Sparkfun GPSRTK2 f9p UBX fail to connenct

Hello there,
I recently purchased two sparkfun zed-f9p GPS RTK, which I intend to use to locate the px4 drone. on the ucenter software, I have set the uart2 interface protocol of the device as: Protocol in:RTCM3 and Protocol out:UBX+NMEA and Baudrate as 115200. I know the px4 system does not support nmea protocol.
I connected an rtk device and pixhawk4 to qgc on the same computer via two usb cables respectively. But when I connect this rtk device to the gps port of pixhawk4 like an ordinary gps device nsh> gps start -d /dev/ttyS0 -b 115200 -p ubx, the device cannot be connected successfully. qgc terminal shows:

nsh> gps status
INFO  [gps] Main GPS
INFO  [gps] protocol: UBX
INFO  [gps] status: NOT OK, port: /dev/ttyS0, baudrate: 115200
INFO  [gps] sat info: disabled
INFO  [gps] rate reading:              0 B/s

However, if the ash protocol is used, px4 can detect a small number of satellites, but cannot publish sensor_gps messages.

INFO  [gps] Main GPS
INFO  [gps] protocol: ASHTECH
INFO  [gps] status: NOT OK, port: /dev/ttyS0, baudrate: 115200
INFO  [gps] sat info: disabled
INFO  [gps] rate reading:              0 B/s
INFO  [gps] rate position:           0.00 Hz
INFO  [gps] rate velocity:           0.00 Hz
INFO  [gps] rate publication:          0.00 Hz
INFO  [gps] rate RTCM injection:      0.00 Hz
    timestamp: 689759983  (0.000529 seconds ago)
    time_utc_usec: 0
    device_id: 0 (Type: 0x00, UNKNOWN:0 (0x00)) 
    lat: 488456306
    lon: 23570470
    alt: 134100
    alt_ellipsoid: 0
    s_variance_m_s: 0.0000
    c_variance_rad: 0.1000
    eph: 0.0000
    epv: 0.0000
    hdop: 0.0000
    vdop: 0.0000
    noise_per_ms: 0
    jamming_indicator: 0
    vel_m_s: 0.0000
    vel_n_m_s: 0.0000
    vel_e_m_s: 0.0000
    vel_d_m_s: 0.0000
    cog_rad: 0.0000
    timestamp_time_relative: -689759983
    heading: nan
    heading_offset: nan
    automatic_gain_control: 0
    fix_type: 3
    jamming_state: 0
    vel_ned_valid: True
    satellites_used: 6

The base RTK device works fine. The topic gps_inject_data published by qgc could be received on px4.

Well, I followed this tutorial, but I did not receive any valid rtk data. Does anyone have experience with zed f9p of sparkfun please? Can anyone help me?

Thanks a lot.

Forget it! the ubx sentences from f9p are not ASCII. Checkout to v1.13 tag version, and use nmea protocol.