2 ms·
It is absolutely possible. As I wrote elsewhere in the comments, you need to use radios with timestamping that can measure the distance (10cm accuracy is achiev
by jwr 8y ago
It is absolutely possible. As I wrote elsewhere in the comments, you need to use radios with timestamping that can measure the distance (10cm accuracy is achievable). See for example Decawave DW1000 radios.
Use those and you can base your distance estimation on time measurement, rather than signal strength. Amplifiers won't help.
- mrb 8y agoNope, DW1000 can't work in an adversarial scenario. Their ranging algorithm critically depends on the receiver time-stamping the "leading edge" of the first bit of the first byte of the PHY header. This bit is either always 0 or always 1 (it's part of the 802.15.4 data rate field), so an attacker can easily cheat by preemptively sending a 0 or a 1 just before the signal booster can relay the first legitimate bit from the keyfob. This legitimate bit will be received (by the booster) while the preemptive bit is still being transmitted, so the booster can smoothly transition to sending the subsequent legitimate bits, and the receiver will have been completely fooled that the keyfob is nearby. DW1000 is nice but it only works in scenarios where both transmitters and receivers are being honest to each other.