Method to detect vehicles

0001The invention relates to a method for detecting located a monitoring area approaching vehicles in Preamble of claim 1 defined genus.

0002Such a process is preferably in Weckvorrichtungen used, serve autonomous systems for monitoring on grounds of fields and / or to secure Terrain areas against the ingress of objects, here To enable vehicles only (wake) when reasonably sure it is clear that such objects in emerge monitoring range and / or that it is in the emerging objects also to the surveillance-specific Objects and not to others. Here, the wake has with lowest possible false alarm rate be timely that the object is still within range of System is.

0003In a known method for the detection of pedestrians, the monitoring location a pass (DE 195 42 871 C1) used as the sensors, a geophone and a microphone and their Outputs signally suitable preprocessed. In are the pre-processed output signals of the microphone continuously for predetermined time pieces peaks or- impulse detected and preprocessed in the equally Output signals of the geophone are transients or pulses eliminated at those locations at which in same time pieces of the microphone output signal peaks or pulses occur. Add to this impulse by elimination adjusted time pieces of the geophone is a predetermined maximum number of the largest signal peaks or extracted pulses and by means of the extracted signal peaks or pulses the probability of a pedestrian detection rated.

0004In this method, by eliminating signatures in Geophonausgangssignal that in microphone output occur, such sound events, including remote air blasts, imposed in the detection, the air in the media generate sound pulses, which in turn in the ground inject and Geophonausgangssignal a similar signature cause as the steps of the pedestrian. The Detection reliability is increased by the fact that the Detection result no longer with a yes / no decision displayed, but in terms of its Warscheinlichkeit is evaluated, so that the operator due to the Degree of probability or confidence score of detection again the reliability of the detection result from this can include its own calculus.

0005The invention is based on the object, a method of Detection of vehicles of the aforementioned type with a high Probability of detection and low false alarm rate to create it by without interpretation or review a Surgeon manages, that is fully autonomous, and only a relatively simple signal processing requires, so that it in Unattended Weckvorrichtungen, the mass products a represent, can be used.

0006The object is the case of a method of the preamble Claim 1 given genus according to the invention by the Features in the characterizing part of claim 1 gelößt.

0007The inventive method has the advantage that by the Independence of the alarm stages each alarm stage simply with respect to the required time and frequency region, the realizing method and the scope for signal processing leaves. The utilization of different physics Alicher Features in the sensor signals for the detection in the various Alarm stages leads to a significant improvement in the Detection method with respect to its reliability Vehicle detection and robustness against interference and to a high functional reliability of having such Process-driven wake-up device. The in each Alarm stages processed signals from a single or be removed from a plurality of sensors. The exchange the sensors can be easily, so that the process is easy can be adapted to specific features of the application. The Link generated in each alarm stage slave wake-up signals to the actual detection or alarm signal, the so-called. Master alarm occurs, by simple heuristic Rules changed slightly and to the specificities of Application area can be adapted and beyond are easy to implement. According to the requirements with respect to the false alarm rate and the Detection probability based on the reasonable Effort can select the number of existing alarm stages free and various alarm stages are combined differently. Thus, a working according to the method waking device easily to the demands made in a specific field of application, both technically and financially be cut.

0008The link wake-up signals of the slave to the master alarm can, for example by series connection of the alarm stages done so that each slave alarm an alarm stage the subsequent alarm stage is activated and in the order last alarm stage creates the master alarm. This has the Advantage that initially only the stages with low Energy consumption can be switched on and the high- higher-value alarm stages with correspondingly larger Energy consumption only after making an on vehicles indicative preliminary enabled.

0009The individual alarm stages can also be operated in parallel are, therefore, be turned on simultaneously, and their Slave wake-up signals are linked, the linkage weighted according to the confidence measures of the individual slave wake-up signals takes place. This has the advantage that despite the low Signal / interference ratios large detection ranges possible are and the false alarm rate is kept low. additionally is an early wake-up possible.

0010Expedient embodiments of the inventive method with advantageous developments and events organized by Out The invention result from the additional claims.

0011The inventive method is based on a in the Drawing apparatus for performing the illustrated Process described below in greater detail. It shows the Drawing a block diagram of an invention by the Process working, responsive vehicle noise Wake-up device.

0012The shown in the drawing in block diagram Wake-up device is used to activate or wake autonomous Control systems of land areas with respect to the Intrusion or driving over by vehicles every kind, wherein the autonomous system a reconnaissance system for detecting of troop movements or a combat system, for example a Mine system, the destruction of all or selected vehicles can be.

0013The terrain expelled together with the autonomous system Wake-up device has a refreshes schematic antenna 10, the three arranged offset in a star shape by 120 ° to each other Antenna arms 11, 12 and 13 has. Each antenna arm 11 to 13 are three microphones 14 at a constant distance spaced from each other. In the star point of the three antenna arms 11 to 13 another microphone 14 is present.

0014A signal processing for processing and evaluation of Output signals of the microphones 14 and for generating a Wake-up signal, the so-called. Master alarm when with sufficient high level of security, a vehicle in the monitored zone is detected, is divided into three individual alarm stages 15, 16 and 17 divided, working independently and qualitatively different characteristics that significantly for Presence of vehicle noise are described in them extract and evaluate signals supplied and sufficient confidence of the extracted features a respectively Alarm, the so-called. Generate slave alarm. The slave wake-up signals be a the alarm stages 15 to 17 functionally connecting logic unit 18 which in turn the master alarm generated.

