Using spread spectrum transform for fast and robust simultaneous measurement in active sensors with multiple emitters

We present a signal processing algorithm for making robust and simultaneous measurements in an active sensor, which has one or more emitters and a receiver, and which employs some sort of signal processing hardware. Robustness means low sensitivity to time and frequency localized disturbances, and to white noise. This is achieved partly by using a orthogonal spread spectrum transform for modulating the signals transmitted from the emitters to the receiver, and partly by using a number of transmission channels. The method is fast since the signals are short, and since the method does not rely on previously transmitted signals. This also means that only a few calculations are needed. Furthermore, the suggested spread spectrum transform has a low complexity, a high numerical stability, and is easily implemented in simple signal processing hardware. The presented method is therefore suitable for low-cost active sensors.