EP2924662B1 - Onboard unit and method for functional monitoring in a road toll system - Google Patents

Description

The present invention relates to an on-board unit for a road toll system, comprising a satellite navigation receiver for the continuous generation of position fixes and associated quality measurements from raw satellite data, a radio transceiver and a processor connected to these components, which is adapted to generate toll data from the position fixes and via the Radio transceiver to send. The invention further relates to a method for monitoring the function in a road toll system using such an on-board unit.

Onboard units (OBUs) based on satellite navigation systems (GNSS) may e.g. Be "Thick Client" OBUs, which match the position fixes generated with a stored in the onboard unit digital road map, thereby determine toll routes, calculate related tolls and send as toll data on the radio transceiver, but also "thin client" OBUs, which directly send the position fixes as toll data to a central office, which calculates the tolls. The functionality and performance of such GNSS OBUs depends largely on the quality of their satellite reception and the resulting position fixes.

In the EP 1 696 207 A1 For example, a method is described for classifying position fixes, where due to their quality, invalid position fixes are discarded or marked, and position fixes with usable raw satellite data use only that raw data or metadata derived therefrom, but not the position fixes themselves.

While billing tolls is usually in the hands of the road owner or an authority, the so-called "toll chargers", the generation of toll data or the calculation of tolls is usually as a service by a "service Provider ", the service provider has a certain capacity, for example, to guarantee a certain Vermustungsgrad on a toll road.
To measure the functionality and performance of a road toll system fleets of test vehicles are currently used, for example, the predetermined toll routes random samples Departure to then compare the tolls incurred in the headquarters of the Toll Chargers with the random checks. To reduce the personnel and organizational effort beats the EP 2 665 044 Alternatively, the Toll Charger will request individual toll onboard units to randomly collect positional data and send as reference data directly to the Toll Charger toll center where it compares the reference data with the tolls generated by the service provider during operation to improve performance of the road toll system.

The invention has for its object to provide devices and methods for functional testing in a road toll system, which allow as a result an improvement in the performance of the road toll system and thus an increase in Vermustungsgrades.

This object is achieved according to a first aspect of the invention with an onboard unit of the aforementioned type, which is characterized by
a failure detector connected to the satellite navigation receiver adapted to respond to a lack of position fixes over a predetermined minimum time period or a drop in quality measurements below a predetermined minimum quality measure; and
a logger connected to the satellite navigation receiver and controlled by the failure detector, which is adapted to generate an error record with at least the last position fix before the response when the failure detector responds;
wherein the processor is adapted to receive the error record from the logger and send it via the radio transceiver.

• Detektieren eines Ausbleibens von Positionsfixen über eine vorgegebene Mindestzeitspanne oder eines Abfallens von Qualitätsmesswerten unter ein vorgegebenes Mindestqualitätsmaß in der Onboard-Unit,
• im Falle der Detektion, Protokollieren eines Fehlerdatensatzes mit zumindest dem letzten Positionsfix vor der Detektion in der Onboard-Unit,
• Senden des Fehlerdatensatzes von der Onboard-Unit an die Zentrale, und
• Auswerten des Fehlerdatensatzes in der Zentrale.

According to a second aspect, the invention provides a method for functional measurement in a road toll system with a control center and at least one onboard vehicle-based unit, which continuously generates position fixes and associated quality measurements from raw satellite data and sends toll data based thereon to the center, comprising:

• Detecting a lack of position fixes over a predetermined minimum time period or a drop of quality measurements below a predetermined minimum quality measure in the onboard unit,
• in the case of detection, logging an error data record with at least the last position fix before the detection in the on-board unit,
• Sending the error record from the onboard unit to the control panel, and
• Evaluation of the error data record in the control center.

According to the invention, this makes it possible for the first time to make the quality of the GNSS position determination and coverage in the road toll system accessible to a central evaluation and thereby to determine critical GNSS fault locations in the road network at an early stage and to allocate them geographically on the basis of the last position fix. Instead of a mere random performance check, position detection errors of GNSS OBUs can be evaluated continuously or, if the OBUs are spread, continuously and at short intervals in the control center. As a result, different GNSS-related errors in the road toll system, e.g. Spurious signals, shadowing of the satellite signals, etc., and their causes, e.g. local or even mobile interference sources ("jammers") or geographical conditions such as mountains or tunnels closed. Thus, for the first time, measures for fault elimination, for example, at the error locations respectively bounded by the last position fixes, can be targeted. the setting up of stationary position transmitters, support beacons, satellite signal repeaters or the like, or the identification and switching off of interference signal sources, etc., are initiated.

