CN109661859B - Method for controlling airport navigation light system - Google Patents
Method for controlling airport navigation light system Download PDFInfo
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- CN109661859B CN109661859B CN201880003437.7A CN201880003437A CN109661859B CN 109661859 B CN109661859 B CN 109661859B CN 201880003437 A CN201880003437 A CN 201880003437A CN 109661859 B CN109661859 B CN 109661859B
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- H—ELECTRICITY
- H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
- H05B—ELECTRIC HEATING; ELECTRIC LIGHT SOURCES NOT OTHERWISE PROVIDED FOR; CIRCUIT ARRANGEMENTS FOR ELECTRIC LIGHT SOURCES, IN GENERAL
- H05B47/00—Circuit arrangements for operating light sources in general, i.e. where the type of light source is not relevant
- H05B47/10—Controlling the light source
- H05B47/175—Controlling the light source by remote control
- H05B47/185—Controlling the light source by remote control via power line carrier transmission
Abstract
A method for controlling an airport navigation light system (22), the system comprising (a) a power supply (24) for generating an AC current (I); (b) a plurality of light units (26) powered by a power source (24) via a cable (25) and comprising a receiver; (c) at least one aviation ground light (14.1); and (d) a control unit (30) connected to the cable (25) and arranged for sending messages to and receiving messages from the luminaire unit (26) via the cable (25), the method comprising the steps of: (i) determining a noise level for a plurality of time slots (S) along a period of the AC current (I); (ii) determining a low noise time slot during which a noise level is below a noise threshold; (iii) sending low information messages (M) via cablelow) Encoding the timing of at least some of the low noise slots relative to the period; and, (iv) transmitting high information messages encoding control commands during these low noise time slots.
Description
Technical Field
The present invention relates to a method for controlling an airport navigation light system comprising (a) a power supply for generating an AC current, the AC current having a period; (b) a plurality of light fixture units powered by a power source via a cable and comprising a receiver and at least one aviation ground light; and (c) a control unit connected to the cable and arranged for sending and receiving messages to and from the luminaire unit via the cable. According to a second aspect, the invention relates to such an airport navigation light system.
Background
Such airport navigation light systems are known from FR 2865871 a1 and WO 95/24820 a1 and are used to illuminate traffic roads at airports, such as their runways or taxiways. The lights of airport navigational light systems, which may also be referred to as aviation floor lights, must be periodically checked to ensure that they are functioning properly. Furthermore, it is advantageous to be able to communicate with each of these lights so that they can be used as a signal for the pilot.
WO 95/24820 a1 discloses a "method and system for synchronizing a time slot to a portion of AC half cycle current", there being regions of AC half cycle current that are not used as time slots. This is based on the fact that the AC current is thyristor modulated, and according to the thyristor modulation technique, when the AC effective current value is increased by increasing the thyristor conduction angle, the previous region is reduced. Therefore, according to the prior art description, this region cannot be used for a slot. In contrast, the present invention defines a very short time slot to have multiple time slots (S) along the AC half cycle current, a method of detecting noise along the AC half cycle current, and a method of determining which time slot of the multiple can be activated to encode a message based on the noise information.
WO 95/24820 a1 communicates using a high frequency pulse signal, wherein the pulse signal comprises a plurality of pulses, and wherein each individual pulse is generated by influencing the impedance pulse by pulse during a time slot. Thus, there is no transmitter and each slot includes one bit.
WO 95/24820 a1 does not describe how to overcome the noise level along the time slot. Since reception is based on interference detection synchronized with the time slot, there seems to be little chance of avoiding any unexpected noise along the time slot due to the fact that transmission is done by affecting the impedance. Therefore, this prior art technique may lose communication if signal noise overlaps with the generated pulse. The power supply in an airport may be supplied from different phases of a three-phase grid and the cables may be unshielded and closely placed, if this is the case, each airport navigational light system will have distortion in its time slot. Because of the time slot SjCan be assigned in the quiet region of the AC half-cycle current, the present invention overcomes the limitations of the prior art WO 95/24820 a 1.
US 2008/0304577 a1 describes a method for power line communication in which a noise condition corresponding to a period of an AC current is detected. Based on these noise conditions, a plurality of communication channels in the time domain are generated, and tone maps used in these communication channels are prepared so that noise does not interfere with messages too strongly. In other words, a communication channel with a high noise level is used to transmit data requiring a lower quality of service. Those communication channels with a low noise level are used for e.g. voice over IP packets. The data rate ranges between 10 and 100 megabits per second. This approach is well suited for power line systems, for example in houses, but is not suitable for airport navigation light systems, since the achievable data rates are reduced by at least three orders of magnitude. A typical data rate that can be achieved in airport navigational light systems is about 0.002 megabits per second.
Some airport navigational light systems use unshielded cables to power the light units, where each light unit controls at least one aviation floor light. These existing systems can be upgraded to communicate with the light units. However, the number of aviation floor lights that can be individually addressed by these systems is quite limited.
