Real time passive radar at home

on the roof I have my radar surveillance antenna which is a 3 m long yagi with seven directors a driven element and a reflector each of the elements are supported by two eyebolts connected to a base plate which means I don't need to drill into the boom and can still move the elements back and forward as I need the driven element is a dipole which is separated by a 3D printed non-conductive base plate there is also a nylon bolt on either side supporting this the feed is COA cable which has been separated into the inner and outer conductors this connects to the common mode choke ballon which presents a high impedance to common mode currents and separates the antenna from the rest of the COA cable the antenna is horizontally polarized which means there is minimal interference from the vertical mast on the bottom here I have the adsb truth antenna at 1090 MHz and on the other side I have my reference antenna which is a telescopic monopole note there is also a small common mod choke here as well the antennas on the roof connect down to the antenna interface box on the bottom of this box there's a 3D printed plate which has 16 n type connectors the eight at the front connect to antennas on the roof and the eight at the back connect inside to the server rack inside the box we have our reference and surveillance antennas for the radar these are Loop backs at the moment as there's no filters or amplifiers in the line the third antenna is the adsb truth antenna which runs at 1090 MHz there's a lot of loss in the RG58 cable at this frequency and I need needed one of these saw filters and low noise amplifiers to boost the signal to reasonable levels the next two are just dummies on the end we have a 5volt connector which comes from the server rack inside and this Powers the adsb filter and LNA these devices here are lightning discharge tubes here you can see we have a gas discharge tube which connects between the center conductor and the body of this connector the cables from the antenna interface box go up through this conduit and through to the server the coax comes into the server room through to the back of the server rack the SDR play RSP Duo is used as the radar receiver with the reference and surveillance channels shown here the RDR is used as the adsb truth receiver and the hack RF is used as a spectrum watch a 5V power supply is used to the antenna interface box all of the signals here are connected to a desktop on the other side of the rack here's the front of the server rack with one of the desktop PCS being the radar processor the code for the radar software is available on GitHub at the moment we support three different software radios primarily the SDR play RSP Duo but we also have support for the usrp and two hack RFS chain together the main thing is setting up the config file where you can set things such as the sampling rate of 2 MHz the center frequency for this example which is 20464 MHz and the device we're using which is the RSP Duo on the delay doppler map we have a Target in the scene detections from the radar software are given by orange dots whereas detections from the truth are given by the Green Dots here we have a flight VZ 418 if we go to the adsb truth display we can see VZ 418 is an aircraft coming into land at adate airport on the x-axis here we have by Static range which is the distance from the receiver to Target plus the transmitter to the Target minus the transmitter to receiver on the y- AIS we have biostatic Doppler which is the same but for Doppler in the direction of the transmitter and receiver looking at the other displays on the radar we have a Max hold display which is useful to show some of the Persistence of the targets essentially we take the last 10 or 20 delay Dopp maps and plot the maximum value for each cell interesting for this target here we can see because it has side bands above and below the main body return that this is something with blades and this is known as a micro doler return if we go back to the adsv display map we can see pole 56 which is a helicopter looking at the other displays we have detections in delay over time this is useful for separating the false alarm detections from the true detections similar for detections in Doppler over time once again you can see that micro Doppler above and below the body return here the Spectrum reference shows our 2 MHz bandwidth and it shows that we have 1 and 1/2 MHz of signal which is is our Digital radio the timing display is useful to see which parts of the signal processing are taking the longest here we can clearly see the Clutter filter and the ambiguity processing are the most demanding parts of the system the API data is shown here every time we refresh we get a new delay doppler map and this is the data that's used to plot similar thing for detection data back to the delay doppler map we can see we have another Target here jst 499 going back to the adsb truth another aircraft coming into land

Channel: 30hours

Views: 196,069

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Id: FF2n28qoTQM

Length: 7min 6sec (426 seconds)

Published: Sat Apr 27 2024