It is particularly favorable if the error data record generated by the onboard unit has a time stamp of the last named Contains position fixes. Thus, from a plurality of error data sets of different onboard units or one and the same onboard unit at different times of day or seasons on time-dependent errors and causes of errors, such as time-varying or periodic interference, unfavorable satellite constellations or shadowing of the satellite signals in response to weather events or by vegetation during the growing season, etc., be inferred. Further, the movement of a mobile jamming signal source can be accurately tracked to identify, for example, "jamming" that deliberately sends jamming signals to hinder proper building, using traffic cameras and / or emergency vehicles.

In order to distinguish the geographical areas of the detected error even better, it is particularly advantageous if the error data set also contains the first position fix generated after the completion of the response or detection. For this reason, the error data record preferably also contains a time stamp of the named first position fix.

In a favorable embodiment of the invention, the error data set also contains at least one quality measurement value generated during the response of the failure detector or detection of the failure. This makes it possible to draw conclusions about the causes of faults even more precisely. Thus, if the quality measurement contains, for example, the number of satellites used to generate the associated position fix or a DOP value (Dilution of Precision) of the associated position measurement value, an unfavorable satellite constellation could be detected - accidentally or locally frequently. If, for example, the quality measured value contains the respective signal level of the satellite used to generate the associated position measured value and / or a signal / noise ratio of the satellite signals, then interference signals or signal attenuation can also be caused, for example as a result of local, possibly even mobile jammers or from weather events or shadowing by mountains or forest.

It will be appreciated that an error record may include not only one but also a series of quality measurements generated during the response of the failure detector, resulting in an evaluation of the history of the quality measurements and thus more accurate conclusions, e.g. allowed over possibly different error causes.

The error data record preferably also contains satellite raw data received during the response of the failure detector or detecting the failure and / or sensor measured values generated in a sensor element, thereby providing further bases for a later determination of possible causes of the error.

It is particularly favorable if the failure detector contains a watchdog which is newly abuttable by each position fix generated. This represents a particularly simple, reliable component for the failure detector.

In a further preferred embodiment of the method according to the invention, at least one second error data record generated and sent by a second on-board unit in the manner mentioned is received in the center, and the error data records of the at least two on-board units are validated against one another during the evaluation. Thereby temporal changes of possible causes of faults can be considered more easily and individual faults or faults of individual onboard units, e.g. due to an improper arrangement in the vehicle, be compensated. At the same time, the number of available onboard units in the evaluation of the error data sets increases their informative value with regard to possible causes of error.

It is particularly advantageous if geographic interference and shading ranges of the satellite reception are determined during evaluation by matching the error data records with a digital map. This creates a "map of GNSS errors" that are matched to geographic conditions such as high mountains, narrow valleys, tunnels, etc. can. In this way, inherent technical causes of error are more easily distinguishable and remedial actions can be initiated.

• Fig. 1 ein Straßenmautsystem mit fahrzeuggestützten Onboard-Units gemäß der Erfindung in einer schematischen Draufsicht;
• Fig. 2 ein Blockschaltbild einer der Onboard-Units von Fig. 1; und
• Fig. 3 beispielhafte Daten- und Signaldiagramme, die in der Onboard-Unit von Fig. 2 und während der Ausführung des Verfahrens der Erfindung auftreten.

The invention will be explained in more detail with reference to an embodiment shown in the accompanying drawings. In the drawings shows:

• Fig. 1 a road toll system with vehicle-mounted on-board units according to the invention in a schematic plan view;
• Fig. 2 a block diagram of one of the onboard units of Fig. 1 ; and
• Fig. 3 exemplary data and signal diagrams contained in the onboard unit of Fig. 2 and occur during the performance of the method of the invention.

Fig. 1 shows a road toll system 1 based on onboard units (OBUs) 2, which are carried by vehicles 3 in order to toll their usage in a network of roads 4. The location use, for example, the driving of a particular segment of a road 4, crossing a border, the residence in a particular geographical area or the like. be and in any way, for example, per road segment, distance traveled, in a region of time spent (eg parking time), etc. billed.

According to Fig. 2 For this purpose, each on-board unit 2 has a satellite navigation receiver 5, which consists of satellite signals 6 from navigation satellites 7 (FIG. Fig. 1 ) of a global navigation satellite system (GNSS) continuously determines the position of the on-board unit 2 and as position fixes p ₁ , p ₂ ,..., generally p _i , with associated quality measurement values q ₁ , q ₂ , ... , generally q _i , outputs.

