GPS passive antenna | Thales IoT Developer Community
April 15, 2020 - 2:07pm, 1390 views
Hello,
I am using the EHS8 GPS and using a passive antenna, are there any minimum antenna specifications for normal gps operation? The antenna cannot capture the GPS signal and I verified that the configuration is correct. Please I need help.
Hello,
According to the documentation it ***** to be 50 Ohm antenna. An active antenna is recommended especially if the cable is longer than 10cm. What setup do you have - is it a developer board with stock antenna or your own board? Have you checked both AT^SCFG and AT^SGPSC settings? Do you have any other antenna to compare?
Regards,
Bartłomiej
I have no other antenna to compare, the one I use is a router antenna that is specified at 50 ohms. My settings are as follows:
^ SCFG?
^ SCFG: "Audio / Loop", "0"
^ SCFG: "Call / ECC", "0"
^ SCFG: "Call / Speech / Codec", "0"
^ SCFG: "GPRS / AutoAttach", "enabled"
^ SCFG: "Gpio / **** / ASC1", "std"
^ SCFG: "Gpio / **** / DAI", "gpio"
^ SCFG: "Gpio / **** / DCD0", "gpio"
^ SCFG: "Gpio / **** / DSR0", "gpio"
^ SCFG: "Gpio / **** / DTR0", "gpio"
^ SCFG: "Gpio / **** / FSR", "gpio"
^ SCFG: "Gpio / **** / GPSANT", "std"
^ SCFG: "Gpio / **** / HSIC", "rsv"
^ SCFG: "Gpio / **** / PULSE", "gpio"
^ SCFG: "Gpio / **** / PWM", "gpio"
^ SCFG: "Gpio / **** / RING0", "gpio"
^ SCFG: "Gpio / **** / SPI", "rsv"
^ SCFG: "Gpio / **** / SYNC", "gpio"
^ SCFG: "Ident / Manufacturer", "Cinterion"
^ SCFG: "Ident / Product", "EHS8"
^ SCFG: "MEShutdown / Fso", "0"
^ SCFG: "MEShutdown / sVsup / threshold", "0", "0"
^ SCFG: "MEop**** / CFUN", "0", "1"
^ SCFG: "MEop**** / SoR", "off"
^ SCFG: "Radio / Band", "511"
^ SCFG: "Radio / Mtpl", "0"
^ SCFG: "Radio / OutputPowerReduction", "4"
^ SCFG: "Serial / Interface / Allocation", "1", "1"
^ SCFG: "Serial / USB / DDD", "0", "0", "0409", "1E2D", "0058", "Cinterion Wireless Modules", "EHx", ""
^ SCFG: "Tcp / IRT", "3"
^ SCFG: "Tcp / MR", "10"
^ SCFG: "Tcp / OT", "6000"
^ SCFG: "Tcp / WithURCs", "on"
^ SCFG: "Trace / Syslog / OTAP", "0"
^ SCFG: "URC / Ringline", "local"
^ SCFG: "URC / Ringline / ActiveTime", "2"
^ SCFG: "Userware / Autostart", "1"
^ SCFG: "Userware / Autostart / Delay", "0"
^ SCFG: "Userware / DebugInterface", "0.0.0.0", "0.0.0.0", "0"
^ SCFG: "Userware / Debug****", "on"
^ SCFG: "Userware / Passwd",
^ SCFG: "Userware / Stdout", "null" ,,,, "off"
^ SCFG: "Userware / Watchdog", "0"
e ^ SGPSC?
^ SGPSC: "Engine", "0"
^ SGPSC: "Nmea / Output", "on"
^ SGPSC: "Nmea / Freq", "5"
^ SGPSC: "Nmea / Data", "GGA, GSA, GSV, RMC, VTG"
^ SGPSC: "Nmea / Interface", "local"
^ SGPSC: "Power / Antenna", "off"
^ SGPSC: "**** / Antenna", "0"
^ SGPSC: "Assist / Address", "FQDN", "supl.google.com", "7276"
^ SGPSC: "Assist / Data"
^ SGPSC: "Assist / Connection"
it returns the following data to me when I turn on the GPS:
AT ^ SGPSC = "Engine", "3"
^ SGPSC: "Engine", "1"
OK
$ GPGGA ,,,,,, 0 ,,,, M ,, M ,, * 66
$ GPGSA, A, 1 ,,,,,,,,,,,,,, * 1E
$ GPGSV, 1,1,00 ,,,,,,,,,,,,,,, * 79
$ GPRMC ,, V ,,,,,,,,,, N * 53
$ GPVTG ,, T ,, M ,, N ,, K, N * 2C
....
$ GPGGA ,,,,,, 0 ,,,, M ,, M ,, * 66
$ GPGSA, A, 1 ,,,,,,,,,,,,,, * 1E
$ GPGSV, 2,1,08,01,00,000,, 02,00,000,, 03,00,000,, 04,00,000, * 76
$ GPGSV, 2,2,08,05,00,000,, 06,00,000,, 07,00,000,, 08,00,000, * 7D
$ GPRMC ,, V ,,,,,,,,,, N * 53
$ GPVTG ,, T ,, M ,, N ,, K, N * 2C
Hello,
What is the cable length? Does the antenna have the sky visibility? Are you sure it's a passive antenna? GPS switches off automatically if it does not get the fix within some defined time. Please try to switch it on again - please also see this.
Regards,
Bartłomiej
Hello,
The antenna is connected directly to the card without cable, and I am doing tests in an open environment with clear visibility of the sky. The antenna is passive, I got to test setting it to active but the error persists. I will try to get another antenna to proceed with further tests. Thank you!
Hello,
I changed my antenna, it remains passive with the 60 cm long cable and the 50ohm antenna, but I still can't get a GPS signal, but now I can get data from more satellites, I can't find errors, the configuration remains same as above. below is the answer I get:
$GPGGA,,,,,,0,,,,M,,M,,*66 $GPGSA,A,1,,,,,,,,,,,,,,,*1E $GPGSV,4,1,14,03,09,029,,04,00,090,,05,33,177,,16,00,000,*76 $GPGSV,4,2,14,17,00,000,,18,00,000,,19,00,000,,20,00,000,*7F $GPGSV,4,3,14,21,00,000,,22,00,000,,23,00,000,,24,00,090,*76 $GPGSV,4,4,14,25,00,090,,26,48,328,,,,,,,,,*73 $GPRMC,,V,,,,,,,,,,N*53 $GPVTG,,T,,M,,N,,K,N*2C
Hello,
This could confirm that the antenna is contributing to the problem you have. How about you restart the GPS engine few ***** when it switches off without finding a fix. Or if you try A-GPS ****.
Regards,
Bartłomiej