CN100569569C - Be used for detecting automatically digital train system near the train of crossing - Google Patents
Be used for detecting automatically digital train system near the train of crossing Download PDFInfo
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- CN100569569C CN100569569C CNB2004800041203A CN200480004120A CN100569569C CN 100569569 C CN100569569 C CN 100569569C CN B2004800041203 A CNB2004800041203 A CN B2004800041203A CN 200480004120 A CN200480004120 A CN 200480004120A CN 100569569 C CN100569569 C CN 100569569C
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Abstract
A kind of system that is used for automatically detecting in the existence of the detection of the railroad track relevant (102) or monitor area train with the level crossing.Described system comprises transmitter (610) unit that sends detection signal.Described system also comprises the receptor (615) that receives detection signal.Acceptor unit (615) receives one or more signals.The treater (604) that is coupled to acceptor unit is set for the processing received signal, and determine to detect or monitor area in train or signal existence, do not exist or move.This treater (604) unit is set for and starts action when this treater (604) is determined the existence of train or one or more detection signals or do not existed.The present invention also comprises the method that is used for detecting automatically in the existence of the monitor area train relevant with the zone, level crossing.
Description
The application requires in the provisional application No.60/447 of submission on February 13rd, 2003,195 preceence.
Technical field
The present invention relates generally to the railroad crossing port system.More specifically, the present invention relates to a kind of existence of the surveyed area rolling stock that is used for detecting automatically railroad track and the system and method for motion, and relate to the control of level crossing system.
Background technology
Need a kind of train detection systems and method that is used for the level crossing, its be provided at abundant covering surveyed area, be not subjected to from approaching in the relevant surveyed area in the level crossing of external disturbance and The noise to train, pass, the static and accurate detection left.
Also need than the lower system of current available system cost.The railroad track that the monitoring of this system and method is relevant with the level crossing, and by only detect univocal detection signal determine train when in the surveyed area of level crossing, thereby whole possible echo, interfering signal and the noises of eliminating.
Summary of the invention
Native system is provided at the improvement of the transmission aspect of track-circuit signalling, the total harmonic wave that is sent to reduce on railroad track.Described system also is provided at the improvement of the processing aspect of the filtering of detection, received signal of received signal and received signal, thereby determines the existence and the characteristics of signals of the track-circuit signalling that received.These improvement have strengthened the ability that track circuit system is worked and detected existence, motion, position and the speed of train in noise and rugged environment are arranged.The others of native system provide the reducing of required interval between the frequency of operation of track circuit system, for the increase of the quantity of the frequency of operation that is fit in the frequency band that this system distributed and to the improved frequency management of the frequency of operation of railway track circuit equipment.The improvement of the design that is provided at track circuit detection equipment on the other hand of native system, cost, enforcement and method of operation aspect.
In one aspect of the invention, providing a kind of is used for detecting in the existence with rolling stock in pair of guide rails and the surveyed area at the railroad track of the impedance that surveyed area is discerned and/or the train detection systems of position.The impedance of the existence of rolling stock and position change track in the surveyed area.Described train detection systems comprises: first transmitter, it is connected to the guide rail of railroad track, to be used for sending first signal with predetermined amplitude and predetermined work frequency along guide rail.The receptor that is connected to guide rail receives first signal.Be coupled to the response of first data acquisition unit first signal that is sent and first signal that is received of first transmitter and receptor, to produce the first multiplexed analog signal of expression first signal that is sent and first signal that is received.First conv becomes the first multiplexed analog signal conversion corresponding to a plurality of first digital signals of first signal that is sent with first signal that is received.Treater responds first digital signal and handles first digital signal, to determine the frequency and the amplitude of first signal that is sent and first signal that is received.
In another aspect of this invention, provide a kind of and be used for detecting in the existence with rolling stock in pair of guide rails and the surveyed area and/or the train detection systems of position at the railroad track of the impedance that surveyed area is discerned.The impedance of the existence of rolling stock and/or position change track in the surveyed area.Described train detection systems comprises first transmitter, and it is connected to the guide rail of railroad track, to be used for sending first signal with predetermined amplitude and predetermined work frequency along guide rail.Second transmitter that is connected to the guide rail of railroad track sends the secondary signal with predetermined amplitude and different predetermined work frequency along guide rail.The receptor that is connected to guide rail receives first and second signals that sent.Be coupled to the response of first data acquisition unit first signal that is sent and first signal that is received of first transmitter and receptor, to produce the first multiplexed analog signal of expression first signal that is sent and first signal that is received.Be coupled to the response of second data acquisition unit secondary signal that is sent and the secondary signal that is received of second transmitter, to produce second multiplex signal of expression secondary signal that is sent and the secondary signal that is received.First conv becomes the first multiplexed analog signal conversion corresponding to a plurality of first digital signals of first signal that is sent with first signal that is received.Second conv becomes the second multiplexed analog signal conversion corresponding to a plurality of second digital signals of the secondary signal that is sent with the secondary signal that is received.Respond first digital signal processor processes, first digital signal of first digital signal, with the frequency of first signal determining to be received whether in first passband frequency range.Described first passband frequency range is the function of the frequency of first signal that sent.Respond second digital signal processor processes, second digital signal of second digital signal, with the frequency of the secondary signal determining to be received whether in second passband frequency range of contiguous first passband frequency range.Described second passband frequency range is the function of the frequency of the secondary signal that sent.Respond processor processing first digital signal of first digital signal, with the frequency and the amplitude of first signal determining to be sent and first signal that received, thus determine as work as first signal that received in first passband frequency range time near surveyed area in the impedances of indication of the existence of train and/or position.Also respond described processor processing second digital signal of second digital signal, with the amplitude of the secondary signal determining to be sent on the threshold values still under, the secondary signal that receives as working as is the indication of the existence of train in the surveyed area of island in the nearby pass frequency limit time.
In another aspect of this invention, provide a kind of and be used for detecting in the existence with rolling stock in pair of guide rails and the surveyed area and/or the method for position at the railroad track of the impedance that surveyed area is discerned.The impedance of the existence of rolling stock and/or position change track in the surveyed area.Described method comprises first signal that has predetermined amplitude and predetermined work frequency along the guide rail transmission.Described method also comprises first signal that reception is sent out along guide rail.Described method also comprises first analog signal that produces expression first signal that is sent and first signal that is received.Described method further comprises first analog signal conversion is become corresponding to a plurality of first digital signals of first signal that is sent with first signal that is received.Described method further comprises handles first digital signal, determining the frequency and the amplitude of first signal that is sent and first signal that is received, thereby determines as the impedances near the indication of the existence of train in the surveyed area and/or position.
Others of the present invention hereinafter and feature will be in part apparent, and will partly be pointed out hereinafter.
Description of drawings
Fig. 1 is the schematically illustrating of railway crossing checking system that is used for independent level crossing;
Fig. 2 is schematically illustrating of two vicinities and overlapping railway crossing checking system;
Fig. 3 is the exemplary illustration as the impedance of the railroad track of the function of the frequency of operation between distance and 80Hz and the 1000Hz;
Fig. 4 is used for the prior art railway of three representative type frequency of operations near the explanation of track circuit receiving system filter design-calculated;
Fig. 5 is to an aspect according to the invention, near the actv. filter design-calculated explanation of track circuit;
Fig. 6 is the demonstrative circuit design near track circuit and island track circuit system of combination.
Fig. 7 is the exemplary flow chart that explanation meets the method for the existence of surveyed area rolling stock one embodiment of the present of invention, that be used for detecting railroad track and/or position.
The specific embodiment
Appointed time before train arrives level crossing is in the cycle, existence and the motion of railway crossing warning by detecting train, and triggers the protection that the crossing is provided such as the crossing warning of bell, lamp, crossing gate arm.By send on the railroad track that signal detects that near the crossing train exists and towards/away from the motion of crossing.When the voltage that is sent is being uploaded sowing time as the train rail of transmission medium, detect the train existence by receiving the voltage that is sent.Determine train movement for determining to electric current and voltage that the impedance of the track of train is applied on the train rail by monitoring from the crossing.
Fig. 1 has illustrated the typical prior art level crossing track circuit (100) with independent railroad track (102), and described independent railroad track (102) comprises a pair of continuous rail track (104) and (106) and level crossing (108).For correct work, must be at from the existence of the train of the nearly track of any side joint (102) of level crossing (108) and motion and monitor railroad track in any side of level crossing (108).Frequency by external conditions and the detection signal by being applied to track (102) limit the level crossing system monitor area extreme length or effectively near distance.
