4 ms·
> the GPS signal is not a simple RF carrier There is still a simple carrier; the modulation only affects the sidebands (which contain the broadcast data). Als
by zb 12y ago
> the GPS signal is not a simple RF carrier
There is still a simple carrier; the modulation only affects the sidebands (which contain the broadcast data).
Also, don't forget that GPS is a dual-frequency system (civilian receivers don't tend to use the L2 band because they can't decode the data it broadcasts). Finally, the control segment is not limited to passively listening for signals from the satellite - it has the entire resources of the USAF available to it.
- VLM 12y agoHmm thats interesting. I've never seen that on a spectrum analyzer. L1 C/A looks spikey if you zoom out but its really a meg or so wide and only 20 dB or so above the rest of the spectrum anyway. From what I understand of the modulator its not possible to output a carrier other than bleed thru probably 60 dB down or equipment failure. BPSK modulation just doesn't work that way. Maybe you're talking about the L3 signal? I find that part of GPS to be spooky. Or that experimental L5 stuff that I don't know anything about. Everything I do know about GPS is just BPSK and the "old" stuff like L1, L2, etc..