Herbert Schweinzer

High resolution ultrasonic distance measurement in air using coded signals

This paper gives a survey of problems of ultrasonic distance measurement systems with regard to applicability in industrial environment as well as for presence detection and also for high resolution measurement tasks. The impulse compression method is able to handle the mentioned problems. To simplify the real time signals processing a one bit correlation technique is introduced. Next, the comparison between A-B-measurement and use of passive reflection leads to a new method of active reflection in ultrasonic systems which combines the advantages of both methods. The active and passive reflection is compared and their common and different aspects are shown. In the following the radiation pattern of an ultrasonic transducer is analyzed and its influence on broadband signal emission and reception in conjunction with correlation based receivers is discussed. A prototype of an active reflection system is presented and its final configuration is shown.

LOSNUS: An ultrasonic system enabling high accuracy and secure TDoA locating of numerous devices

This paper presents an indoor positioning system called LOSNUS (LOcalization of Sensor Nodes by Ultra-Sound). It offers high accuracy of ∼10 mm, a locating rate up to ∼10 cycles/s and is applicable for both tracking mobile and locating static devices. LOSNUS is mainly designed to localize static devices especially in a wireless sensor network (WSN) with numerously deployed sensor/actuator devices which enables substantially improving a lot of aspects of applications, e.g. network integration of nodes, supplying node locations to application programs, supervising locations with respect to accidentally dislocating, automatic setup and detecting faking of node locations. In order to deal with the demand of locating static devices, the system is optimized for cheap implementation and on the other hand for a high resolution of locations. Concept and basic operation, realization of system components and low-cost receiver principles, improved system performance and setup of a test system will be discussed in this paper.

Dependency of correlative ultrasonic measurement upon transducer's orientation

The pulse compression method adds several improvements to ultrasonic distance measurement systems. Especially in conjunction with the one bit correlation method, which eliminates the amplitude influence and offers real time possibilities several advanced applications become possible. After a survey of several measurement variants the influence of the orientation of a piston modeled transducer is examined to realize two most attractive cases. At last some measurements on real transducers are presented to verify the supposed model of the piston membrane.

A model for the analysis of the fault injection process

Results of fault injection experiments performed under different conditions can only be related to each other, if their interpretation is based on a thorough understanding of activation and propagation of faults and errors. We analyze these processes by applying a special layer model of a computing system. Our aim is to model the transformation of a fault on a signal line into a system failure as the propagation of erroneous information through multiple layers. Two specific layers that describe the fault activation process have been sufficiently completed and are presented here. A quantification for these is derived and different applications are summarized. Excellent correspondence between analytical results based on modeling and experimental data is found. A prediction of fault activation with high accuracy is possible, as well as a quantitative evaluation of the effect of synchronizing fault injection.<<ETX>>

High Resolution Ultrasonic Distance Measurement Systems Using Pulse Compression and Their Applications

Ultrasonic distance measurement in air is broadly used for industrial and commercial low cost applications with medium or small resolution. Configurations for the applications are usually restricted to passive reflection and A-B measurement. This paper gives a survey of the ultrasonic distance measurement method with high resolution based on pulse compression. Improvements resulting from this method include good noise suppression, possibility to operate several systems in parallel without disturbing influence of cross talk, and high measurement rate. Modified configurations and the available high resolution lead to new applications which are summarized.

A 3D Airborne Ultrasound Sensor for High-Precision Location Data Estimation and Conjunction

Airborne ultrasound represents a robust tool for gathering 3D scene information especially in terms of robotics. We present an ultrasound sensor for high precision determination of reflection points in a specular environment, optimized for the suppression of deviations caused by air turbulence. By joining data of measurements from different positions an improved estimation of basic geometric objects, especially of curved objects is reached.

A 3D-LOCATION SYSTEM OPTIMIZED FOR SIMPLE STATIC AND MOBILE DEVICES

Abstract This article focuses on 3D-location systems based on ultrasound time-of-flight (TOF) measurements. Commonly, location systems localize mobile devices with base stations. However, our concept is primarily oriented to simple static devices, especially sensors measuring local physical quantities. Normally the sensor-identification, established at system setup, allows to link sensor data and sensor location. Using locally measured TOFs of ultrasonic signals instead of an explicit identification, the device directly transmits measurement data together with information about its own location. This enables a receiving base station to identify the device by calculating its location. Moreover, this principle can also be applied for mobile devices.

Shared Data on InterBus

InterBus is a fieldbus system with cyclic operation making use of a total frame protocol. It is very well suited for real time applications. The additionally defined PCP (peripherals communication protocol) is designed for the exchange of numerous data without hard real time demands, eg. parameters and program downloads. “Shared Data” is a new approach presented in this paper which enhances the features of PCP. It offers a data channel on InterBus generally useable both for tasks similar to PCP and for temporary real time connections among a small number of partners. The shared data channel allows data transfers marked with specific transfer codes directing data to a predefined number of modules. An immediate read out of data of modules is possible as well as a transfer of multiple data within the same execution cycle.

Locating of objects with discontinuities, boundaries and intersections using a compact ultrasonic 3D sensor

High resolution ToF measurements from multiple ultrasonic transmitter/receiver pairs allow determination of distance and bearing of reflectors. By combining methods for solving the echo correspondence problem, in case of multiple reflectors, and avoiding outliers, typically occurring on object discontinuities, a high quality map of 3D reflection points is obtained. This information is suitable for 3D scene analysis making it possible to determine location, orientation and parameters of planes, cylinders and edges. The presented sensor herein is low in cost, compact in size, can operate under real-time constrains and is suitable for a wide range of applications. Experimental verification was performed in an office room with multiple reflectors. Two planes are in close proximity showing the performance of solving the echo correspondence problem and the reduction of outliers. Determination of the orientation of a cylinder and its parameters in 3D show the high accuracy of the proposed system.

Advanced ultrasound object detection in air by intensive use of side lobes of transducer radiation pattern

In this paper correlation techniques are discussed to extend the measurement range of an ultrasonic transducer to its side lobes. Broadband coded signals (linear chirps) are used to steer the transducerpsilas radiation pattern. The presented method allows to extend the angle range of the transducer beyond the main lobe for distance measurements and delivers additional information about the angle from the transmitter to the reflecting object.