The level crossing warning adopts two different track circuits to carry out train movement and exist and detects.By measuring voltage and electric current, and the impedance of the track between definite crossing and the train, detect motion at the approaching train of the distance of 7,500 feet of any side maximums of level crossing (108) near track circuit (128).Determine the distance of train near track circuit (128), and detect motion near train in orbital surveillance zone (132) and (134) from level crossing.Near rail system measuring voltage, electric current and impedance, and provide these data to outside crossing system, this crossing, outside system determines the speed of approaching train and determines that based on distance and speed train arrives the time of crossing.Are used to the existence of train, position and the time of advent provide the constant notice time of advent of intersection signal system.Usually need to be independent of train speed, train arrive before constant time of advent of at least two ten seconds.The required minor increment of the monitor area of any side of crossing is the function by the time of fire alarming of the maximum speed of the train of this rail portion and expectation.
Island track circuit (130) is measured the existence of train in " island ", and described " island " is the rail portion that approaches level crossing (108) most.About 100 to 400 feet of level crossing (108) is crossed on island (118) usually.Described island (118) provides guarantees the safety zone of crossing warning near train work island (118) or in island (118) time.See also U.S. Patent No. 4,581,700.
Fig. 1 further illustrates guide rail (106) and two attachment points (112A) on (104) and the transmitter (112B) (110) of the track (102) with side that is attached to level crossing (108).Away from the described transmitter in location between (108) 50 to 200 feet of the level crossings.Receptor (114) also has to away from the guide rail (106) of the track (102) of the opposite side of the level crossing (108) of transmitter (110) and two attachment points of (104).Also typically away from location receivers between (108) 50 to 200 feet of the level crossings.Distance between transmitter (110) and the receptor (114) is known as the island (118) with transtation mission circuit of setting up on the railroad track that is known as island track circuit (130).
One or both sides at guide rail are terminal branching device (120) and (124) away from the longer distance of level crossing (108), and it is respectively by (122A/122B) with (126A/126B) be connected to guide rail (106) and (104) of track (102).Shunt (120) and (124) are arranged at apart between level crossing (108) the 300-7500 foot.The setting of shunt is determined in the warning that provides at least two ten seconds based on the speed and the level crossing warning (100) of train to vehicle that utilizes level crossing (108) and pedestrian's needs.Terminal branching device (120) and (124) are carried out frequency tuning,, thereby set up track circuit (128) so that seem to frequency short circuit near track circuit (128).This is created on fixed monitor area (132) and (134) of any lateral confinement of crossing (108), detects the existence or the motion of train in this monitor area (132) and (134) near track circuit and system.Though dispensable, in some one type of prior art syringe, green phase with lead (112A) and (112B) will send on the track (102) near track signal (128) and island track signal (130).In other embodiments, independent transmitter (110) can send separate with island track signal (130) near track signal (128).In addition, in other embodiments, independent receptor (114) can receive separate with island track signal (130) near track signal (128).
Work in the frequency limit of 80-1000Hz near track circuit.Compare island track circuit (130), use lower frequency limit near track circuit (128).As will be discussed, because the distance of extending, lower frequency provides longer distance detecting ability, and the impedance of getting on the right track in described distance is linear as the function of distance.Propagate in the long distance (being known as approaching) of the track that stretches out from the crossing near track signal.Approaching by stopping in tuned shunts away from the end points place of crossing, provide on tuning frequency each near blocked impedance of part.The receptor monitoring receives voltage, and transmitter monitoring transmission electric current, and it is used to definite impedance near track circuit then.This system monitoring is near the variation of the voltage and current level of track circuit.When train movement enters approachingly, wheel shaft provides electricity along separate routes, impedance near track circuit that it changes as sees by checking system.The rate of change of this impedance and the speed of train are proportional, and the detection of motion of train is provided like this.Utilize this information, the time that train will be in crossing can be calculated by system.In some systems, can not rely on train speed and provide constant time of fire alarming for the motorist of crossing.
Island track circuit (130) is with higher frequency work, to detect the existence of train in short island monitor area (118).The representative type frequency of operation is in the 2kHz-20kHz scope.When train enters zone, island (118), the wheel shaft of train transmits the island signal along separate routes, so that the signal of avoiding being sent arrives receptor.In this operation, island track circuit (130) and checking system determine that train approaches level crossing (108) very much, and guarantee that warning works, and do not remove, and pass through the island until train.In other island track circuit system, the island track signal is included in continuously or the code that generates at random on (burst) basis of bursting.In these systems,, just trigger warning when one or more continuous codes can not be received by the receiver.As a kind of safety measure, typically make system invalid, for example send the signal of sounding all clear, until the continuous code that receives the correct reception of predetermined quantity.
Yet, in the prior art, have in the frequency spectrum that track circuit system adopted that to operate train detection systems in the best way in the situation of noise be difficult.Particularly optimum design needs to use the situation of lower frequency of operation because of needed surveillance distance.For example, have at track in the noise situations of near actv. 50Hz relevant with electrified track or the high power power line or 60Hz, because near the bad accuracy rate of checking system noise frequency uses lower frequency of operation so forbid track circuit.In addition, contiguous and overlapping track circuit system produces the design limit that the desired distance that is related to the measurement track selects to be fit to frequency best.
Fig. 2 has illustrated that the practical problems relevant with adjacent road is with relevant vicinity and overlapping orbitals Circuits System.In the left side of Fig. 2 is first track circuit system (100) relevant with first level crossing (108), and it is similar to described among top Fig. 1.First transmitter (110) and first receptor (114) define the first island monitor area (118).First shunt (120) and (124) limit first left side and first right side respectively near monitor area (132) and (134).
Similarly, distance first level crossing (108) is short-range is second level crossing (208).Second track circuit system (200) also goes up work at identical railroad track (102).Second transmitter (210) sends the island relevant with second track circuit (200) and near track-circuit signalling.Second transmitter (210) that combines with second receptor (214) defines the second island monitor area (218).In this case, second island (218) contiguous first island, but not overlapping with first island.Yet in operation, the distance between first level crossing (108) and second level crossing (208) causes probably near overlapping areas between the monitor area.Second shunt (220) and (224) limit a left side and right second respectively near monitor area (232) and (234).In this explanation, causing the overlapping distance location adjacent road of right first access areas (134) and left second access areas (232), thereby producing near overlapping (202).This is that the needed setting of second shunt (220) in the track circuit that is limited owing to first shunt (124) produces.Contiguous and overlapping must be not disturb or negatively not influence the frequency work of the operation of contiguous overlapping track circuit near track circuit system.Prior art systems need be used complicated and expensive analog band-pass filter, to distinguish between overlapping approaching frequency.In addition, vicinity is overlapping need select be designed to guarantee system's continuous working with frequency.It can not be best or expectation that frequency selects, this be since need for two systems to the suitable detection of train provide necessary near the track circuit distance so.Frequency select directly to relate to the transmission of track (102) or impedance operator and maximum speed train needs at frequency of operation near length.
Discuss as top, track circuit system sends signal in orbit, to detect the existing of train on the track, position and motion.Railroad track is to be used for various track circuit equipments, operator's compartment signaling equipment and the communication media that provides power supply that the electric power on the electric wire is provided to electrified locomotive is provided.In addition, track picks up the electromagnetic radiation from multiple source, the signal that described multiple source comprises immediate power lead, sent by adjacent tracks etc.So, the electric signal on the track comprises countless signal levels, frequency and harmonic content.
Fig. 3 is the diagram of explanation as impedance amplitude function, railroad track (102) of frequency and distance.The impedance operator of 28 (28) the individual typical frequencies that the prior art crossing track circuit system of working in 80Hz to 1000Hz frequency band of having illustrated Fig. 3 is adopted.The quantity limitation of frequency of operation is available total frequency bandwidth, detects the needed bandwidth of each frequency of operation and separate the function of needed bandwidth between frequency of operation.Thereby be similar to towards crossing motion at given frequency of operation dextrosinistral motion class on curve and reduce train near the surveillance distance of track circuit.When train during near level crossing (108), in shunt (120) or (124) before, the wheel shaft of train makes transmission along separate routes, and therefore reduces the length near track circuit.
