Patent Description:
UWB positioning is a technology for positioning an object indoors using an extremely narrow pulse response and a bandwidth exceeding <NUM>. A UWB positioning system comprises multiple positioning base stations, and a positioning tag placed on an object to be positioned. The positioning tag transmits a pulse signal, which becomes a pulse response upon reaching the positioning base stations after channel modulation. The UWB positioning system uses the pulse response received by the positioning base stations from the positioning tag to determine the position of the object.

When signal propagation between the positioning base station and positioning tag is line-of-sight propagation unobstructed by any obstacle, the UWB positioning system can obtain an accurate position of the object, but if signal propagation between the positioning base station and positioning tag is non-line-of-sight propagation obstructed by an obstacle, then the position obtained by the UWB positioning system is generally inaccurate.

Thus, in UWB positioning, it is very important that the type of signal propagation between the positioning base station and positioning tag be identified.

<NPL>ET AL, relates to the problem of detecting the channel state between LOS and NLOS conditions using UWB signals.

<NPL>ET AL. , relates to a detailed evaluation of an approach using the amplitude spectrum of the received signal for correlation in the case of real time localization system using impulse radio ultra-wideband.

The embodiments of the present invention provide a method and apparatus for detecting a signal propagation type, a computing device and a machine-readable storage medium, which are capable of detecting the type of signal propagation between a positioning base station and a positioning tag of a UWB positioning system.

A method for detecting a signal propagation type according to an embodiment of the present invention comprises: calculating a similarity value of a currently received pulse response and a reference pulse response when a certain positioning base station of a UWB positioning system currently receives a pulse response from a certain positioning tag, the similarity value indicating the degree of similarity between the currently received pulse response and the reference pulse response, wherein the reference pulse response is a pulse response previously received by the positioning base station from the positioning tag; and determining the current type of signal propagation between the positioning base station and the positioning tag on the basis of the similarity value, and storing the currently received pulse response as the reference pulse response if the determined signal propagation type is not the same as the type of signal propagation between the positioning base station and the positioning tag when the reference pulse response was received.

An apparatus for detecting a signal propagation type according to an embodiment of the present invention comprises: a computing module, configured to calculate a similarity value of a currently received pulse response and a reference pulse response when a certain positioning base station of a UWB positioning system currently receives a pulse response from a certain positioning tag, the similarity value indicating the degree of similarity between the currently received pulse response and the reference pulse response, wherein the reference pulse response is a pulse response previously received by the positioning base station from the positioning tag; and a determining module, configured to determine the current type of signal propagation between the positioning base station and the positioning tag on the basis of the similarity value, and further configured to store the currently received pulse response as the reference pulse response if the determined signal propagation type is not the same as the type of signal propagation between the positioning base station and the positioning tag when the reference pulse response was received.

A computing device according to an embodiment of the present invention comprises: a processor; and a memory, storing an executable instruction which, when executed, causes the processor to execute an operation included in the method described above.

A machine-readable storage medium according to an embodiment of the present invention has an executable instruction thereon; when the executable instruction is executed, a machine is caused to execute an operation included in the method described above.

The solution in embodiments of the present invention uses a pulse response currently received by a positioning base station of a UWB positioning system from a positioning tag, and multiple reference pulse responses previously received by the positioning base station from the positioning tag, to determine the current type of signal propagation between the positioning base station and the positioning tag; thus, the solution in embodiments of the present invention can detect the type of signal propagation between the positioning base station and positioning tag of the UWB positioning system.

Other features, characteristics, benefits and advantages of the present invention will become more obvious through the following detailed description, which makes reference to the drawings.

Various embodiments of the present invention are described in detail below with reference to the drawings. <FIG> shows a general flow chart of a method for detecting a signal propagation type according to an embodiment of the present invention. The method <NUM> shown in <FIG> may be realized by any computing device having computing capability. The computing device may be, but is not limited to, a desktop computer, notebook computer, tablet computer or server, etc..

As shown in <FIG>, in box <NUM>, a certain positioning base station Bi in a UWB positioning system currently receives a pulse response IN from a certain positioning tag Ti.

