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EVK-F9T - User guide 

UBX-21040453 - R01 

Troubleshooting

  

Page 18 of 23 

C1- Public  

 

9

 

Troubleshooting 

My application (e.g. u-center) does not receive anything 

Check whether the blue LED on the evaluation unit is blinking. Also make sure that the USB cable is 
properly connected to the evaluation unit and the PC. By default, the evaluation unit outputs NMEA 
protocol on Serial Port 1, or on the USB.  

My application (e.g. u-center) does not receive all messages 

When  using  UART,  make  sure  the  baud  rate  is  sufficient.  If  the  baud  rate  is  insufficient,  GNSS 
receivers  based  on  u-blox  F9  GNSS  technology

 

will  skip  excessive  messages.  Some

 

serial  port 

cards/adapters (i.e. USB to RS232 converter) frequently generate errors. If a communication error 
occurs while u-center receives a message, the message will be discarded. 

My application (e.g. u-center) loses the connection to the GNSS receiver 

u-blox  F9  positioning  technology  and  u-center  both  have  an  autobauding  feature.  If  frequent 
communication errors occur (e.g. due to problems with the serial port), the connection may be lost. 
This happens because u-center and the GNSS receiver both autonomously try to adjust the baud rate. 
Do not enable the u-center autobauding if the GNSS receiver has the autobauding flag enabled. 

The COM port does not send any messages 

Be sure that the slide switch at the front panel is set to I2C and not SPI. In SPI mode the RS232 pins 
on the DB9 connector are switched off and the RxD and TxD output at the front panel are used for SPI 
(MISO, MOSI). 

 

After changing the slide switch, always reset the EVK; if it is not reset, the change will not take 
place.   

Some COM ports are not shown in the port list of my application (e.g. u-center)  

Only the COM ports that are available on your computer will show up in the COM port drop-down list. 
If a COM Port is gray, another application running on this computer is using it. 

The position is off by a few dozen meters 

u-blox  F9  GNSS  technology  starts  up  with  the  WGS84  standard  GNSS  datum.  If  your  application 
expects a different datum, you will most likely find the positions to be off by a few dozen meters. Do 
not forget to check the calibration of u-center map files.  

The position is off by hundreds of meters 

Position  drift  may  also  occur  when  almanac  navigation  is  enabled.  The  satellite  orbit  information 
retrieved from an almanac is much less accurate than the information retrieved from the ephemeris. 
With an almanac only solution, the position will only have an accuracy of a few kilometers, but it may 
start  up  faster  or  still  navigate  in  areas  with  obscured  visibility  when  the  ephemeris  from  one  or 
several satellites have not yet been received. The almanac information is NOT used for calculating a 
position, if valid ephemeris information is present, regardless of the setting of this flag. 

In NMEA protocol, position solutions with high deviation (e.g. due to enabling almanac navigation) can 
be  filtered  with  the

 

Position  Accuracy  Mask.  UBX  protocol  does  not  directly  support  this  since  it 

provides a position accuracy estimation, which allows the user to filter the position according to his 

requirements. However, the ‘Position within Limits’ flag of the UBX

-NAV-STATUS message indicates 

whether the configured thresholds (i.e. P Accuracy Mask and PDOP) are exceeded. 

TTFF times at startup are much longer than specified 

At startup (after  the first position fix), the  GNSS receiver performs  an  RTC calibration to  have  an 
accurate internal time source. A calibrated RTC is required to achieve minimal startup time. 

Summary of Contents for EVK-F9T

Page 1: ...EVK F9T Evaluation kit User guide Abstract This document describes the structure and use of the EVK F9T evaluation kit and provides information for evaluating and testing u blox F9 positioning techno...

Page 2: ...he final product specification This document applies to the following products Product name Ordering code Firmware version Application version PCN reference Product status EVK F9T EVK F9T 10 TIM 2 20...

Page 3: ...3 3 Default interface settings 6 4 Device description 8 4 1 Interface connection and measurement 8 4 2 Active antenna 8 4 3 Evaluation unit 8 4 3 1 Antenna connector RF IN 8 4 3 2 Timepulse connector...

Page 4: ...RCB F9T 1 and LEA F9T 10B Table 1 List of products supported by EVK F9T evaluation kit 1 2 Kit includes The delivered package contains Compact 105 x 64 x 26 mm EVK F9T evaluation unit Micro USB cable...