The zone of slope linear each curve that reduces along with reducing of track length is the available tracks length at given frequency, so that detect train movement and/or position effectively.At the available of given frequency is the zone in peak line (314) left side near length.Cause maximum usable length or " peak value " on the impedance curve at the impedance operator of the track of each frequency of operation.Greater than the distance in the place that peak value occurs (as by peak line (314) right side regional represented), impedance curve change slope, and impedance reduces along with the increase of track length, reaches the constant impedance level that does not rely on distance until impedance.In this, track is revealed as the transmission line with constant or intrinsic impedance.When checking system measure impedance over time (increase or reduce) with motion, direct of travel and the train of determining train apart from level crossing apart from the time, the track length relevant with peak value is the maximum track length that train detection systems can be worked on given frequency.This needs impedance is linear as the function of distance in essence.Because impedance reduces no longer linearly when train moves towards the crossing, cause system can not detect train movement to the distance on peak curve (314) right side.Only being designed to is just providing correct detection to train movement less than the distance of Impedance Peak distance with the system of selected frequency of operation work.
Fig. 3 also illustrated when when the peak value of lower frequency appears in big distance for long orbital surveillance distance lower frequency be best.Yet, because higher frequency causes the higher impedances level of accuracy rate detection that can be bigger, and provides the bigger variation of per unit apart from impedance, so higher frequency provides the more accurate means that detect train.Usually, the specific frequency of operation near track circuit is chosen as the highest frequency that can allow to drive given track length.For example, for the track with required maximum detection range, the impedance line (302) at the frequency of operation place of 86Hz causes amounting to the peak value of locating just over 7000 feet maximum operating distance (304).Yet the resistance value of guide rail is less than 1.15 ohm, and when distance reduced, the variation of the resistance value between 7000 feet to 2000 feet caused 0.55 ohm reduction, and this only is per 1000 feet 0.11 ohm variation.By contrast, as higher operational frequency place by the illustrated about 565Hz of curve (318), it is to produce 3000 feet of 2.65 ohmages that peak value detects distance.It is reducing of three multiplications big 0.3 ohm that for this frequency of operation 1000 feet to 2000 feet reduce causes aspect sensitivity.This further specifies by the curve (328) at the frequency of operation place of 979Hz, and this curve has 4.0 ohm peak impedance at 2000 feet places.The impedance of the track at 979Hz place drops to 1000 feet and locates 2.8 ohm, to be used for per 1000 feet 1.2 ohm sensitivity.The sensitivity of described increase provides to be determined the improved of the position of the train of advancing along track (102) and speed.It may be noted that Fig. 3 has illustrated an embodiment as the impedances of the function of frequency and distance.Yet owing to other external factor, such as rail material, working condition, track condition and ballast aggregate situation, the relation of impedances and length and frequency will change.
The railroad grade crossing panalarm has the restriction about the level that can be present in the electrical noise in the working environment, to allow system's reliable operation.Discuss as top, track comprises the noise from many sources.In fact, some rail portion comprise enough influential so that the sources of electronic noise of unaccommodated transmission environment for the reliable operation of railway crossing checking system to be provided.Example be have electrified guide rail, for example deliver DC or AC electric power with rail operations to the guide rail of the train power supply of on guide rail, working in.Electrified guide rail usually charges with the AC power of 50Hz or 60Hz.Work in this situation of lower frequency in prior art system, for train being existed and motion is carried out accurately determining, described system can not carry out filtering to the track-circuit signalling from necessity of electrified power signal and relevant harmonic wave and noise.Do not have the ability that AC power noise signal and relevant harmonic wave are carried out abundant filtering, receiving system can not detect the track-circuit signalling that is sent fully.
In addition, parasitism (stray) electronic signal from contiguous crossing or contiguous railroad track not inadvertently infilters in (bleed over into) railroad track by the leakage in the ballast aggregate.The sort signal leakage can negatively influence the work of level crossing system.Because leakage and overlapping near track circuit needs railway to replace the frequency of operation of managing various systems by the selection that makes frequency of operation between contiguous crossing or the contiguous road track.This frequency management need select not only to have suitable orbital distance ability and also based on be used for analog band-pass filter to each frequency filter capacity and have the frequency of operation of necessary bandwidth granularity.Selecting the purpose of frequency is to reduce the possibility that leakage signal influences neighbor systems.In identical railway worker design and operate that this usually is manageable in the situation of whole adjacent tracks, but, really can become the problem of management by other railway worker design with have in the situation of adjacent tracks.
In one embodiment of the invention, active phase place cancellation noise reduces to provide the reception noise that reduces from being present in the signal on the railroad track, and this is particularly useful for from the outside superpower circuit such as 60Hz or 50Hz electric wireline and removes the track circuit noise.By utilizing active phase place to eliminate, bandpass filter is tuned to the frequency of interfering signal.Filtered noise signal displacement 180 degree, and be added back in the source signal.This causes eliminating the phase shift noise of the noise that is present in the source signal, thereby eliminates the interference from signal.This has improved the sensitivity of receptor, thereby has improved determining of received signal, also produces the cleaner signal that causes improved signal detection.
Typically, bandpass filter is used to recover the signal that signal and blocking-up at interested frequency place have undesired frequency.The operating characteristic of bandpass filter comprises the bandwidth of bandwidth, the stopband (for example (458), (460), (462)) of passband (for example (410), (420), (430)), usually is restricted to the percentum of the energy of " acutance " of filter of slope of transitional region (transition region) and the frequency outside the stopband effectively blocked.The signal of working in passband is typically by 100% of signal, for example unattenuated signal.As shown in Figure 4, from (404) to (406) illustrate the passband of analog filter (410), and relevant stopband (458) is the frequency of locating to (448) from the frequency of (446).For the analog filter that illustrates, the signal at the frequency place outside stopband is the 0.1%-0.01% by signal only, or the 99.9%-99.99% of deamplification.Analog filter has the wide frequency band between passband and stopband.This frequency limit is known as transitional region, is represented as line (444) and line (416) as an example of the filter among Fig. 4 (410).Based on the transitional region slope of a curve, the signal that has the frequency in the transitional region by the decay of various level.The transitional region many or desirable more in the signal attenuation of characteristic frequency place is more little, then needs bigger and more complicated analog filter, therefore needs more parts and cost to increase.
Because analog band-pass filter is enough " precipitous " not, for example the slope of transitional region is not rapid take-off and landing like that as required, thereby can not be signal attenuation with the frequency outside the passband to expecting level, so may not enough actvies during in the next track circuit frequency of blocking-up at the bandpass filter at a certain tracks channel frequency place.The shortage of acutance produces the action need to a plurality of working track channel frequencys that are used to comprise the compatible situation of contiguous crossing work in the analog filter.In addition, in high-noise environment, the signal attenuation in stopband or transitional region may be not enough to allow prior art systems accurately to work with needed track circuit frequency.
The railroad crossing port system of prior art adopts analog band-pass filter, so that interested frequency is passed through, blocks the frequency that other received simultaneously.In manufacturing process, typically these analog band-pass filters are tuned to the configuration that is based upon specific railroad grade crossing system and the frequency of operation of design-calculated frequency of operation.In nearer prior art, researched and developed the programmable analog band-pass filter, wherein in by the working process of software control, can change the frequency response of filter.Cascade multilevel simulation filter typically is to provide the noise suppression of increase.In any situation, because tolerance variation, temperature traverse and the sum of errors introduced by analog band-pass filter are because the error mismatch that cascaded stages causes.
Traditional railroad grade crossing panalarm is the rejection characteristic of analog filter in the restriction aspect the immunity to a distrubance of electrical noise.Shown in (465) in passing through Fig. 4, the typical threshold that is used for noise immunity in the prior art systems is 1% of a signal of interest.The signal level of frequency-of-interest 1% on any signal or will influence the ability that warning is predicted train movement exactly unfriendly with any frequency of the intra-zone of the crossing filter response of 1% noise immunity line (having the intensity identical or bigger) with interested signal.Such as discussed, the characteristic of train detection systems that adopts analog filter is in high-noise environment and not ideal in the environment that needs a plurality of frequencies owing to the frequency of operation space requirements.