In box <NUM>, the currently received pulse response IN and a reference pulse response MR are used to calculate a similarity value SV, which indicates the degree of similarity between the pulse response IN and the reference pulse response MR. The reference pulse response MR is a pulse response previously received by the positioning base station Bi from the positioning tag Ti. Here, for an initial reference pulse response MR, it is necessary to manually determine the type of signal propagation between the positioning base station Bi and the positioning tag Ti when the initial reference pulse response MR is received, wherein the type of signal propagation may be line-of-sight propagation or non-line-of-sight propagation.

In one aspect, the similarity value SV is calculated while regarding both the pulse response IN and reference pulse response MR as probability density functions. In this case, the similarity value SV may be calculated using an algorithm, for example but not limited to the KS-test (Kolmogorov-Smirnov test), Chi-Squared test, G-test, Fisher's exact test, binomial test or exact (significance) test, etc. Alternatively, the maximum distance of the cumulative distribution function between the pulse response IN and the reference pulse response MR may be calculated as the similarity value SV.

In another aspect, the similarity value SV is calculated while regarding both the pulse response IN and reference pulse response MR as trajectories. In this case, the Euclidean distance, dynamic time warping, longest common sub-sequence, edit distance, Chebyshev distance, Manhattan distance, Hausdorff distance, Frechet distance, one way distance, cosine similarity, locality in-between polylines, polylines or clue-aware trajectory similarity or a related coefficient value (e.g. root mean square, variance, etc.) between the pulse response IN and the reference pulse response MR may be calculated as the similarity value SV.

In box <NUM>, the current type of signal propagation between the positioning base station Bi and the positioning tag Ti is determined using the calculated similarity value SV. For example but without limitation, if the similarity value SV is greater than or equal to a designated threshold F1, then it is determined that the current type of signal propagation between the positioning base station Bi and the positioning tag Ti is a first signal propagation type, which is the type of signal propagation between the positioning base station Bi and the positioning tag Ti when the reference pulse response MR was received. If the similarity value SV is less than the designated threshold F1, then it is determined that the current type of signal propagation between the positioning base station Bi and the positioning tag Ti is a second signal propagation type, which is another signal propagation type different from the type of signal propagation between the positioning base station Bi and the positioning tag Ti when the reference pulse response MR was received.

In box <NUM>, a determination is made as to whether the determined signal propagation type is the same as the type of signal propagation between the positioning base station Bi and the positioning tag Ti when the reference pulse response MR was received.

In box <NUM>, if the determination result of box <NUM> is negative (N), then the pulse response IN is stored as the reference pulse response MR, and then the procedure continues to box <NUM>. Here, the reference pulse response MR can be updated by means of boxes <NUM> - <NUM>.

If the determination result of box <NUM> is affirmative (Y), then the procedure continues to box <NUM>.

The solution of this embodiment uses a pulse response currently received by a positioning base station of the UWB system from a positioning tag, and a reference pulse response previously received by the positioning base station from the positioning tag, to determine the current type of signal propagation between the positioning base station and the positioning tag; thus, the solution of this embodiment can detect the type of signal propagation between the positioning base station and positioning tag of the UWB positioning system.

Those skilled in the art will understand that although the similarity value is calculated while regarding both the pulse response IN and reference pulse response MR as probability density functions or trajectories in the embodiments above, the present invention is not limited to this. In other embodiments of the present invention, the pulse response IN and reference pulse response MR may also be used to calculate the similarity value by any other method.

Those skilled in the art will understand that although the reference pulse response MR is variable in the embodiments above, the present invention is not limited to this. In other embodiments of the present invention, the reference pulse response MR may also be fixed and non-variable.

<FIG> shows a flow chart of a method for detecting a signal propagation type according to an embodiment of the present invention. The method <NUM> shown in <FIG> may be realized by any computing device having computing capability. The computing device may be, but is not limited to, a desktop computer, notebook computer, tablet computer or server, etc..

As shown in <FIG>, the method <NUM> may comprise, in box <NUM>, calculating a similarity value of a currently received pulse response and a reference pulse response when a certain positioning base station of a UWB positioning system currently receives a pulse response from a certain positioning tag, the similarity value indicating the degree of similarity between the currently received pulse response and the reference pulse response, wherein the reference pulse response is a pulse response previously received by the positioning base station from the positioning tag.