Each quality measurement q _{i of} a position fix p _i can contain various quality parameters, for example the number, signal level and / or signal / noise ratio of the signals 6 of the navigation satellites 7 used for determining the respective position fix p _i , eg also in evaluated form The form of dilution of precision (DOP) values provided by commercially available satellite navigation receivers 5 for each position fix p _i .

In addition to the position fixes p _i and their quality measurements q _i , the satellite navigation receiver 5 can also output the underlying "raw" satellite data, eg sections of the satellite signals 6, or processing data formed during the generation of the position fixes p _i , hereinafter "raw satellite data" r _i called. The output of the position fixes p _i , quality measurements q _i or raw satellite data r _i can take place on mutually separate outputs of the satellite navigation receiver 5, on a common output in multiplexing or on a common bus in separate data packets.

The on-board unit 2 is further provided with a radio transceiver 8, e.g. according to a 2G, 3G, 4G or 5G mobile radio standard such as GSM, UMTS or LTE, the ITS-G5 or WAVE standard for short-range radio communication, one of the IEEE 802.11 standards for WLAN communication or the like, and a processor 9 connected to the satellite navigation receiver 5 and the radio transceiver 8.

Optional may also be one or more sensor elements 10, for example, velocity or acceleration sensors, are provided, which in the onboard unit 2 itself, or - connected to the on-board unit 2 - may be arranged in the vehicle 3, and sensor measurements m _i, for example, speed , Acceleration or approximate local measured values generate. Such a sensor element 10 can also be formed by the radio transceiver 8, in which case the sensor measured values m _{i are} metadata of the radio transceiver 8, eg radio cell or received field strength data of a radio connection 11 to a radio station 12, here a base station of a mobile radio network in which the radio transceiver 8 is located.

The processor 9 generates toll data M from the sequence {p _i } of position fixes p _{i in} order to use the radio transceiver 8 via the radio link 11 and the radio station 12 to a central office 13 of the road toll system 1 to send.

The toll data M may be, for example, tolls, which are generated by a map matching of the position fix sequence {p _i } with a digital toll road 4 or places stored in the on-board unit 2. Alternatively, the toll data M could also be the position fixes p _i itself, which are individually or - if desired filtered according to quality - combined into a bundle at arbitrary or predetermined times, after predetermined distances or simply with the availability of a radio link 11 via the radio transceiver 8 sent. In the latter case, card matching and billing can be done for example in the center 13.

According to Fig. 1 the vehicles 3 pass through a geographical area 14 on their respective routes on the roads 4 in which the satellite signals 6 received by the satellite navigation receivers 5 are disturbed, so that the quality measurements qi fall off and / or the respective satellite navigation receivers 5 do not generate position fixes p _i ,

Fig. 3 shows in this example of waveforms of the respective signals or data of an on-board unit 2. According to this example generates the satellite navigation receiver 5 at times t _1, t _2, ..., generally _i t, from the raw satellite data r _i (not shown) each having a Position fix p _i ( Fig. 3a ) and an associated quality measurement q _i ( Fig. 3c ). If the vehicle 3 passes through said geographical area 14, the satellite navigation receiver 5 does not generate any position fixes p _i over a period of time e, but in general continues to produce quality measured values q _i .

To errors of the position determination of the on-board unit 2 and thus the Vermautungsfunktion the road toll system 1, for example due to signal interference and / or shadowing of the satellite signals The following components and procedures are used to detect and measure.

The on-board unit 2 has a connected to the satellite navigation receiver 5 failure detector 15 which responds and an output signal s ( Fig. 3e ) generates, for example, a logical "high" signal or a logical "1" if it either (a) the absence of position fixes p _i over a predetermined minimum period of time δ and / or (b) a drop of quality measured values q _i below predetermined minimum quality measure Q _min detected.

In order to detect the event (a), the failure detector 15 may have a watchdog 16, eg in the form of a deadman or retriggerable monoflop circuit, which is triggered by each new position fix p _i at its input again for the minimum period of time δ and thus at its (here: inverted) output a detection signal d ( Fig. 3b ) outputs, if within the specified minimum period δ no new position fix p _i attains.

Alternatively or in addition to the watchdog 16, the failure detector 15 for detecting the event (b) may have a comparator 17 which compares the incoming quality measurements q _i with a minimum quality measure Q _min , and an output c when the quality measures q _i fall below the minimum quality measure Q _min ( Fig. 3d ). Depending on the complexity of the quality measurements qi, to simplify this comparison, it may be desirable for the comparator 17 to first combine a quality metric q _i containing several parameters (dimensions) into a single global quality metric Q _i ; alternatively, the minimum quality measure Q _min could include separate single thresholds for a plurality of quality parameters included in a quality metric q _i .

