Help with GPS Signal Generator

[Simon P]

Hey I bought a GPS Signal Generator (here's the link so that you can actually see it. Link: http://www.dx.com/p/professional-gps-signal-generator-test-module-w-antennas-147378#.VX5USUvWZD0 )

I have tried looking around on how to make one, but I can't seem to get the information I'm looking for. Can anyone tell me what the parts of the device are or what is needed for a basic GPS Signal Generator like that one?


The device is a GPS scrambler, but it only does it for L1 and L2 bands. Is there a way for me to modify this signal generator so that it also scrambles on L5 band?

Thanks

 

[davenn]

why do you want to scramble a GPS signal ?

and considering the L5 band is part of the aeronautical band

L5, Safety of Life[edit]
A civilian safety of life signal (broadcast in a frequency band protected by the ITU for aeronautical radionavigation service), first broadcast for demonstration purposes on satellite USA-203 (a Block IIR-M series satellite), and available on all GPS IIF satellites (and beyond).

Two PRN ranging codes are transmitted on L5: the in-phase code (denoted as the I5-code); and the quadrature-phase code (denoted as the Q5-code). Both codes are 10,230 bits long and transmitted at 10.23 MHz (1 ms repetition). In addition, the I5 stream is modulated with a 10-bit Neuman-Hoffman code that is clocked at 1 kHz and the Q5-code is modulated with a 20-bit Neuman-Hoffman code that is also clocked at 1 kHz.

• Improves signal structure for enhanced performance
• Higher transmitted power than L1/L2 signal (~3 dB, or 2× as powerful)
• Wider bandwidth provides a 10× processing gain
• Longer spreading codes (10× longer than C/A)
• Uses the Aeronautical Radionavigation Services band

L5 navigation message[edit]
The L5 CNAV data includes SV ephemerides, system time, SV clock behavior data, status messages and time information, etc. The 50 bit/s data is coded in a rate 1/2 convolution coder. The resulting 100 symbols per second (sps) symbol stream is modulo-2 added to the I5-code only; the resultant bit-train is used to modulate the L5 in-phase (I5) carrier. This combined signal is called the L5 Data signal. The L5 quadrature-phase (Q5) carrier has no data and is called the L5 Pilot signal.

I am not going even start to tell you how to screw up signals on that band
That could easily lead to criminal prosecutions


Thread closed for the safety of the flying public and others that need security in their safety