Continue to Site

Welcome to EDAboard.com

Welcome to our site! EDAboard.com is an international Electronics Discussion Forum focused on EDA software, circuits, schematics, books, theory, papers, asic, pld, 8051, DSP, Network, RF, Analog Design, PCB, Service Manuals... and a whole lot more! To participate you need to register. Registration is free. Click here to register now.

Register Log in

GPS antenna on SIM908 - Not Working

Status
Not open for further replies.
M

mihirDG8

Newbie level 3
Newbie level 3
Joined
May 22, 2013
Messages
4
Helped
0
Reputation
0
Reaction score
0
Trophy points
1,281
Activity points
1,310
I am using SIM908. I need to get GPS data and send it over GPRS. Since my size is very small, I have to use smallest possible antenna. My GSM and GPRS are working fine, but for GPS I am struggling.

I have on board AH316M157501 from Taiyo Yuden for GPS. Since this is chip antenna, I have kept GPS_VANT_IN and GPS_VANT_OUT floating. I am getting 0,0,0,0 when I try to read GPS co-ordinates. Can you pls. help me know the root cause?
 

Following is the command sequence I followed for testing,.,,,

Code Sequence 1:

1) AT+CGPSPWR=1 (Turned On GPS Power Supply)
OK

2) AT+CGPSRST=1 (Reset GPS in autonomy mode)
OK

3) AT+CGPSINF=0
0,0.000000,0.000000,0.000000,20101010002259.000,0,0,0.000000,0.000000
OK

--------------------------------------------------------------------------------------------------------------------------------
Code Sequence 2:

1) AT+CGPSPWR=1 (Turned On GPS Power Supply)
OK

2) AT+CGPSRST=0 (Reset GPS in cold mode)
OK

3) AT+CGPSINF=0
0,0.000000,0.000000,0.000000,19800105235945.000,0,0,0.000000,0.000000
OK
 

You try a new antenna.
This mudule SIM is unstable. you should test SIM outside greater than inside.
Or you re-test SIM, may be SIM have a problem.
 

I removed my on board antenna connections and plugged Active antenna of 3-5V. I also connected battery supply to GPS_VANT_IN. But still I get "Location Unknown" and 0,0,0,0 as result.

I am stuck with this and do not find resolution. Pls. help.
 

You try supply VBAT power mode.
After that you use command "AT+CGPSOUT=0" and this time,you use 2 pin GPS_TXD & GPS_RXD. Now, SIM wili leakage of the signal will and send to continous. You may be use Terminal and Comport uart to receive on PC to testing
 
I am using Microcontroller UART port with 3.3V operation to communication with SIM908. The VBAT supply is kept standard mobile battery 3.7V. Also the same 3.7V is connected to GPS_VANT_IN. I am not using GPS_TXD/RXD pins. I only have master UART signals connected between SIM908 and Microcontroller. There is no computer com-port connection in complete testing.
 

Status
Not open for further replies.

Similar threads

Part and Inventory Search

Welcome to EDABoard.com

Sponsor

Back
Top