Sim7600 Problem

Assisted GPS (AGPS) on SIM7600 module does not work

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I recently got a SIM7600G breakout board and wanted to use it with the CGPS functionality for A-GPS. It works with connecting with my SIM to the Internet and all, but when I try to use AT+CGPS=1,3 (UE-assisted mode), I receive the following in response to my setup:

+CGPS: 0

I interpret this as the GPS being turned off in response to this mode being selected.

I am currently interacting with the board via USB and with the “AT Command Tester For Simcom Modules”, so I don’t think it’s a voltage issue as the other final post indicated. My current setup is as follows, all “OK” in response and no errors:


While mode 2 does work (UE-based), this is extremely inaccurate and defeats the purpose of my project. Has anyone ever gotten UE-assisted (A-GPS) mode to work on the SIM7600, let alone any Simcom module? If so, how did you get it to work? Is it a SUPL server issue? Firmware?

Any help would be greatly appreciated!embeddedmobilesimsimcomShareCiteEditFollowFlagasked 13 hours agouser19955651111 bronze badge

  • Just a quick comment. (1) As you said, your test setup, including Mode 2, are all OK except coming to Mode 3 (AT+CGPS=1,3), my first wild guess is that it is not USB/UART problem, because it is all simple serial UART interface, at which level only the level at AT commands are interpreted. (2) If I was doing troubleshooting, I would try the following: (a) Use Windows 7/10 USB to serial adaptor cable, and not Widnows USB to SIM7600 USB, because SIM firmware might not entertain all USB to SUB stuff, / to continue, … – tlfong01 11 hours ago   
  • (b) If you are using Rpi python, you might like to compare and contrast my basic SIM7600 test program with sample outputs: (3) Reference: Rpi3B+ Python … SIM7600 Problem, Asked 1 year, 5 months ago, Viewed 642 times: raspberrypi.stackexchange.com/questions/113992/…. – tlfong01 11 hours ago    
  • (3) Ah, you remind me one thing: I played with Neo-6/7/8 GPS Modules before trying SIM7600 GPS. When I first tried SIM7600 GPS, my first feeling was that its GPS hardware is a bit outdated, comparing to Neo. So I decided to switch back to Neo, with their very user friendly Windows based GUI interface. (4) References: Rpi Neo-6M / Neo-8M GPS Module Setup / Fix / Update Problems (a) electronics.stackexchange.com/questions/557417/… / to continue, … – tlfong01 11 hours ago    
  • (b) raspberrypi.stackexchange.com/questions/113544/…. So my suggestion is to separately test Neo6/7/8/9M first, then come back to SIM7600 with integrated GPS hardware. – tlfong01 11 hours ago    
  • (4) Ah, I also remember another thing. SIM800 “autobaud” function actually did not work as specified in their user manual. And as the saying goes: “there isn’t only one cockroach in the kitchen”, I am not surprised that your problem is another SIM hardware/firmware bug. – tlfong01 11 hours ago   
  • 1@tlfong01 Thank you very much for your replies! I don’t think it’s necessarily a USB/serial communication issue (but tell me if I’m wrong), as all other GPS modes (1 and 2) both work via USB with the “AT Command Tester for Simcom Modules” app, as well as via UART with my Arduino and the serial interface. Given that I am able to relatively quickly obtain GPS coordinates with mode 1 (AT+CGPS=1,1), I imagine that my standalone GPS portion is alright, would you agree? As for autobaud, I made sure that it has been fixed on 115200 in both environments that I tested. – user1995565 1 hour ago
  • 1@tlfong01 What other possibilities do you think I should consider as to why only mode 3 returns 0, indicating that the GPS is now turned off? Please let me know if I misunderstood any advice you gave me. Thanks in advance! – user1995565 1 hour ago
  • Thank your for your confirmation and advice. (5) I am glad to hear that the “autobaud” thing seems to be fixed. (6) I agreed with all you said in your second last comment. I now think that I might have over worried on the USB to USB interface, and suggested you to use UART to USB instead. Please ignore my earlier suggestions. – tlfong01 25 mins ago   
  • (7) I have the feeling that you have almost thoroughly tested all the rest, except the Mode 3 thing. So now I think it is not a good idea to go to test using Neo7/8/9M, because even Neo tests OK, you still need go back the SIM7600 to solve the original problem. – tlfong01 20 mins ago   
  • (8) As I said earlier, I switched to Neo and have not come back to SIM for a long while. So I need to read the documents to refresh my memory. I am now reading the following SIM App Note. Please confirm if you are following the same (old 2016) guide, or let me know if there are other more updated documents you are referring to. (9) Waveshare SIM GPS App Note V1.00: waveshare.com/w/upload/9/92/… – tlfong01 9 mins ago    
  • (9) Ah, it is bed time for me. So good luck and see your tomorrow. Cheers. – tlfong01 just now   Edit   

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