Page 5: ...operating temperature 40 C to 65 C Table 2 EVK F9T specifications 2 1 Safety precautions EVK F9T must be supplied by a PS1 class limited power source See section 6 2 2 4 of IEC 62368 1 2018 5 for more...

Page 6: ...l the USB driver automatically from the Microsoft Windows Update service To evaluate with the Windows 7 and 8 operating systems the u blox GNSS standard driver x64bit is needed which can be found in t...

Page 7: ...r u blox cellular modules operated in slave mode only Default messages activated as in UART1 Input output protocols available as in UART1 Maximum bit rate 400 kb s SPI Allow communication to a host CP...

Page 8: ...t Front panel Rear panel Figure 2 EVK F9T evaluation unit front and rear panels 4 3 1 Antenna connector RF IN An SMA female jack is available on the front side see Figure 2 of the evaluation unit for...

Page 9: ...onnector can only have the UART 1 input Connect using a straight RS232 serial cable with male and female connectors to the port on your PC The maximum cable length is 3 meters To configure the RS232 p...

Page 10: ...rface I2C is selected SPI In this selection the EVK operates only with the SPI interface The RS232 DB9 port is switched off 4 3 8 Pin header This 14 pin test connector provides additional functionalit...

Page 11: ...r supply connected to the test connector by using standard adapter cables from the manufacturer Hirschmann Table 6 shows an example for overall current measurement When connecting the 3 3 V digital in...

Page 12: ...enter tracking mode can be reduced by downloading aiding data from the AssistNow Online service To measure the total GNSS supply current with EVK F9T follow these steps 1 Power up EVK F9T 2 Connect a...

Page 13: ...EVK F9T User guide UBX 21040453 R01 Block diagram Page 13 of 23 C1 Public 6 Block diagram Figure 6 EVK F9T block diagram...

Page 14: ...U BLOX ZED F9T 10B 40 85C C1 C2 C4 C6 C8 C9 CAP CER X5R 0402 TY 1U0 10 6 3V C3 CAP CER X5R 1210 10U 10 10V C5 CAP CER X7R 0402 10N 10 16V 55 125C C7 CAP CER COG 0402 47P 5 25V C10 C11 C12 C13 C14 C15...

Page 15: ...THICK FILM CHIP 0402 27R 5 YAGEO 27R 5 0 063W 55 155C R5 RES THICK FILM CHIP 0402 10K 5 0 1W R6 R7 R8 R9 R10 R15 R16 RES THICK FILM CHIP 0402 100K 1 0 063W R11 R12 RES THICK FILM CHIP 0402 100R 5 0 1...

Page 16: ...EVK F9T User guide UBX 21040453 R01 Schematic Page 16 of 23 C1 Public 8 Schematic Figure 8 Schematic EVK F9T GNSS Antenna supervisor Supply...

Page 17: ...EVK F9T User guide UBX 21040453 R01 Schematic Page 17 of 23 C1 Public Figure 9 Schematic EVK F9T Connectors...

Page 18: ...t of my application e g u center Only the COM ports that are available on your computer will show up in the COM port drop down list If a COM Port is gray another application running on this computer i...

Page 19: ...olatile memory In order to save them permanently sending a second command is required This allows testing the new settings and reverting to the old settings by resetting the receiver if the new settin...

Page 20: ...an impact on signal travel time The position of the GNSS receiver is typically not the same between two tests Comparative tests should therefore be conducted in parallel by using one antenna and a sig...

Page 21: ...ription UBX 21048598 3 ZED F9T Integration manual UBX 21040375 4 u center User guide UBX 13005250 5 Information technology equipment Safety Standard IEC 62368 1 2018 For product change notifications a...

Page 22: ...Kit I2C Inter Integrated Circuit bus ESD Electrostatic Discharge Galileo European navigation satellite system GLONASS Russian navigation satellite system GND Ground GNSS Global Navigation Satellite Sy...

Page 23: ...ional Office China Beijing Phone 86 10 68 133 545 Email info_cn u blox com Support support_cn u blox com Regional Office China Chongqing Phone 86 23 6815 1588 Email info_cn u blox com Support support_...

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