Digital filter is a programmable, and can easily be changed and do not influence circuit (hardware).In one embodiment, provide filtering like this, so that implement filtering by software by digital signal processor.Compare with the analog band-pass filter of prior art, this embodiment saves cost and board space (board space).Be not subjected to the fluctuation or the influence of temperature variation of component tolerance according to digital filter of the present invention.Realize that with respect to utilizing analog filtering the performance of digital filter of the cost of this function provides the obvious improvement to prior art.Therefore digital filter provides improved acutance in the transitional region, and provides the signal at the frequency place outside passband than more manying decay from the analog filter of reality is obtainable.For example, be possible near the inhibition of the increase of the frequency the target frequency, thereby allow previous unaccommodated near by frequency can be used to independent enforcement.This cause to provide improve operation, with may the suppressing of the required bandwidth of crossing system works of the frequency interference that reduces of other operating system and easy frequency coordination and management.Improved filter also allows with design of the frequency interval that reduces between the frequency of operation and operating system, and allows more approaching interval design and realization system with near by frequency.In have a plurality of vicinities and/or overlapping situation owing to high-speed and a plurality of track circuits of work train closely approaching near track circuit, this is a particular importance, the quantity that adopt to increase ideally with track circuit such as the lower frequency work in 80Hz to 150Hz operating frequency range.
In one embodiment, native system has digital signal processor (DSP), described digital signal processor adopts finite impulse response (FIR) (FIR) or infinite impulse response (FIR) digital filter, with The noise outside the restricted band with to the interference of signal measurement.For the abundant inhibition in the stopband the filter coefficient that precipitous transitional region between the frequency from filter passband to stopband and right quantity are provided, the DSP filter adopts many speed technology, carries out filtering so that allow with the sampling frequency that is lower than data sampling rate.The convolution of the impulse response by the source signal sampling and the filter that will adopt realizes finite impulse response filter.The sampling of filter impulse response is called as filter coefficient.This filter of design makes to make the transitional region steepen when the inhibition of increase stopband, when reducing passband fluctuation and when the sampling frequency of source signal increases like this.In these situations, the quantity of filter coefficient increases.Needed more filter coefficient has increased needed storage and processing time.In addition, data are overflowed the distortion that may cause signal with quantization effect.On the other hand, the accuracy rate of determining the amplitude of source signal depends primarily on the sampling to the two-forty in source, has increased the quantity of needed filter coefficient like this.For the needs of these two contradictions of balance, an embodiment provides the multirate filter design.In this embodiment, with high sampling rate sampling source signal, and extract 1/10th of this source signal, thereby reduce sampling frequency effectively by only keeping every n sampling.Finite impulse response filter has reduced the quantity of needed filter coefficient with this lower sampling frequency running.At the output of filter, the factor by N carries out interpolation to filtering data, thereby recovers original high sampling rate.At last, interpolative data is carried out the inverse video finite impulse response (FIR), to eliminate the spectral image of interpolation frequency.Because the inverse video filter has than the more undemanding needs of master data filter, it needs few relatively coefficient.Net result is unusual special quality finite impulse response filter, its can with than needed coefficient under the situation of not utilizing the speed of manying technology significantly few coefficient on data, turn round.
The filtering that another embodiment of the present invention adopts not fluctuation in time or changes, or as the result's of the variation of temperature or operating voltage filtering.For example, the software filtering of the attenuation characteristic that conforms to the working condition of not relying on is adopted in the filtering that provides by the digital signal processor (DSP) that meets this system.
Another embodiment provides over-sampling, filtering, signal averaging with relevant, with higher accuracy that received signal is provided and the bigger confidence level that is used for the data that exist and move of definite crossing monitor area train.
Another embodiment of native system uses relevant programme, to recover modulation signal from comprise the environment from the noise or signal that is close to the railroad grade crossing warning.By the crosscorrelation of received signal, reduce noise or other undesired signal with respect to interested signal, thereby increase signal to noise ratio with the signal that is sent.
Another enforcement of native system is the filter correlation technique of using coupling, with the maximization signal to noise ratio, and therefore provides the bigger accuracy rate of the amplitude of the signal that is recovered.
Another embodiment of the present invention is to carry out over-sampling to received signal, increasing signal to noise ratio, and provides the bigger accuracy rate of the signal that is recovered.Signal is carried out over-sampling also allow as the signal that suppress to surpass Nyquist frequency is required needs outside antialiasing (anti-alias) filter.This provides the improvement at the design aspect of antialiasing filter, and cause need be lower cost.
Another embodiment of the present invention is used signal averaging, so as coherent signal and increase along with the number of times of the measurement of being carried out, noise only increases as the square root of the number of times of measuring simultaneously.This provides the signal to noise ratio that increases.
Another embodiment of native system provides the gate of receptor to receive, so that corresponding to the cycle that sends the island signal with from only receiving the island signal that is received by transmitter during the gate window (gated window) of the needed time cycle of transmission of receptor.Image duration when the island signal is sent out, so that only receive the island signal, reduced to respond improperly the probability of different island circuit transmitters by gate island signal receiver.
Another embodiment of native system uses and replaces random frequency to be embedded in code word and cycle count in the track signal, with identification signal uniquely.By modulation scheme, selected code word is modulated on the signal that is sent to track such as Quadrature Phase Shift Keying.The signal that demodulation receives from track, and check the existence of embedded code word.If find one, then it and the code word that is stored on the transmitting element are compared.If code word does not match, then suppress this incoming signal.By certainty ground distinguishing signal, rather than depend on that ccasual is relevant, this has improved existing setting.In addition, the ability that code word is set on track signal allows a crossing control unit transmission information to give adjacent unit, to be used for the alarm of state or train on the horizon.
Referring now to Fig. 4, analog band-pass filter passes through the frequency in the limited range of any side of frequency of operation.Make the frequency spectrum of the bandpass filter that 100% signal passes through be known as the passband of filter.Fig. 4 has illustrated three representative type frequency of operation: 86Hz (402), 114Hz (418) and the 135Hz (428) of railroad grade crossing track circuit.First analog band-pass filter (410) detects the track-circuit signalling of the 86Hz of low side (404) with passband and high-end (406).Passband (410) is centered in central task frequency (402), and 100% of all frequencies between (404) and (406) are passed through.An example is the 86Hz filter with 16Hz passband, and it makes and will be (404) of 78Hz and will pass through for 100% of all frequencies between 96Hz (406).The bandpass filter that manufacturing has very narrow transitional region is difficult, and very expensive.Yet, expectation adopt have enough narrow with only make desired frequency 100% by decay the fully filter of transitional region of all other frequencies of, while.Be equipped with the train detection systems of this narrow bandpass filter that improved train detection will be provided, and will allow to approach greatly the use of the frequency of operation of other frequency of operation.This is particularly in high-noise environment or the situation when having a large amount of other track circuit.
Analog filter is not perfect filter, and the signal outside passband of similarly can not decaying 100%.This illustrates by the forward position (444) of filter (410) and the slope on edge, back (408) in Fig. 4.Forward position (444) and back are along at least 99.9% of the signal of (408) frequency of fadings outside stopband (458).Yet, when frequency is in the transitional region that approaches passband, the percentum of the increase of signal level is passed through.The zone of the filter curve that the percentum of the signal that passes through reduces is known as transitional region " decline " (roll off).Directly influence the ability of receiving filter inhibition as acutance near the frequency of band connection frequency by transitional region as described in the slope of a curve reflection.The transitional region that the analog filter that uses in the prior art train detection systems has every decimal scale frequency (per decade of frequency) 20-100db descends.Decline Shaoxing opera is strong, and needed analog filter is just big more and expensive more.This is based on cost and PC board space need be to the physical constraints of the size of these analog filters.
The circumscribed influence of analog band-pass filter plays negative consequence to the ability that receives and detect desired frequency of operation and received signal characteristic.Therefore analog filter limitations negatively influences train detection systems and determines impedance and the ability of therefore determining existence, motion and the speed of train.Analog filter limitations also negatively influences the ability of using a plurality of frequency of operations in desired frequency spectrums of operation.
Referring again to Fig. 4, locate to illustrate the second frequency of operation 114Hz now in (418).Second analog filter (420) has the passband from (422) to (424).The passband of second filter (420) is different from the passband of first filter (410), and is spaced apart frequency band (412) and separates, to provide the only detection of the frequency in the passband of desired filter.Yet, because each analog filter all is faulty, and make with outside the passband and as the transitional region that limited of the forward position (414) of back edge (408) by first filter (410) and second filter (420) in the signal of frequency work pass through, separation band is enough big in some cases to decay fully and to be close to the relevant frequency of bandpass filter.
