER (10.4.11) Users: here
Mac OS X LEOPARD (10.5.1) Users: here
MAC OSX PPC (POWER PC) or INTEL USB universal binary TIGER (10.4.11) only: here
Finally, under System Preferences, select Network, Show, and Network Port Configurations. Your device will appear as a “usbserial” device in the Port Configurations box.This completes and confirms that your GPS USB drivers are fully installed and operational.
GPS Test Utility
In the next stage, a GPS test application will be downloaded and used to view the receiver's activity or can be compare with your current loaded mapping application. This GPS Info program utility will provide you with viewable GPS data information needed for full receiver functionality validation.
You may download this utility by clicking on the link provided here
First, launch the GPS Utility program this will display GPS coordinate data.
Select "Settings" from the selections, a small window will appear with Port, Rate and Units fields. Configure the application settings to the following:
Then you may re-select the "Settings" selection to close configurations window.
Select "Monitor" from the selections, a small window will appear with raw NMEA data strings displayed across at a rate of less than one second intervals.
Select "Satellites" a real-time window satellite information can be viewed. Within two-minute window period, your first GPS fix should be acquired. This Satellites window will provide the user with real-time satellite visibility and green graphical signal strength representation from real-time satellites synchronization data. Note: Three satellites are required for two dimension positioning. Two dimension positioning reports position only. Four satellites are required for three-dimension positioning, that is to say position and elevation.
25.) Q: What is static navigation?
25.) 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.
26.) Q: What is trickle mode?
26.) 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%.
27.) Q: Can I alter the GPS datum?
27.) A: Unfortunately, you cannot alter the GPS datum.
28.) 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?
28.) A: First... you are required to download SiRF Demo programming utility 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.