However, these times can be factored out of the analysis by calculating the difference between the TOA measurements generated by different sensors (assuming the signal originates from the same target), giving measurements of the time difference of arrival (TDOA).
So, with precise measurements of the time difference, an attacker can easily trace the tags and break the untraceability property of the protocol.
Some groups are also investigating to use the prompt Cherenkov light [59 61], produced by the absorption of the annihilation photon in the crystal, to improve the measurements of arrival time difference.
A low cost confocal probe based on time difference measurement has been developed.
However, many studies defining leg volume as an endpoint report absolute or relative leg volume differences between different measurement time points [ 3, 23, 24, 27].
It is worth noting that, in the case of TA and UE Rx-Tx time difference measurements, the resolution can be as good as twice the sampling period, i.e., 2Tsamp, which corresponds to a spatial resolution of around 10 m.
For both experiments, there was no substantial difference in optimum measurement time among stages and among H/S ratios, with maximum difference of 0.3 h and 0.4 h respectively.
Earlier intertester reliability studies have usually measured only affected [ 8- 10] or only non-affected shoulders [ 11, 12] and with participant numbers below 35, and ROM has only been measured at one visit or with an insignificant time difference between measurements [ 8, 10- 15].
where k is a time index, dt is the time difference between measurement instances, p k is the position, v k is the velocity, f k is the specific force, g = [0, 0, g] is the gravity, and ω k is the angular rate (all in R 3 ).
