An automatic information transmission system for a mobile object, the system including a response unit arranged to be carried along with the mobile object, and an interrogation unit arranged to be disposed alongside the path of movement of the mobile object for movement of the response unit past the interrogation unit. The interrogation unit is arranged to emit a carrier signal at a first frequency and to receive a signal at a second frequency different from the first frequency. The response unit includes a memory for storing information relating to the mobile object, a signal generator connected to the memory for generating a signal at the second frequency and containing the stored information, a signal receiver for receiving the carrier signal at the first frequency emitted by the interrogation unit, an emitter connected to the signal generator for emitting the signal generated thereby, and an energy converter connected between the signal receiver and signal generator for deriving operating power for the generator from the carrier signal at the first frequency.

Programmable inductively coupled transponder

A system for passively sensing low frequency (5 Hz to 50 kHz) EM emanations from vehicles and classifying them on that basis. A temporal frequency response is computed for the sensed EM emanations. Harmonic, non-harmonic and temporal features are extracted from the response and used to classify the vehicle. In the preferred embodiment, the temporal frequency response is displayed as a time, frequency and intensity plot, from which a technician visually extracts these features. The features can then be used either to determine a "signature" for classifying the vehicle or to determine specific characteristics which, in turn, can be used to classify the vehicle. Alternately, the feature extraction and classification can be performed by an automated classifier.

Passive vehicle classification using low frequency electro-magnetic emanations

Time–frequency analysis based robust vehicle detection using seismic sensor

Identification of civilian vehicles is in increasing demand in military and homeland security applications such as surveillance and traffic monitoring. This paper presents a new algorithm to estimate the fundamental frequency of a car engine sound accurately. It also presents examples of the use of this frequency to identify and classify different civilian vehicles. Acoustic features, such as the tristimulus response introduced in music theory, are proposed as tools for the characterization of the timbre of the car engine sound. In addition we introduce a new generalized M-stimulus as a tool to distinguish special features in some car engines.

Spectral features for the classification of civilian vehicles using acoustic sensors

Population growth, continuing suburbanization, and higher labor-force-participation rates, combined with a virtual halt in new freeway construction, have led to rapid increases in traffic congestion in the U.S. This congestion is costly, for example, the cost of highway congestion in the Lose Angeles region is estimated to be $3.6 billion per year. Roughly half of this congestion is estimated to be caused by incidents, and 63% is on freeways. In the future, planners project that congestion will increase dramatically and that the proportion of delay on surface streets will increase, as congestion spreads. Automated freeways have been proposed as a solution to urban traffic congestion. Paper describes the staged development of automated urban freeways and then suggests a series of research topics related to the major policy issues of road capacity, air quality, noise, safety and liability, cost and equity, privacy, and organizational complexity. These difficult questions should be resolved before public acceptance for the technology is sought. Policy research on these matters should be carried out before or at the same time as the technology is being developed.

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Automating Urban Freeways: Policy Research Agenda

Many agencies, both governmental and private, in the highway transportation field need a system which would automatically identify motor vehicles. The basic concept of such a system requires a vehicle-mounted coded device, a transponder, that uniquely identifies that vehicle. As this vehicle comes within the range of a system interrogator installed along or on the highway, the code is read by this interrogator and the identification of the vehicle is obtained. The ideal transponder is passive and requires no power; has no effect on, and is not affected by the vehicle; does not require physical contact with the interrogator, and requires no action by the vehicle operator. Sensing at a distance (noncontact) involves the detection of some type of energy; either radiated or reflected from the object being monitored. Many different sensing techniques, including magnetic, infrared, optical, sonic, radioactive, radio frequency (RF) transmission, microwaves, have been surveyed, investigated, and analyzed to determine their applicability for an automatic vehicle identification (AVI) system. This analysis has concluded that a low-frequency induction system is presently the most appropriate method for use on the highway environment, Several diverse systems differing in design details have been constructed and tested, utilizing this basic technique. This paper describes the design of these systems as well as the methods that have been proposed and/or developed using the other sensing technologies.

H.R. Inhelder

Papers

Automatic vehicle identification systems—Methods of approach

H.R. Inhelder

Papers

Automatic vehicle identification systems&#8212;Methods of approach

Automatic vehicle identification systems—Methods of approach