GPS 02 01 / GPS 03 01

This is the Ericsson original GPS receiver that can be used to provide a clock reference to equipment like DUG 20 or DUL 20 or also the SIU 02

The GPS 02 is also called NCD 901 41/1, while the GPS 03 is also called NCD 901 56/1

We're not aware of the exact differences between GPS 02 and GPS 03

gps02.jpg gps02_side.jpg


RJ45 for connection to DUL/DUG/DUW/SIU/TCU

The unit has two RJ45 sockets. They appear to have identical functionality.

The pin-out is as follows:

Pin Name Comment
1 1PPS+ RS-422 1PPS GPS -> DUx
2 1PPS- RS-422 1PPS GPS -> DUx
3 RxD+ RS-422 in direction DUx -> GPS
4 TxD+ RS-422 NMEA in direction GPS -> DUx
5 TxD- RS-422 NMEA in direction GPS -> DUx
6 RxD- RS-422 in direction DUx -> GPS
7 12V supply voltage from DUx -> GPS
8 GND supply voltage from DUx -> GPS

The supply voltage pins on a DUL 20/DUG 20 only provide 3V-4V until the GPS receiver is detected by means of a 1kOhms resistor between 12V and GND. At that point, the DUL sources the full 12V.
But it will want to see at least a 10 mA load to continue providing the 12V !

The 1PPS output signal of the GPS 02 only becomes active once there is a GPS fix.

SMA for connection to GPS antenna

This includes a 5V DC phantom voltage supply for the active antenna.


There is a single green LED.
  • after power up, it takes some dozens of seconds until it first becomes active
  • slow green blinking light indicates powered up but no GPS fix
  • steady green light indicates powered up and GPS fix (1PPS output active)


Ericsson uses some extensions to the typical standard NMEA sentences. For more information, see This scientific thesis about emulating an Ericsson GPS receiver twoards a RBS

GPS 02

$PERC,GPver,GPS 02 01,NCD 901 41/1,R1D,110624*54
$PERC,GPver,GPS 02 01,NCD 901 41/1,R1D,110624*54

GPS 03

looks mostly the same, just with a longer sequence of '1' in $PERC,GPsts and with Glonass satellites in addition to GPS?

$PERC,GPver,GPS 03 01,NCD 901 56/1,R1B,TU8KBU9552.1544*11
$PERC,GPreh,00:00:00 00/00/0000,Other*24

Circuit board pictures

GPS 03

gps03_internal_top.jpg gps03_internal_bot.jpg

GRU 04 01

RF shielding around the ST GNSS Processor was removed.

GRU0402_internal_top.jpg GRU0402_internal_bottom.jpg GRU0402_internal_top_detail1.jpg GRU0402_internal_top_detail2.jpg

Further reading

Files (10)
gps02-nmea-log.txt gps02-nmea-log.txt 18.2 KB laforge, 07/07/2020 08:43 PM
gps02.jpg View gps02.jpg 258 KB laforge, 07/22/2022 07:45 AM
gps02_side.jpg View gps02_side.jpg 288 KB laforge, 07/22/2022 07:45 AM
gps03_internal_top.jpg View gps03_internal_top.jpg 1.47 MB laforge, 08/31/2022 06:25 PM
gps03_internal_bot.jpg View gps03_internal_bot.jpg 1.37 MB laforge, 08/31/2022 06:25 PM
Ericsson-GPS-Emulation.pdf View Ericsson-GPS-Emulation.pdf 3.52 MB laforge, 08/31/2022 06:35 PM
GRU0402_internal_top.jpg View GRU0402_internal_top.jpg 1.12 MB WiFiLuke, 11/21/2023 04:18 PM
GRU0402_internal_top_detail1.jpg View GRU0402_internal_top_detail1.jpg 2.66 MB WiFiLuke, 11/21/2023 04:19 PM
GRU0402_internal_top_detail2.jpg View GRU0402_internal_top_detail2.jpg 2.84 MB WiFiLuke, 11/21/2023 04:19 PM
GRU0402_internal_bottom.jpg View GRU0402_internal_bottom.jpg 863 KB WiFiLuke, 11/21/2023 04:19 PM

Updated by WiFiLuke 3 months ago · 15 revisions

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