0015Linking the slave wake-up signals can in different ways done. In the simplest case be the alarm stages 15 to 17 through the link unit 18 connected in series, that is, the slave alarm signal of Alarm stage 15 is used to activate the alarm stage 16 and the Slave alarm signal the alarm stage 16 for activating the alarm stage 17 used. The slave alarm the last alarm stage 17 then the master alarm. The order of Activation of the alarm stages 15 to 17 can exchanged will. Advantage here is the alarm stage with the lowest energy consumption (here the alarm stage 15) first switched on and the subsequent stages with high higher quality signal processing and thus a much larger Energy consumption only be switched on when each of the previous alarm stage another preliminary decision in Toward the Warscheinlichkeit a vehicle detection has been taken.

0016By linking unit 18, the alarm stages can 15 to 17 are also connected in parallel, ie the slave wake-up signals of concurrent alarm stages 15 to 17 be in the linking unit 18 under their weight Confidence according to predefined rules interlinked and the master alarm is from the konfidenzgewichteten Link generated.

0017The alarm stage 15 is equipped with a single microphone 14 of acoustic antenna 10 is connected, the alarm stage 16 at least one antenna arm 11 to the on, 12, 13 arranged microphones 14 connected, in Embodiment to all three antenna arms 11 to 13, and the alarm stage 17 is provided with every microphone 14 of the acoustic Antenna 10.

0018More specifically, in the alarm stage 15 in two separate Signal processing channels 21, 22 two time-dependent created level signals by both Signal processing channels 21, 22, the amplified filtered microphone output, rectified and is integrated, wherein the first signal processing channel 21 tailored to the vehicle noise broadband Filtering in a bandpass filter 23 having a bandwidth corresponding to the Frequency range of vehicle noise with a good user / noise ratio (Signal Noise Ratio SNR) equal to (in briefly below the frequency range of vehicle noise called), and integration after rectification with a large time constant in the block 24 takes place while the amplified microphone output in the second Signal processing channel 22 is filtered broadband (Bandpass filter 25 having a large bandwidth, typically in the predictive events in the monitored area, such as pop, Wind gusts and. Like., Evoked narrow peaks are), and in Block 26 after rectification with a small time constant, is integrated. The large time constant corresponds to the Term evaluation FAST (F) and the low time constant corresponds time review IMPULSE (I) or shorter according to DIN IEC 651st The two-level signals are an analysis and Evaluation unit 27 supplied. Here is the second Level signal from the signal processing channel 22 Signal peaks (peaks) are analyzed and the confidence of the rated peak recognition. In the first level signal from the Signal processing channel 21, both the background level as well as the shares of vehicle noise and the estimated rated confidence of vehicle noise detection. The Behavior of the estimation filter used to estimate this with respect to its functioning, its adjusted Function parameters and decision thresholds by Confidences of peak detection and vehicle noise detection affected. is from the analysis and evaluation unit 27 Finally, with sufficient confidence the vehicle recognition the slave alarm signal output to the linking unit 18th

0019The two signal processing channels 21, 22 may alternatively also each separately to a respective microphone 14 of the acoustic Antenna 10 may be connected.

0020The second alarm stage 16 comprises three parallel Signal processing channels 31, 32, 33, which in a Analysis and evaluation unit 34 are merged. Each Signal processing channel 31, 32 and 33 is at the Microphones 14 of the antenna arm 12, 13 and 14 of acoustic antenna 10 is connected. In each Signal processing channel 31, 32 and 33, the amplified output signals of the microphones 14 by means of a Adder 35 adds up and using a bandpass 38 or 39 and 40 in the frequency range of vehicle noises filtered. In the analysis and evaluation unit 34, the Spectra of the digitized sum signals formed therein and narrowband signal components, so-called. lines detected and the Confidence of line detection determined. With sufficient Confidence generates the analysis and evaluation unit 34, the Slave alarm. A method of forming suitable for this purpose normalized spectra and extracting lines in the DE 30 35 757 C2. A method for determining the Confidence measure is shown in DE 195 42 871 C2. In a simplified embodiment of the second alarm stage 16 can one or two of the parallel signal processing channels 31 to 33 omitted so that the expenditure for the Signal processing reduced.

0021In the event that the microphone 14 of the acoustic antenna 10 not linear on three radially aligned Antenna arms 11, 12, 13 are arranged, but any spatial in an array are placed and any Signal processing channel 131, 132, 133 to a group of connected microphones 14, for example, each one third of the total number of microphones 14 comprises, as is done a summation of the coherent output signals of the Group associated microphones 14, to which each adder 35 or 36 and 37 is replaced by a so-called. beamformer in which the microphone output signals suitable phase and are then added.

0022Alternatively each or can also only a Signal processing channel 31-33 the alarm stage 16 only be connected to a microphone 14, in which case only the Adder 35-37 omitted.

0023In the third alarm stage 17, the outputs of all 14 mics the acoustic antenna 10 in the frequency domain filtered of vehicles, including a bandpass filter 41 with a narrow bandwidth in the frequency range of vehicle noises is provided. The thus filtered outputs digitized and fed to a so-called. beamformer 42 by appropriate time delay and summing the delayed, digitized signals receiving directions utmost sensitivity, so-called. beams preformed forms. In the Analysis and evaluation unit 43 is the maximum of Emfangspegels determined in the various preformed beams, and by the direction of the preformed beams with the maximum Emfangspegel is the incident direction of a vehicle noise and thus the bearing angle set to the vehicle. In the Analysis and evaluation unit 43 is now a Peilverfolgung performed and evaluated their confidence. at sufficient confidence is issued, the slave alarm. The and of the three analysis and evaluation units 27, 34 43 issued Slave wake-up signals are in Linking unit 18 in the manner described above linked together, and at the output of the logic unit 18 is the so-called. Master alarm removable, which for Activation of an autonomous monitoring or Control system can be used.