The method <NUM> may further comprise, in box <NUM>, determining the current type of signal propagation between the positioning base station and the positioning tag on the basis of the similarity value.

The method <NUM> further comprises: storing the currently received pulse response as the reference pulse response if the determined signal propagation type is not the same as the type of signal propagation between the positioning base station and the positioning tag when the reference pulse response was received.

In another aspect, the similarity value is calculated while regarding the currently received pulse response and the reference pulse response as probability density functions, or the similarity value is calculated while regarding the currently received pulse response and the reference pulse response as trajectories.

In another aspect, box <NUM> comprises: determining that the current type of signal propagation between the positioning base station and the positioning tag is a first signal propagation type, which is the type of signal propagation between the positioning base station and the positioning tag when the reference pulse response was received, if the similarity value is greater than or equal to a designated threshold; and determining that the current type of signal propagation between the positioning base station and the positioning tag is a second signal propagation type, which is another signal propagation type different from the type of signal propagation between the positioning base station and the positioning tag when the reference pulse response was received, if the similarity value is less than the designated threshold.

<FIG> shows a schematic diagram of an apparatus for detecting a signal propagation type according to an embodiment of the present invention. The apparatus <NUM> shown in <FIG> may be implemented using software, hardware or a combination of software and hardware. The apparatus <NUM> shown in <FIG> may for example be installed in any suitable computing device having computing capability.

As shown in <FIG>, the apparatus <NUM> may comprise a computing module <NUM> and a determining module <NUM>. The computing module <NUM> is configured to calculate a similarity value of a currently received pulse response and a reference pulse response when a certain positioning base station of a UWB positioning system currently receives a pulse response from a certain positioning tag, the similarity value indicating the degree of similarity between the currently received pulse response and the reference pulse response, wherein the reference pulse response is a pulse response previously received by the positioning base station from the positioning tag. The determining module <NUM> is configured to determine the current type of signal propagation between the positioning base station and the positioning tag on the basis of the similarity value.

The apparatus further comprises: a storage module, configured to store the currently received pulse response as the reference pulse response if the determined signal propagation type is not the same as the type of signal propagation between the positioning base station and the positioning tag when the reference pulse response was received.

In another aspect, the determining module <NUM> is further configured to: determine that the current type of signal propagation between the positioning base station and the positioning tag is a first signal propagation type, which is the type of signal propagation between the positioning base station and the positioning tag when the reference pulse response was received, if the similarity value is greater than or equal to a designated threshold; and determine that the current type of signal propagation between the positioning base station and the positioning tag is a second signal propagation type, which is another signal propagation type different from the type of signal propagation between the positioning base station and the positioning tag when the reference pulse response was received, if the similarity value is less than the designated threshold.

<FIG> shows a schematic diagram of a computing device according to an embodiment of the present invention. As shown in <FIG>, the computing device <NUM> may comprise a processor <NUM> and a memory <NUM> coupled to the processor <NUM>. The memory <NUM> stores an executable instruction which, when executed, causes the processor <NUM> to execute the method <NUM> or <NUM>.

The embodiments of the present invention also provide a machine-readable storage medium, having an executable instruction thereon, wherein a machine is caused to execute the method <NUM> or <NUM> when the executable instruction is executed.

Claim 1:
A method (<NUM>) for detecting a signal propagation type, comprising:
calculating (<NUM>) a similarity value, SV, of a currently received pulse response, IN, and a reference pulse response, MR, when a certain positioning base station, Bi, of a UWB positioning system currently receives a pulse response, IN, from a certain positioning tag, Ti, the similarity value indicating the degree of similarity between the currently received pulse response, IN, and the reference pulse response, MR, wherein the reference pulse response (MR) is a pulse response previously received by the positioning base station, Bi, from the positioning tag, Ti;
determining (<NUM>) the current type of signal propagation between the positioning base station, Bi, (Di) and the positioning tag, Ti, on the basis of the similarity value, SV; and
storing the currently received pulse response, IN, as the reference pulse response, MR, if the determined signal propagation type is not the same as the type of signal propagation between the positioning base station, Bi, and the positioning tag, Ti, when the reference pulse response, MR, was received.