What will happen if every single car has radar? Wouldn't they interfere? You're stuck in traffic and 300 nearby cars are blasting radars all over the place?
In order to create interference between two radars, the ramps have to overlap pretty exactly, within a few nanoseconds of each other. This is very unlikely to happen.
Modern radars employ technologies to detect and/or avoid such collisions.
Overall it is not really an issue, even with many radars in crowded spaces.
If you're on the road in a relatively affluent area where people drive late model cars, this is pretty close to already the case. Automakers have started making these systems standard on many/all of their models in the US for several years now. Toyota, for example, started rolling out these systems a decade ago, and have been standard on all US models since 2018.
I'm not sure what these systems use in practice for interference mitigations, but there's a bunch of stuff that could be done, for instance, hopping between different frequencies.
There are mitigation techniques like randomization of chirp frequencies, choosing different idle times between frames, and signal processing techniques to try to detect interference and filter it out. In the general case, FMCW techniques will always have interference problems.
This is one reason amongst many others that military radars do not use FMCW but instead coded pulse compression techniques.
Co-channel Wifi interference is real. It really puts a damper on range and throughout compared to how it used to be. It is a largely unmitigated clusterfuck, as is the way with CSMA/CA once density increases enough.
LTE interference isn't an important thing in practice, in part because because all participating devices have very tightly-controlled timings. It isn't a clusterfuck at all because of the mitigations in place, but it does require centralized coordination to be this way.
Radars on cars don't have centralized coordination (do they?). What mechanism prevents their performance from degrading as wifi does?
How do I discern those individually-received pulses from the very similar pulses that are being received from other transmitting vehicles? (Sure, their timings should be be different, and the pulses may be very brief. But they may also overlap rather significantly, and errors can be very bad here. We need some rather good certainty here -- however that certainty is accomplished.)
To answer these questions, we need to consider several key aspects of radar technology and signal processing. Let's break it down:
Identifying your own pulses: The main ways to distinguish your own reflected pulses from other sources are:
a) Frequency: While there is Doppler shift due to moving targets, the shift is typically small compared to the carrier frequency. Modern radars use sophisticated signal processing to account for and measure this shift.
b) Pulse coding: Radars often use unique pulse patterns or modulation schemes. This allows the receiver to correlate incoming signals with the known transmitted pattern, effectively filtering out other sources.
c) Timing: The time delay between transmission and reception is used to calculate distance. Signals arriving at unexpected times can be filtered out.
d) Direction: Using directional antennas or phased arrays, the radar system knows where it's transmitting and expects returns from that direction.
Dealing with weak reflections and interference: a) High sensitivity receivers: Modern radar systems use very sensitive receivers to detect weak return signals.
b) Signal processing: Advanced digital signal processing techniques can extract weak signals from noise and interfering sources.
c) Frequency diversity: Some systems use multiple frequencies to improve detection and reduce interference.
Discerning from other vehicle transmissions: a) Frequency allocation: Automotive radars typically operate in specific frequency bands. Within these bands, individual systems may use slightly different frequencies.
b) Time diversity: The probability of pulse overlap decreases with shorter pulse durations. Many modern systems use very short pulses or continuous wave techniques.
c) Spatial filtering: Directional antennas help focus on specific areas, reducing interference from other directions.
d) Signal characteristics: Different radar systems may use distinct modulation schemes, pulse repetition frequencies, or other signal characteristics that can be used to differentiate them.
Bad human.
If I wanted a hyper-confident response that is unfettered by such constructs as context and introspection from a bot I already know where to find one.
Sincerely,
Not a fucking bot.
If you had written it, I'd be willing to discuss exactly why I think that about this prose.
But you did not write it, and I have zero interest in conducting a third-party discussion with a bot.
Now consider how many bits of information is collected by these radars per second.
That gives and indication of how much free bandwith there is in the radar bands if the radars are built at the level of sophistication we expect from wifi. (At an OOM level, if not accurately).
Any congestion with current technology would be because the technology is far less optimized and standardized than wifi.
Even with 10 cars trying to scan the same region, that's about 5 OOM of headroom compared to wifi.
Also consider what modern military radiation radarss can do. The F-35 can actively track 50 targets, all in one direction. And it can do that while potentially 100s of aircraft all are sending radar beams into the same space, with some even activelly trying to jam the F-35 radar.
Obviously, really old and cheap radars can have interference issues. But any such limitation is not due to the Physics or even engineering, but rather on the cost of a radar sophisticated enough to handle its environment.
Any idea what the range of influence on the noise floor is/will likely be?