Motion detector based on the doppler principle
AssigneeSiemens Building Technologies, Inc.
InventorStefan Hegnauer
Life of this patent
Estimating the term…
Abstract
A motion detector based on the Doppler principle contains a microwave module for emitting a microwave signal containing at least two frequencies into a room under surveillance and for receiving the radiation reflected from the latter. An evaluation stage is connected to the microwave module and generates first and second Doppler signals from the received radiation. The first and second Doppler signals have a phase difference which is proportional to the distance of an object reflecting the microwave signal. The phase difference is determined by an integral transformation. In addition, the relative size of an object and the direction of travel of an object reflecting the microwave signal can be determined by the evaluation stage.
Claims19
A motion detector based on the Doppler principle, comprising:
- a microwave module for emitting a microwave signal containing at least two frequencies into a room under surveillance and for receiving reflections of said microwave signal;
- and
- an evaluation stage which is operatively coupled to the microwave module and in which the received reflected microwave signal generates first and second Doppler signals that have a phase difference proportional to the distance of an object reflecting the microwave signal, said evaluation stage applying said received reflected signal to an integral transformation to determine said phase difference.
A motion detector based on the Doppler principle, comprising:
- a microwave module for emitting a microwave signal containing at least two frequencies into a room under surveillance and for receiving reflections of said microwave signal;
- an evaluation stage which is operatively coupled to the microwave module and in which the received reflected microwave signal generates first and second Doppler signals that have a phase difference proportional to the distance of an object reflecting the microwave signal, said evaluation stage applying said received reflected signal to an integral transformation to determine said phase difference, and further comprising first and second signal channels, said channels being coupled downstream of the microwave module, said chanels amplifying and filtering the received reflected signals which are each fed to an analog/digital converter to provide digitized reflected signals and wherein the integral transformation further comprises integrating the absolute values of the digitized reflected signals in the two channels resulting in values I1 and I2, integrating a multiplication product of the digitized signals resulting in a value I3 and applying the resultant integrals to determine at least one of distance, target type, direction, and velocity.
A method for detecting a target within a measurement space using a Doppler motion detector which generates at least first and second signals which provide at least first and second reflected signals, the method comprising:
- receiving the first and second reflected signals;
- integrating the absolute values of the first reflected signal (I1) and second reflected signal (I2);
- integrating the product of the first and second reflected signals (I3);
- determining the phase difference between the first and second reflected signals as I3/(I1*I2);
- and
- estimating the distance of a target as the absolute value of the phase difference.
Dependencies are inferred from the claim text.