Ardupilot that get no Sat Lock

Hi to all.
I am trying to setup my for long unused  Ardupilot + Shield according to the info on the first page of this thread but i am having a problem.

I started as proposed using only the Ardupilot board with the Control (ch 5) connected only.
Did everything as per tutorial but can't get the Sat LED blinking before the GPS Emulator step.
The only way to get a Sat blinking is by entering

#define GCS_PROTOCOL -1
any other option like the
#define GCS_PROTOCOL 0 which is by default there wont make my Sat LED blink.
If now i go on the next step (GPS Emulator) with
#define GCS_PROTOCOL -1
Then i don't get a Sat Lock.
Please help because the tutorial doesn't state what to do if someone has a problem like mine.
I am using a Locosys LS20033 GPS

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  • The Locosys LS20033 that comes with the FY-21AP is also configured at 38400 baud rate by default.

    As per manual page 12

    The interface and features of the GPS circuit board
    TX0:Data transmission. Connect to the FY-21AP RX pin. (Although not used!! Shown on sketch of page 11 )
    RX0:Data receive. Connect to FY-21AP TX pin.
    Interface Features: TTL level
    Baud rate: 38400
    Data bits: 8
    Stop bits: 1
    Parity: None
    GPS Data refresh rate: 10Hz

    So my Locosys LS20033 came with only three wires going to Autopilot (That is the FY-21AP)


    RED-------Vc going to both Vin and Vbackup of the GPS

    Green-----Data Transmission (going to Rx of FY-21AP and in my case the IN (Rxi) of Ardupilot)

    I know i must be tiring you by now but i really appreciate your help.

    I am going to try with all wires connected but right now i have to wait for a replacement cable to arrive.

  • Moderator

    I read through the posts and didn't see anything about you making an adapter cable, so if the gps works on another system using it's default connector, I'd take a close look at the made adapter.  

    Anyway, good luck, hope this helps.


    Links are posted below to the excerpt pasted below (lost the hyperlinks).

    tutorial link:

    Locosys 20031 programming link:

    Using other GPS modules

    Note: only the MediaTek and uBlox modules are officially supported by the DIY Drones dev team. It's possible to use other modules, but we can't offer you more support than the guides below, which may or may not work on your module

    You can use any GPS module in NMEA mode as long as you can set it to 38400 baud and splice on a EM406 connector. One that works very well is the Locosys 20031.

    First you probably need to splice on a EM406 connector to the module so it can attach to ArduPilot. Here's a tutorial to do that.

    Then you will probably have to program your module to work properly with ArduPilot. Each module has its own programming commands, which you can usually find on the manufacturer's website. Here's our guide for programming the Locosys 20031.

    Finally, to use a generic GPS module in NMEA mode, set this line of the ArduPilot configuration file to 0:

    #define GPS_PROTOCOL 0 // 0 = NMEA, 1=SIRF, 2=uBlox, 3 = ArduIMU, 5 = Simulated GPS mode (Debug)
  • Tried all firmwares from 2.4 to 2.7.1 which i think is the latest and nothing.

    Actually in 2.7.1 everytime i select the NMEA in the GPS_PROTOCOL i get no flashing blue led at all anymore.

    If i choose any onter protocol the led flashes.

    Why my board is not accepting NMEA at all.

    I rechecked the GPS module on a different autopilot (FY21ap) and it locks in 30 seconds.

    The GPS is working and i have it connected in the vertical pins in front of the uBlox connector GND to -, 3V to Vc and IN to Tx.

    I even used another GPS module of the same company also NMEA and nothing.

    ANY help?

  • Probably i have to do that. I will start with 2.4 then and see from there.

    Thank you

  • Teo,

    What are you trying to do with the Ap?

  • I have to say that the GPS is in 38400 baud by default.

This reply was deleted.