Because the limitation of the frequency of analog filter decay outside their passband is usually selected the frequency of operation that is fit to.Adjacent analog filters provides separation band (412), so that lower neighbor filter only makes and the predetermined tolerance levels of the signal of the frequency dependence that the upper frequency filter of vicinity is overlapping is passed through.In described explanation, be shown overlapping the intersecting of representative type at 10% level place by point (416).In this example, with the system of 86Hz bandpass filter work tolerance frequency (422) (its be 114Hz filter than the lower passband frequency) is located 10% of signal and pass through.Because 1% noise threshold, overlapping with at the 86Hz place not that this means in the work of 114Hz place near the track circuit compatibility near track circuit.As a result, needs are used next higher or lower frequency.What operating system need be close to that the working track circuit do not have its filter passband and a contiguous working track circuit surpasses the overlapping of 1% noise threshold.Equally, in the vicinity identical, can not adopt the frequency of operation (402) of filter (410) with frequency of operation (420).The next frequency of operation compatible with frequency (402) will be the frequency of operation (428) of bandpass filter (430), and described bandpass filter has the passband from (432) to (434).In this case, the transition band (436) of filter (430) intersects with filter (410) passband (406) that is lower than 1% noise threshold as can be seen.Yet when it can not provide in this zone maximum speed train surveillance distance needed necessity or desired, the employing of frequency of operation (428) may not be the optimal selection that is used to dispose.
Native system adopts digital signal processing (DSP) system, so that being provided, narrower filter passband and more precipitous transition band descend, and the improved filtering system that outside passband, has improved decay.As shown in Figure 5, first filter (510) that meets native system has as the forward position (544) by transitional region and back along the obvious improved decay outside the shown passband of slope of the increase of (508).Utilize analog band-pass filter in fact can not obtain attenuation characteristic outside as shown in Figure 5 the passband.The decay that increases in these transitional regions provides the work of train and the improvement of detection.
Additional improvement provides the signal to noise ratio to the increase of the signal of signal detection system.By having the strong signal of higher signal to noise ratio in the frequency that passband is provided, obviously improved the detection of characteristics of signals.Described checking system has cleaner signal, with the voltage and current of analysis and definite operation signal that is sent, and therefore determines impedance.Another improvement of native system is, owing to the slope of decaying in the transitional region increases, so can reduce the separation band between the frequency of operation.As shown in Figure 5, overlapping level between first filter (510) that occurs under 1% the noise threshold level that illustrates by (565) as illustrate and second filter (520) by point (516).
The filter design that meets native system provides reducing as the bandwidth result, required separation band that improves acutance in the transitional region.So, can use than the more approaching frequency of operation that before can use.In addition, this make near by frequency can be used for overlapping near on, wherein previous they be unaccommodated.As shown in Figure 5, because the slope of transitional region increases, can reduce two intervals between the filter.For example, the separation band between filter (510) and the filter (520) is current has illustrated to sentencing at point (517)＜passband of the transitional region that 0.1% signal percent of pass intersects.Because therefore this intersecting under 1% noise threshold level this means to reduce separation band (512), and can reduce frequency of operation (418), for example can adopt more the frequency of the frequency that approaches (402).As shown in Figure 3, in the working band of 80Hz to 1000Hz, most of owing to the restriction to analog filter, prior art is restricted to 28 frequency of operations.On the contrary, native system will provide the reducing of required bandwidth of separation band.This will cause the increase of the quantity of usable frequency individually.
Another operations improvement of the present invention is the improvement of filter aspect, with provide to noise and interference, particularly with decay in the increase of the relevant noise or signal of the power supply of 50Hz or the work of 60Hz place.By the improved filtering to these powers signal is provided, now can be not useable for so far near the abominable electric of track circuit system or. in the noisy environments near track circuit on configuration adopt the track circuit of low frequency of operation and therefore long track length.This comprises the configuration to electrified rail system.
Another operations improvement that meets native system is the reducing of bandwidth of filter passband.As discussed above, analog filter the independent frequency of its filtering, and therefore make between high-end frequency and the low side frequency frequency by, and therefore to limit aspect the ability of passband be limited.An embodiment of native system provides and detects obviously reducing of the required passband of transmission frequency.Referring again to Fig. 5, passband (510) is centered in frequency of operation (402) now.One embodiment of the present of invention are provided at the bandwidth aspect than passband (510) relevant with frequency of operation (402), that required passband as shown in Figure 4 is narrower, for example passband (410).Prior art systems as shown in Figure 4 need be 10% the passband such as (410) of the plus or minus of frequency of operation.For example, be 86Hz at frequency of operation, total passband is approximately 16Hz, and it is from 78Hz to 94Hz, for example plus or minus 8Hz.On the contrary, in one embodiment of the invention, passband be reduced to frequency of operation plus or minus 3%.In such an embodiment, the passband of 86Hz frequency of operation (410) will be from 83Hz to 89Hz, and the required bandwidth of the passband of filter obviously reduces.This itself provides the essential improvement to signal to noise ratio, analyzes this signal to noise ratio to determine the work transport property.
According to another of one aspect of the present invention improve by the reducing of pass band width and required interval bandwidth, for example relevant filter stop band (for example (553), (560), (562)) reducing of bandwidth and produce.By reducing the stopband relevant with each filter, obviously more approaching frequency becomes now and is suitable for neighbor systems mutually.Referring again to Fig. 5, the intersecting of the last passband (506) of the frequency of occurrences under 1% noise threshold (402) and the transition zone (514) of frequency (418).So, can adopt frequency of operation less than frequency (418), and this frequency of operation still is suitable for adopting the track circuit of frequency (40) as frequency of operation, even and in the prior art frequency (418) also not with overlapping near in frequency (402) compatibility.
By reducing the bandwidth of passband, checking system is equipped with narrower frequency limit and has the cleaner signal of less noise, determines characteristics of signals from this signal.Narrower signal comprises less noise, and has improved the detection of signal.This causes the ability of operation train detection systems in harsh environment, and described harsh environment comprises other signal, sizable noise and harmonic wave.Because narrower passband filtering, before being offered checking system, signal just more effectively decays from the noise of power-supply system, electrified system, operator's compartment signaling system and vicinity and overlapping track circuit system.
Another operations improvement that is produced by the pass band width that reduces of receiving filter is the ability that adopts more approaching mutually frequency of operation.In one embodiment, because the pass band width of the prior art of 16Hz is to 50% reduce of 8Hz, the quantity of available frequency of operation increases to 42, promptly 50% increase between 80Hz and the 1000Hz from 28 frequency of operations.The operations improvement of native system is the increase of the quantity of usable frequency, described frequency be can carry out for the concrete selection of the frequency of Yan Gengjia near orbital distance and maximum train speed.For example, native system provide allow longer frequency spectrum near length than the more multiplex (MUX) working frequency in the low side.In addition, because the improvement aspect other signal of attenuation ratio such as 50Hz or 60Hz power supply signal, the frequency that is lower than 80Hz can be used as frequency of operation now.By adopting the frequency less than 80Hz, as described in Figure 3, longer is possible near track length.When train worker design have the train speed of increase, need be than longer system near length before the time, this is especially desirable.
In addition, the improvement of native system provide when contiguous and/or overlapping track circuit can " be used " more frequently again and than prior art frequency of operation more closely near the time needed frequency the reducing of total amount.
By reducing to be introduced by track circuit transmitter (110) total harmonic distortion of railroad track (102), native system provides the obvious improvement of the operating characteristic of track circuit transmission system.As discussing about noise, comprise appreciiable noise in the above as the track of transmission medium.In the described noise some are actually by the generation of the signal that comprises many harmonic waves, amplification and transmission and are produced by prior art track circuit transmission system.In fact, the system that sends signal in orbit that comprises the operator's compartment signaling system of level crossing system and coding causes most reason in this harmonic noise content.The prior art track circuit system produces sizable harmonic content.Because feasible system self signal that is difficult to recover to cause insecure operation or coarse time of fire alarming of the significant level of the noise that harmonic wave produced.In some cases, because noise jamming can not operate the crossing panalarm with other track equipment, or vice versa.
