开云体育Hi All,I am certainly no expert here, but my experience with GPS problems have mainly been due to severe multipath in high rise city areas giving erroneous location data or thick trees in heavily wooded areas blocking the GPS signal altogether. I would have thought that a basic normal GPS receiver (like a Garmin Etrex, etc) would be able to determine GPS satellite coverage and if the?reported position is erratic, suspect jamming or spoofing. The TinySA Ultra should be able to locate the jammer. The use of a directional antenna should enable narrowing down the source or at least the direction. If you are really serious, I would also use a band pass filter, or a combination of a high pass and a low pass filter between the antenna and the TinySA. By using pre-selection, you could enable the internal LNA and drop the noise floor even further. Even if it is a more sophisticated spread spectrum jammer, you should be able to see a "bump" in the noise floor as you sweep the antenna through its location. I agree the use of a normal GPS puck is impractical because it is basically omnidirectional as stated by others AND it requires power. Cheers...Bob VK2ZRE On 5/02/2024 1:05 pm, chri5k via
groups.io wrote:
GPS antenna's like the one linked are tuned to two specific frequency ranges 1165-1278MHz and 1559-1612MHz. In those bands, it has gain of ~6dBi at 90 degrees elevation. At ~20 degrees elevation, it drops to 0dBi. So a 3D cone shaped pattern facing upwards. The LNA is mostly there to overcome cable losses. As mentioned earlier, the GPS system uses spread spectrum and digital signal processing to distinguish the signal from the noise. The receiver is able to tell the direction, distance and elevation angle of the satellites by processing time delays, doppler shifts and carrier phase measurements. Hence my suggestion to use a GPS receiver, antenna and software to accomplish the OP's tasks instead of a spectrum analyzer. |