The output signals c of the watchdog 16 and d of the comparator 17 can be linked, for example, by a simple OR circuit 18 to the output signal s of the failure detector 15. Instead of the OR circuit 18 may also be a complex Auswertelogik, which, for example, the timing of the signals c and d also taken into account, are provided. If the failure detector 15 contains only one of the components watchdog 16 or comparator 17, the circuit 18 is omitted and the output signal s coincides with the signal c or d.

The output signal s generated by the failure detector 15 activates a logger 19 which, in the case of said events (a) and / or (b), generates an error record F and makes it available to the processor 9 for transmission via the radio transceiver 8 to the center 13. As in Fig. 2 symbolically shown, the logger 19 is, for example, a recording unit 20 with a buffer memory 21 connected to one or more outputs of the satellite navigation receiver 5.

• einen Zeitstempel t_m des genannten letzten Positionsfixes p_m;
• den ersten unmittelbar nach Beendigung des Ansprechens des Ausfallsdetektors 15 erzeugten Positionsfix p_n, wenn gewünscht auch mit zugehörigem Zeitstempel t_n;
• die zum genannten letzten und/oder ersten Pösitionsmesswert p_m, p_n erzeugten Qualitätsmesswerte q_m und/oder q_n;
• einen oder mehrere der während des Ansprechens des Ausfallsdetektors 15, d.h. solange der Protokollierer 19 angesteuert (s = "1") ist, erzeugten Qualitätsmesswerte q_i, wenn gewünscht auch mit zugehörigen Zeitstempeln t_i;
• die zum genannten letzten und/oder ersten Positionsmesswert p_m, p_n und/oder während des Ansprechens des Ausfallsdetektors 15 (s = "1") empfangenen - bzw. gebildeten - Satellitenrohdaten r_i; und/oder
• die etwa zeitgleich mit dem genannten letzten und/oder ersten Positionsmesswert p_m, p_n und/oder während des Ansprechens des Ausfallsdetektors 15 (s = "1") erzeugten Sensormesswerte m_i .

As an error record F, the logger 19 in the simplest case records the last position fix p _m that the satellite navigation receiver 5 generated just before the response of the failure detector 15, see FIG Fig. 3a , In addition, the logger 19 can add further data to the error data record F as required so that it can also contain, individually or in any combination:

• a time stamp t _m of said last position fix p _m ;
• the first position fix p _n generated immediately after completion of the response of the failure detector 15, if desired also with the associated time stamp t _n ;
• the last-mentioned to and / or first Pösitionsmesswert _m p quality metrics generated p _n q _m and / or q _n;
• one or more of the generated during the response of the failure detector 15, ie as long as the logger 19 is driven (s = "1"), generated quality measurements q _i , if desired, with associated timestamps t _i ;
• the said last and / or first position measurement value p _m , p _n and / or during the response of the failure detector 15 (s = "1") received - or formed - satellite raw data r _i ; and or
• the sensor measured values m _i generated approximately at the same time as the last and / or first position measured value p _m , p _n and / or during the response of the failure detector 15 (s = "1").

Optionally, the logger 19 may pre-process the error record F, for example, by exiting redundant or irrelevant data, supplementing with environment data from the environment of the on-board unit 2 or internal status data of the on-board unit 2, data summary, etc. depending on the situation.

In the center 13, the received error records F are evaluated. This evaluation can on the one hand be done individually, i. the error data sets F of an on-board unit 2 are considered on their own; on the other hand, a plurality of error data sets F of different on-board units 2 can also be received, jointly evaluated and, for example, evaluated. be validated against each other.

In the evaluation, the error data sets F are determined as a function of the position fixes p _m , p _n , {p _i } and, if detected, their time stamps t _m , t _n , {t _i }, quality measurements q _m , q _n , { q _i }, raw satellite data {r _i } and / or sensor readings {m _i } are considered and analyzed for possible sources of error in order to prepare measures for their elimination. Optionally, when evaluating the error data sets F with a digital map, geographic interference and shading regions 14 of the satellite reception as well as their time dependency may be determined. Thus, permanent shadowing, eg through tunnels, can be recognized and temporary shading, eg in narrow valleys, where only a sufficient number of satellite signals 6 can be received at a given intensity, or weather-related signal attenuation or season-dependent shadowing in dense vegetation of fixed or moving sources of interference ("whining"), etc., etc. As a result, targeted measures for fault elimination can be initiated. to increase the Vermustungsgrad the road toll system 1, for example, stationary position transmitter or satellite signal repeater built or sources of interference eliminated or switched off or deliberate transmission of jamming signals are tracked and punished.