The track transmitter of prior art produces square-wave signal, by analog filter described square-wave signal is carried out filtering to remove higher frequency harmonics.Therefore yet because analog filter is being removed harmonic wave fully and produced limitation aspect the pure wave signal, the filtered signal of near sinusoidal ripple comprises many harmonic waves.The filtered signal that comprises many harmonic waves is provided for amplifier, sends in orbit being used for.Utilize digital signal processor, the invention provides generation from the high fidelity sinusoidal waveform that has harmonic wave hardly of sine wave generator.In one embodiment, the total harmonic distortion of native system (THD) is less than 1% of all frequencies between 80Hz and the 1000Hz.By the high fidelity signal that utilizes digital signal processor to produce to be exaggerated subsequently and send in orbit, the track transmission system has the relevant minimal noise of harmonic wave with the frequency of operation of track-circuit signalling.In one embodiment, digital signal processor changes sine wave generator circuit wheel by the table of sinusoidal wave number with assigned rate, to be created in the high fidelity sinusoidal signal at desired frequency place.Other embodiment that is used to produce pure wave with minimum distortion comprise sinusoidal waveform calculate, from the sinusoidal waveform of ROM search, the filtering and the interpolation of Direct Digital synthetic (DDS) and recurrence.Amplify resulting sine wave signal by low distortion power amplifier, and it is applied to the track with considerably less harmonic content.This solution allows level crossing equipment easily to detect and recover its transmission signal, thereby causes the reliability that improves and better accuracy rate.By not producing the interference harmonic frequency, it also allows the track equipment compatibility of crossing panalarm and relative broad range.
In another embodiment of native system, system provide near and the improved control of island track circuit gain, allow in the operating process of system because outside and environmental factor and real-time regulated is carried out in gain.When in the starter system setting up procedure typically the calibration or definite track on sent the voltage and current level time, the working environment of track circuit equipment is abominable, usually experience the significant change of operating temperature and situation, comprise the impedance of snow, ice, rain and salt pair track and the influence of the leakage that occurs from adjacent tracks.In the course of the work, native system provides automatic gain-adjusted, guaranteeing the transmission level continuous working of system with the best, and makes impedance curve and receive data analysis and be fit to.
Native system provides track circuit frequency management and is used for the improvement greatly of method of operation of design, enforcement and the work of track circuit system.This frequency of operation configuration not interfering with each other for contiguous crossing is critical.For the alerting ability of the maximum that obtains to dispose, railway need have the crossing protection system of selectable extensive work frequency.As top the argumentation, native system provides the increase of the quantity of available work frequency in the working band of 80Hz to 1000Hz.In fact, because the reducing of the bandwidth of passband and separation band, the quantity of the available work frequency that provides by native system will increase.In addition, native system provides the employing of the frequency that is lower than previous employed frequency, and this has not only increased the quantity of frequency of operation, and has increased the ultimate range that can be used near track circuit.Prior art systems can utilize and the quantitative aspects of the frequency of operation that is fit to, particularly aspect the extremely long lower frequency required in the restricted situation near length, native system increase of frequency of operation and the frequency of operation that is fit in lower frequency ranges has improved the design of track circuit, thereby allow to be used for best more designs of certain tracks and train speed and to the less dependence of external factor, described external factor is such as being adjacent signal and overlapping system.Can utilize long approaching distance to realize more track circuit now, this allows the more crossing protection of the train of rapid movement.
Referring again to Fig. 2, in having the metropolitan area in many streets, it is overlapping track circuit to occur now.In these situations, or near the zone that just is near at hand in the situation of (perhaps on identical guide rail, perhaps on the adjacent rail in two or tritrack), each crossing must be near track circuit with the frequency work of different compatibilities.As discussed previously, the availability of Jian Rong frequency is subjected to acceptor circuit that suitable frequency is limited by the ability that suppresses undesired frequency simultaneously.In utilizing the certain situation of prior art systems, frequency of operation to need to select system designer to select frequency less than frequency best concerning required track situation or required track circuit surveillance distance.This part incompatibility has produced in the prior art needs to a plurality of frequency of operations between the desired frequency of operation of 80Hz and 1000Hz.Reflect that as Fig. 3 some prior art systems have 28 frequency of operations defined in the frequency band of 80Hz to 1000Hz, so that produce the combination of the abundant compatibility that is used for maximum work railway systems.Yet in the high situation of train speed, when only having lower frequency that the track length of growing of necessity is provided, the total quantity of compatible frequency is significantly less than 28.
No matter be close to, in the overlapping or multi-orbit situation, the improved filtering of native system and detectability will reduce needed frequency coordination between the various track circuits significantly.When reducing the variation of frequency of operation, the increase of quantity that surpasses the frequency of operation of total work frequency band will reduce being used to stop the needs near the tuned shunts of track circuit.
System according to one embodiment of the present of invention provides best definite with the system of the island track circuit frequency that is used for concrete operations enforcement near track circuit.This system is based on the automatic analysis that is sent to the test signal on the work railroad track being selected best frequency of operation, described test signal comprises noise and from the transmission signal of outside source, described outside source comprises power lead and other contiguous and/or overlapping track circuit equipment.Described system determines optimum working frequency (OWF) function, that be used for needed detection distance as the quality of received signal according to noise and operating characteristic.As mentioned above, definite frequency is not limited to preset frequency or passage, but selects the frequency of operation of unlimited amount in frequency band.
In examples of implementation, native system is determined the threshold values of recover and the quantity of the island burst signal of being confirmed automatically, and described signal determines whether the island to be claimed as active or passive.Determine threshold values based on system analysis, to be used for as according to implementing as the noise of the track of transmission medium and the concrete track circuit of function transport property, quality of signals to the test waveform that sent in orbit.
Similarly, in another embodiment, system be provided for regulating time between the continuous island signal bursts, recover and the determining automatically of the threshold values of the quantity of the island burst signal confirmed, thereby optimization system enters or leaves the response time on island to train.
In another embodiment, in the starter system implementation process, provide the automatic calibration of approaching and island track circuit, so that at concrete track situation optimization transmitted power.This system produces and is used for the island track signal or near track signal or both test tracks circuit signals, and analysis received signal, with the optimization signal to noise ratio,, and can determine the existence and the motion of train best so that make receptor detection of transmitted signals best.This has improved the operation of system, and has reduced design and the time is set.In addition, system provides in operating process the meticulous tuning adjusting to horsepower output, be provided at received signal quality consistent during the system life to be independent of the variation that is caused by external factor, described external factor is such as being weather, noise, temperature, ballast aggregate situation and such as the existence of the foreign matter of ice, snow or salt.
Referring now to Fig. 6, the system schematic of an embodiment of track circuit (600) comprises near track circuit (602) (for example 128) and island track circuit (650) ((110) for example have been described).An embodiment adopts double digital signal processor (DSP).First digital signal processor (DSP A) (604) provides sine wave signal output (626) to sine wave generator (606), be produced as pure wave with minimum harmonic content near sinusoidal waveform (608).The one DSP (604) provides near gain signal (624), describedly provides the gain control near necessity of transmitter (610) near gain signal.Be provided near transmitter (610) near sinusoidal waveform (608), should be near transmitter (610) based on amplifying near sine wave signal (608) near gain signal (624), and by transmitter leads (112A) and approach signal that (112B) transmission is exaggerated on guide rail (102).
Produce the feedback (612) of the voltage that expression sends along guide rail (102) near track circuit (602), and the feedback (678) of the electric current that sent of expression.Differential amplifier can be used to provide and send voltage feedback (612) and send current feedback (678).For example, differential input amplifier (607) is connected to lead (112A) and (112B), and mouth provides the feedback voltage (612) of the voltage of the approach signal that expression sends.In series insert resistor (609) with output lead (112B), and differential input amplifier (611) has the input end of the respective end that is connected to resistor (609), so that provide expression to be applied to the feedback current signal (678) of value of the constant current of track.The voltage feedback that is received (614) expression by receptor by the lead (116A) and the approach signal voltage that is sent of (116B) picking up.In one embodiment, receptor (615) is to have another the differential input amplifier that is connected to point of connection (116A) and input end (116B), and is the voltage of the approach signal that received of expression from the output signal of amplifier.Feedback (612), (678) and (614) are provided to the data acquisition system (617) that comprises track circuit feedback (616), antialiasing filter (618) and multiplexer (620).As known to persons of ordinary skill in the art, multiplexedly comprise that the form with single complex signal (being multiplex signal) sends a plurality of signals or flow of information simultaneously.In this case, antialiasing filter (618) receives and sends voltage feedback (612), sends current feedback (678) and receives voltage feedback (614), to eliminate the noise in the feedback signal that is for example received.Multiplexer (620) is coupled to antialiasing filter, and multiplexed filtered first sends voltage feedback (612), filtered first sends current feedback (678) and filtered first and receives voltage feedback (614), to produce multiplexed analog signal (622).Provide multiplexed analog signal (662) to analog-digital converter (662), in this analog-digital converter,, and convert thereof into corresponding to sending voltage feedback (612) and sending current feedback (678) and first digital signal of reception voltage feedback (614) to analog signal sampling and digitalisation.In DSP (604), first digital signal is carried out digital band pass filtering, and handle filtered data, to determine signal level and phase place.Particularly, first digital signal is handled, with frequency and the amplitude of determining to send voltage feedback (612) and send current feedback (678) and receive voltage feedback (614).Secondary signal handled also comprise second digital signal carried out digital filter, with the frequency of determining to receive voltage feedback (614) whether in first free transmission range.If determine to receive voltage feedback (614) in first free transmission range, then DSP (604) uses determined signal level (amplitude just) and phase data to calculate total impedances, and total impedances has been determined existence and the motion near train in the track circuit (128) again.In alternative embodiment, DSP (604) provides the data that comprise signal level and signal phase for the different treater (not shown) that calculates total impedances, and total impedances has been determined existence and the motion near train in the track circuit (128) again.
