compiling gps-sdr-sim-realtime using usrp X310

[bikilay]

when i try to compile with "$ gcc gpssim.c -lm -O3 -o gps-sdr-sim" compiler on ubuntu using usrp X310, the following error generated.....the error is pointing in to "socket.c" which is about connecting to TCP.......

$ gcc gpssim.c -lm -O3 -o gps-sdr-sim In file included from gpssim.c:14:0: socket.c: In function ‘timem’: socket.c:41:2: warning: implicit declaration of function ‘gettimeofday’ [-Wimplicit-function-declaration] gettimeofday(&t, NULL); ^~~~ socket.c: In function ‘udprecv’: socket.c:60:41: warning: passing argument 6 of ‘recvfrom’ makes pointer from integer without a cast [-Wint-conversion] return recvfrom(s, dataa, siz, 0,&from,sizeof(from)); ^~ In file included from /usr/include/x86_64-linux-gnu/sys/socket.h:269:0, from socket.c:2, from gpssim.c:14: /usr/include/x86_64-linux-gnu/bits/socket2.h:64:1: note: expected ‘socklen_t restrict {aka unsigned int restrict}’ but argument is of type ‘long unsigned int’ recvfrom (int fd, void *restrict __buf, size_t n, int flags, ^~~~ In file included from gpssim.c:14:0: socket.c: At top level: socket.c:63:30: warning: excess elements in array initializer double llhr[3]={39.68,139,76,10}; ^~ socket.c:63:30: note: (near initialization for ‘llhr’) gpssim.c: In function ‘usage’: gpssim.c:1651:9: warning: format ‘%f’ expects argument of type ‘double’, but argument 2 has type ‘char *’ [-Wformat=] printf("Usage: gps-sdr-sim [options]\n" ^~~~~~~~ gpssim.c:1665:3: " -n Use TCP connect to Gnuradio TCP-Source for\n realtime simulation.\n",

@bikilay

[osqzss]

Which source code did you try to compile? It seem not the one in the master repository.

[bitdust]

for usrp, you can try my realtime fork:https://github.com/bitdust/gps-sdr-sim

[bikilay]

I am using the source code from gps-sdr-sim-realtime. I used gps-sdr-sim-master and able to lock or fix position by generating .bin file and transmitting it over USRP......but here i could only use downloaded brdc file instead of real satellite signal....know I am trying to spoof position by using real signal which comes directly from satellite outdoor...

[osqzss]

u-blox receiver provides raw navigation message stream in hex format. Read the current ephemeris from the stream and feed it to the simulator.

[ferorted]

Hi. Anyone can explain how to feed the simulator from ublox receiver output? Can I get the message stream in hex format from receiver usb port? then, so how feed this stream to gps-sdr-sim-realtime?

Thank you

[bitdust]

you can use u-center software to extract & save the the ephemeris data. or use rtklib to receive from ublox and parse the RAW output to get the ephemeris file.

[ferorted]

Thanks for the answer. However, I really want to simulate a static location on the fly. I mean, receiving raw ephemeris and Nav messages from usb port of Ublox receiver, modifying it with gps-sdr-sim (to obtain a preset static location) on the fly and feed the SRD. No one time but continuously. Is it possible?

[bitdust]

as far as i know, gps-sdr-sim doesnt have a 'stream mode' to produce signal stream~ so you cant manipulate messages 'on the fly'. i tried use gnss-sdr and gps-sdr-sim to do this job but failed : orignal signal --> GNSS-SDR --> message stream --> modify data ---> gps-sdr-sim because it needs too much coding works.

[FayeWong98]

This is a question worth discussing. Has anyone implemented this function? I look forward to more discussions.