The invention is not limited to the illustrated embodiments, but includes all variants and modifications that fall within the scope of the appended claims. Thus, the onboard unit 2 as a whole or individual ones of its components, such as the failure detector 15, the logger 19 or parts thereof both as hardware components and as software objects, e.g. in the processor 9.

Claims (15)

1. Onboard unit for a road toll system (1), comprising
   a satellite navigation receiver (5) for continuously generating position fixes (p_i) and associated quality measurement values (q_i) from satellite raw data (r_i),
   a radio transceiver (8), and
   a processor (9) connected to these components (5, 8), which is configured to generate toll data (M) from the position fixes (p_i) and to send the toll data via the radio transceiver (8),
   characterized by
   an outage detector (15) connected to the satellite navigation receiver (5), which outage detector (15) is configured to respond to an absence of position fixes (p_i) over a given minimum time span (δ) or to a drop in quality measurement values (q_i) under a given minimum quality measurement (Q_min), and
   a recorder (19) connected to the satellite navigation receiver (5) and controlled by the outage detector (15), which recorder (19) is configured to generate, when the outage detector (15) responds, an error dataset (F) with at least the last position fix (p_m) before the response,
   wherein the processor (9) is configured to receive the error dataset (F) from the recorder (19) and to send it via the radio transceiver (8).
2. Onboard unit according to claim 1, characterized in that the error dataset (F) also contains a time stamp (t_m) of said last position fix (p_m).
3. Onboard unit according to claim 1 or 2, characterized in that the error dataset (F) also contains the first position fix (p_n) generated after the response has finished.
4. Onboard unit according to claim 3, characterized in that the error dataset (F) also contains a time stamp (t_n) of said first position fix (p_n).
5. Onboard unit according to any one of the claims 1 to 4, characterized in that the error dataset (F) also contains at least one quality measurement value (q_i) generated during responding.
6. Onboard unit according to any one of the claims 1 to 5, characterized in that the error dataset (F) also contains satellite raw data (r_i) received during responding and/or sensor measurement values (m_i) generated in a sensor element (10).
7. Onboard unit according to any one of the claims 1 to 6, characterized in that the outage detector (15) contains a watchdog (16), which can be triggered anew by each generated position fix (p_i).
8. Method for function surveillance in a road toll system (1) with a central station (13) and at least one vehicle mounted onboard unit (2), which continuously generates position fixes (p_i) and associated quality measurement values (q_i) from satellite raw data (r_i) and sends toll data (M) based thereupon to the central station (13), comprising:

   detecting an absence of position fixes (p_i) over a given minimum time span (δ) or a drop in quality measurement values (q_i) under a given minimum quality measurement (Q_min) in the onboard unit (2), and

   in case of a detection, recording an error dataset (F) with at least the last position fix (p_m) before the detection in the onboard unit (2),

   sending the error dataset (F) from the onboard unit (2) to the central station (13), and

   evaluating the error dataset (F) in the central station (13).
9. Method according to claim 8, characterized in that the error dataset (F) also contains a time stamp (t_m) of said last position fix (p_m).
10. Method according to claim 8 or 9, characterized in that the error dataset (F) also contains the first position fix (p_n) generated after the detection has finished.
11. Onboard unit according to claim 10, characterized in that the error dataset (F) also contains a time stamp (t_n) of said first position fix (p_n).
12. Onboard unit according to any one of the claims 8 to 11, characterized in that the error dataset (F) also contains at least one quality measurement value (q_i) generated during detecting.
13. Onboard unit according to any one of the claims 8 to 12, characterized in that the error dataset (F) also contains satellite raw data (r_i) received during detecting and/or sensor measurement values (m_i) generated in a sensor element (10).
14. Onboard unit according to any one of the claims 8 to 13, characterized in that in the central station (13) at least a second error dataset (F), generated and sent by a second onboard unit (2) in said manner, is received and in that the error datasets (F) of the at least two onboard units (2) are validated against each other during evaluating.
15. Onboard unit according to any one of the claims 8 to 14, characterized in that, during evaluating, geographical interference and shadowing regions (14) of the satellite reception are determined by comparing the error datasets (F) with a digital map.

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