Similarly, second digital signal processor (DSP B) (654) produces the sine wave signal output (656) to second sine wave generator (658), to produce island sine wave signal (660).Provide island sine wave signal (560) to island transmitter (664), island transmitter (664) amplifies island sine wave signal (660) based on the island gain control signal (663) that is provided by the 2nd DSP (654).By non-conductive transmitter leads (113A) with (113B) the island signal that amplifies is sent on the guide rail (102).Certainly in different embodiment, island track circuit (110) can adopt identical transmission lead group.
The feedback (670) of the voltage that the feedback (666) of the voltage that island track circuit (650) generation expression is sent and generation expression are received.In this case, differential input amplifier (665) can be connected to lead (113A) and (113B), and mouth provides the feedback voltage (666) of the voltage of the approach signal that expression sends.Receive voltage feedback (670) expression by receptor through lead (116A) and the island signal voltage that is sent that (116B) picks up.The data acquisition system (671) that comprises track circuit feedback (668), antialiasing filter (672) and multiplexer (674) is provided transmission voltage feedback (666) and receives voltage feedback (670), to produce multiplexed analog signal (675).Provide the second multiplexed analog signal (675) to analog-digital converter (676), in this analog-digital converter (676), signal is carried out digitalisation, and convert thereof into second digital signal.In DSP (654), second digital signal is carried out digital band pass filtering, and handle filtered data, to be used for determining of signal level.Particularly, second digital signal is handled, with frequency and the amplitude of determining to send voltage feedback (666) and receiving voltage feedback (670).Secondary signal handled also comprise second digital signal carried out digital filter, with the frequency of the secondary signal determining to be received whether in second passband frequency range of contiguous first passband frequency range.If the frequency of definite secondary signal that is received is in second free transmission range, then DSP (654) uses determined signal level (amplitude just) to determine the existence of train in the island (118).
Other embodiment that it should be understood that native system can adopt the individual digit signal processor, maybe can adopt any amount of digital signal processor, and aspect still according to the invention.In such embodiment, with aforesaid couple of DSP of redundant mode operation, wherein each treater detects the island track signal and individually near track signal.In this embodiment, two DSP provide their independent data to external system, and this external system is two-fold and redundant data relatively, and carry out necessary train alarm and determine.
Another embodiment of native system is the signal of sampling and recovering from track with the integral multiple of the frequency that sends signal.With reference to Fig. 6, DSP A (604) and sine wave generator (606) be used to produce frequency be Af near sine wave signal (608).In order to help digital signal processing, and finally increase the accuracy rate of received signal, DSP A (604) provide with near the sampling clock (not shown) be the programmable clock of form to the analog-digital converter ADCA (662) that can be programmed to N times of Af, wherein N is an integral value (just 1,2,3 ... Deng).Identical method is used to the island circuit, and wherein DSP B (654) and sine wave generator (658) generation frequency is the island sine wave signal (660) of Ai.DSP B (654) provides programmable clock as island sampling clock (not shown) to the ADC B (676) that is programmed to Q times of Ai, and wherein Q is an integral value (just 1,2,3 ... Deng).Need select N and Q based on DSP FIR and/or iir filter design.This allows the optimization filter coefficient, with the transmission signal that recovers to be discussed, and only can realize resulting data acquisition and filter noise from signal by changing dsp software.
Another embodiment of native system is that antialiasing filter also is by the dsp software programmable.Referring again to Fig. 6, DSP A (602) provides programmable clock (682) to give the antialiasing filter A (602) that is programmed to M times of Af now.Similarly, DSP B (654) provides programmable clock to the antialiasing filter B (672) that is programmed to P times of Ai.In one embodiment, utilize the switched capacitor filters device to realize the antialiasing filter circuit.Need select M and P based on device needs that are used for signal outside the rejection band and antialiasing filter (AAF).This permission realizes desired bandpass filtering by only changing dsp software.
Another embodiment of native system is by making data acquisition sampling clock and antialiasing filter clock able to programme, only needs a kind of hardware configuration to realize and supports to be used for the whole frequency limit of level crossing system.This system that has to make and store that has reduced to reduce with quantity is the cost of the maker of form, and has reduced the cost of the user aspect the stand-by system of having to buy and keep of lesser amt.
Though in conjunction with railroad grade crossing, more specifically in conjunction with the improvement system and the technology that the detection near the train of this crossing have been illustrated the application that is used to produce and detect the signal that sends along railroad rails, system of the present invention and technology also can be used for other railway roadside and use.For example, train detection is carried out in the operation that can be used to be combined in the interlocking equipment of the switch between the track of described system and technology.
In addition, described system and technology can be used for track circuit applications, wherein locate transmitter and receptor along guide rail in position at interval, with existing of train in the interval between detection transmitter and the receptor.They also can be used for the operator's compartment signaling, wherein along guide rail location transmitter, and on locomotive location receivers, to be used for sending information to locomotive, such as signal aspect information from the roadside.
Referring now to Fig. 7, exemplary flow chart has illustrated according to one embodiment of the present of invention and has been used for detecting the existence of surveyed area rolling stock of railroad track and/or the method for position.In (702), send first signal along the guide rail of railroad track with predetermined amplitude and predetermined work frequency.In (704), for example receive first signal that is sent out along guide rail by receptor.In (706), produce first analog signal of expression first signal that is sent and first signal that is received.In (708), first analog signal conversion is become corresponding to a plurality of first digital signals of first signal that is sent with first signal that is received.In (710), first digital signal is handled, to determine the frequency and the amplitude of first signal that is sent and first signal that is received.First digital signal handled comprise first digital signal carried out digital filter, with the frequency of first signal determining to be sent whether in first passband frequency range.Handle also comprise determine as work as first signal that received in first passband frequency range time near surveyed area in the existence of train and/or impedance indication, track of position.In (712), send secondary signal along the guide rail of railroad track with predetermined amplitude and different predetermined work frequency.In (714), for example receive the secondary signal that is sent out along guide rail by receptor.In (716), produce second analog signal of expression secondary signal that is sent and the secondary signal that is received.In (718), second analog signal conversion is become corresponding to a plurality of second digital signals of the secondary signal that is sent with the secondary signal that is received.In (720), second digital signal is handled, to determine the frequency and the amplitude of secondary signal that is sent and the secondary signal that is received.Second digital signal handled comprise second digital signal carried out digital filter, with the frequency of the secondary signal determining to be sent whether in second passband frequency range of contiguous first passband frequency range.Handle the amplitude also comprise definite secondary signal that receives and be on the threshold values or under, the secondary signal that receives as working as is the existence of train and/or the indication of position in the surveyed area of island in second passband frequency range time.In one embodiment, threshold values is corresponding to the predetermined percentage that sends voltage.
For example, for the transmission voltage of 100 millivolts (mV), threshold values can be 80% (80mV just) that sends voltage.The decline of 20mV is corresponding to the watt loss of the expection that occurs in the process of transmitting on guide rail at signal.If the secondary signal that is received has the amplitude that is lower than 80mV, can suppose that then train is present in the surveyed area of island.Alternately, if the secondary signal that is received has the amplitude greater than 80mV, just suppose that train is not in the surveyed area of island.Top voltage amplitude and threshold values only are to be used for the illustrative purpose, and can consider, can use various voltage amplitudes and/or threshold values when enforcement is of the present invention.
