Table 1 Table of notations
From: High precision hybrid RF and ultrasonic chirp-based ranging for low-power IoT nodes
Notation | Description |
|---|---|
Δftx | Frequency swing of the transmitted audio chirp, nominal chirp bandwidth. |
Δfrx,x | Frequency swing of the recorded audio chirp at mobile node x. |
Λ | linear increasing and decreasing triangle function. |
τrx | Awake time of the receiving mobile nodes. |
τtx | Audio signal broadcast duration of the transmitting beacon. |
τ′ | − 3 dB bandwidth of the cardinal sine. |
A | Amplitude of the rectangle window function. |
f0 | Carrier frequency of the transmitted audio chirp at the beacon. |
mRF(t) | RF signal to wake up the mobile nodes simultaneously. |
ma(t) | Audio signal broadcast by the beacon. |
〈sc,sc〉(t) | Autocorrelation result of the linear chirps. |
TA | Wake up time of the mobile nodes. |
T0 | Starting time of the audio signal broadcast. |
vs | Speed of sound (340 m/s). |
xz | Distance between the beacon and mobile node z. |