When introducing the parts of the present invention or embodiment, article " ", " one ", " being somebody's turn to do " and " described " are intended to expression and are had one or more parts.Term " comprises ", " comprising " and " having " mean and included, and mean the optional feature that can have except the parts of listing.
Owing to can in superincumbent without departing from the scope of the invention structure, change, therefore comprise in the superincumbent explanation or total material illustrated in the accompanying drawings should be understood that illustrative, and do not have the meaning of restriction.
Claims (9)
1, a kind of existence of the surveyed area rolling stock that is used for detecting railroad track (102) and the train detection systems of position, the impedance that described railroad track has pair of guide rails (106) and discerned in described surveyed area, and the impedance of the described track of the existence of rolling stock and/or position change (102) in the wherein said surveyed area, described train detection systems comprises:
First transmitter (610), the guide rail (106) that it is connected to described railroad track (102) is used for sending first signal with first predetermined amplitude and first predetermined work frequency along described guide rail (106);
Second transmitter (665), it is connected to the guide rail (106) of described railroad track (102), be used for sending the secondary signal with second predetermined amplitude and second predetermined work frequency along described guide rail (106), the described second predetermined work frequency is different from the described first predetermined work frequency;
Receptor (615), it is connected to described guide rail, is used to receive described first and second signals;
First data acquisition unit (617), it is coupled to described first transmitter (610) and described receptor (615), and response first signal that is sent and first signal that is received, to produce the first multiplexed analog signal (622) of expression first signal that is sent and first signal that is received;
Second data acquisition unit (671), it is coupled to second transmitter (664) and described receptor (615), and response secondary signal that is sent and the secondary signal that is received, to produce the second multiplexed analog signal (675) of expression secondary signal that is sent and the secondary signal that is received;
First conv (662) is used for the described first multiplexed analog signal (622) is converted to corresponding to a plurality of first digital signals of first signal that is sent with first signal that is received;
Second conv (676) is used for the described second multiplexed analog signal (675) is converted to corresponding to a plurality of second digital signals of the secondary signal that is sent with the secondary signal that is received;
First digital signal processor (604), it responds described first digital signal and described first digital signal is handled, whether in first passband frequency range, wherein said first passband frequency range is the function of the frequency of first signal that sent with the frequency of first signal determining to be received;
Second digital signal processor (654), it responds described second digital signal and described second digital signal is handled, whether in second passband frequency range of contiguous described first passband frequency range, wherein said second passband frequency range is the function of the frequency of the secondary signal that sent with the frequency of the secondary signal determining to be received; And
Treater, it responds described first digital signal and described first digital signal is handled, to determine the frequency and the amplitude of first signal that is sent and first signal that is received, thereby determine as work as first signal that received in described first passband frequency range time near surveyed area in the indication of the existence of train and/or position, the impedance of described track (102), and wherein said treater responds described second digital signal and described second digital signal is handled, and whether is lower than the indication that exists of train in the surveyed area of island in described second passband frequency range time of secondary signal that threshold values received as working as with the amplitude of determining secondary signal.
2, according to the described train detection systems of claim 1, wherein said first data acquisition unit (617) comprising:
First reactive circuit (616), be used to detect by described first transmitter be applied to that first of described guide rail sends voltage signal, first current signal that sends along described guide rail (106) by described first transmitter (610) and first receive voltage signal by what described receptor (615) received;
First filter (618), it is coupled to described reactive circuit (661), is used for sending voltage signal, detected first current signal that sends and the detected first reception voltage signal to detected first and carries out filtering; And
First multiplexer (620), it is coupled to described first filter (618), be used for multiplexed filtered first and send voltage signal, filtered first current signal and the filtered first reception voltage signal, producing the first multiplexed analog signal (622), and wherein said treater calculate as first send voltage signal, first receive voltage signal and first send the difference between the current signal function, near the impedance of surveyed area middle orbit.
3, according to the described train detection systems of claim 1, wherein said second data acquisition unit (671) comprising:
Second reactive circuit (668) is used to detect the second reception voltage signal that is applied to the second transmission voltage signal of described guide rail and passes through described receptor reception by described second transmitter;
Second filter (672), it is coupled to described reactive circuit, is used for that the detected second transmission voltage signal and detected second is received voltage signal and carries out filtering; And
Second multiplexer (674), it is coupled to described second filter (672), is used for multiplexed filtered second and sends voltage signal and the filtered second reception voltage signal, to produce the second multiplexed analog signal (675).
4, according to the described train detection systems of claim 1, the bandwidth of wherein said first passband frequency range is corresponding to 3 percent of the positive and negative of the described first predetermined work frequency, and the bandwidth of wherein said second passband frequency range is corresponding to 3 percent of the positive and negative of the described second predetermined work frequency.
5, according to the described train detection systems of claim 4, wherein between described first passband frequency range and second passband frequency range, separation band is arranged, this separation band defines a frequency limit, and described train detection systems also comprises first and second digital filters, and they are configured to make described separation band to minimize and increase the quantity that is used in the frequency of operation in the single checking system simultaneously.
6, a kind of existence of the surveyed area rolling stock that is used for detecting railroad track and/or the method for position, the impedance that described railroad track has pair of guide rails and discerned in described surveyed area, and the impedance of the existence of rolling stock and/or the described track of position change in the wherein said surveyed area, described method comprises:
Send first signal with predetermined amplitude and predetermined work frequency along described guide rail;
First signal that reception is sent out along described guide rail;
Produce first analog signal of expression first signal that is sent and first signal that is received;
Described first analog signal conversion is become corresponding to a plurality of first digital signals of first signal that is sent with first signal that is received;
Described first digital signal is handled, and with the frequency and the amplitude of definite first signal that is sent and first signal that is received, thereby the impedance of definite track conduct is near the existence of train in the surveyed area and/or the indication of position;
Send secondary signal with predetermined amplitude and different predetermined work frequency along described guide rail;
The secondary signal that reception is sent out along described guide rail;
Produce second analog signal of expression secondary signal that is sent and the secondary signal that is received;
Described second analog signal conversion is become corresponding to a plurality of second digital signals of the secondary signal that is sent with the secondary signal that is received; And
Described second digital signal is handled, whether be lower than the indication that exist of threshold values as train in the surveyed area of island with the amplitude of the secondary signal determining to be received.
7, in accordance with the method for claim 6, wherein to described first digital signal handle comprise determine as the function of the rate of change of described impedance, the speed of train in the surveyed area.
8, in accordance with the method for claim 6, wherein described first digital signal is handled and comprised described first digital signal is carried out digital filter, with the frequency of first signal determining to be received whether in first passband frequency range, described first passband frequency range is the function of the frequency of first signal that sent, and wherein handles and further comprise described first digital signal is handled impedance when determining that frequency when determined first signal that is received is in described first passband frequency range.
9, in accordance with the method for claim 6, wherein described second digital signal is handled and comprised described second digital signal is carried out digital filter, with the frequency of first signal determining to be received whether in second passband frequency range of contiguous described first passband frequency range, wherein said second passband frequency range is the function of the frequency of the secondary signal that sent, and wherein described second digital signal is handled and comprised further also whether the amplitude that described second digital signal is handled the secondary signal that is received when determining that frequency when the determined secondary signal that is received is in described second passband frequency range is lower than threshold values.
Applications Claiming Priority (3)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US44719503P | 2003-02-13 | 2003-02-13 | |
| US60/447,195 | 2003-02-13 | ||
| US10/743,591 | 2003-12-22 |
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| Publication Number | Publication Date |
|---|---|
| CN1750958A CN1750958A (en) | 2006-03-22 |
| CN100569569C true CN100569569C (en) | 2009-12-16 |
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| CNB2004800041203A Expired - Lifetime CN100569569C (en) | 2003-02-13 | 2004-02-13 | Be used for detecting automatically digital train system near the train of crossing |
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| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE102009010907A1 (en) * | 2009-03-02 | 2010-09-16 | Siemens Aktiengesellschaft | Device for detecting the occupancy and free status of a track section and method for operating such a device |
| CN105799735B (en) * | 2016-05-19 | 2017-09-15 | 北京全路通信信号研究设计院集团有限公司 | Track circuit transmitter and fault guiding safety implementation method |
| CN115535027B (en) * | 2022-12-01 | 2023-04-14 | 成都盛锴科技有限公司 | Wheel quality judgment method and system for rail vehicle |
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