All aerial floor lights and all light units may be connected to a network of shielded data cables. This will result in a secure, reliable and versatile system, but requires a completely new communication system.
Disclosure of Invention
The present invention is directed to improvements in airport navigational light systems, and in particular, to existing airport navigational light systems.
The invention solves this problem by a method having the features of claim 1. Specifically, the method comprises the following steps: (i) determining a noise level for a plurality of time slots (S) along a period of the AC current (I); (ii) determining low noise time slots during which the noise level is below, for example, a predetermined noise threshold; (iii) sending low information messages (M) via cablelow) A low information message encoding the timing of at least some, in particular all, of the low noise slots relative to the period; and (iv) transmitting high information messages encoding control commands only during these low noise time slots.
According to a second aspect, the invention solves the problem by an airport navigation light system as described above, wherein the control unit is arranged to automatically perform the steps of the method according to the invention.
One advantage of the present invention is the ability to control a number of aviation floor lights. Tests have shown that more than 500 and up to 990 lamps can be processed in less than 5 seconds per available frequency channel. As a result, airport navigation light systems for relatively large airports may be retrofitted.
Another advantage is a low error rate. Since only low noise time slots are used, frequency reuse is possible and errors in data transmission are unlikely.
Another advantage is that repeaters are generally not required. Since a plurality of time slots may be used, the maximum frequency can be chosen to be below e.g. 30 khz. The inventors have found that the signal attenuation is particularly high at higher frequencies. Repeaters are generally not needed because of the ability to use lower frequencies, with reasonably low attenuation.
As a result, the cable does not need to be shielded. The invention is applicable to almost all existing airport navigation light systems.
Another advantage of the present system is that it is robust. Since the luminaire unit and/or the control unit only use low noise time channels, the communication electronics can be switched off or set to automatically switch off during high noise time slots according to a preferred embodiment. Therefore, they are not affected by possible voltage peaks.
In this specification, noise level is specifically intended to mean the amount of undesirable current and/or voltage fluctuations.
The noise threshold is in particular intended to mean a fixed value that has been selected such that noise below the threshold does not interfere with the data transmission. The noise threshold may be predetermined. In other words, the noise threshold may be stored, for example, in a digital memory, prior to determining the noise level. The noise threshold is chosen to be as high as possible, but low enough to ensure reliable communication.
Alternatively, the noise threshold may be implicit. For example, the method may comprise the steps of: (a) determining the number of required time slots NaSo as to be able to obtain status information from the aviation ground lights within a preset time interval, for example 2 seconds or 5 seconds, and (b) select a status indicator havingThe first of the lowest noise levels. In this case, the noise threshold is higher than the noise level of the Na-th slot having the lowest noise level and the slot having the (Na +1) lowest noise level.
The phrase "along the cycle" is intended to mean a position relative to a repeating pattern of AC current. Instead of the phrase "along the cycle", the phrase "along the waveform of the AC current" or "waveform with respect to the AC current" may be used. The AC current can be described as
In other words, the AC current is a periodic function of time t. The phrase "along the period" refers to time modulo 2 π.
A time slot is intended to mean a defined time interval in a time schedule, i.e. a time interval relative to an AC current. In other words, a time slot is a time interval of a determined duration during which a resource (in the present case: the transmission capacity of the cable) can be used and wherein the time interval occurs periodically (in the present case: within a period or half period of the AC current).
Each light fixture unit is connected to at least one aviation ground light. It is possible, but not necessary, that the number of aircraft floor lights to which the light units are connected is constant for all light units.
Preferably, the low information message encodes less than two bits per half cycle, for example one bit per half cycle. Such low data rates make data transmission very robust and very error-prone.
Preferably, the high information message contains at least 12 bits per half cycle, for example 17, 18 or 19 bits per half cycle.
The width of the time slot is preferably at least 300 microseconds and/or at most 600 microseconds. There may be at least 20 time slots per cycle, in particular at least 30 time slots. Preferably, there are less than 60 time slots per cycle, in particular less than 50 time slots. The number of bits per active low noise slot is preferably at least 1, but multiple frequency channels are possible and advantageous. In particular, more than two, three or four frequency channels can be used. It has been shown that more than 9 frequency channels are possible, but are generally not required.
Preferably, the cable is unshielded. Of course, the invention can also be used for shielded cables. However, it may also be advantageous to use it with unshielded cables.
Step (iii) may comprise transmitting a low noise time slot mask. This is a continuous sequence of bits, where each bit encodes whether a slot is low noise and active. The time slots of the low noise time slots can be coded in different ways, but this is a very efficient way of doing this. It should be noted that encoding low noise slots can also be accomplished by encoding inactive or high noise slots such as those that are either low noise but unused or not low noise. In this case, communication occurs only in those time slots that are not marked as inactive or high noise.
The low noise time slots used to send high information messages are called active time slots. It is possible, but not necessary, that all low noise time slots are active time slots. If not all low noise time slots are necessary for communication with the luminaire unit, it is advantageous to use the fewest noisy time slots as active time slots.
According to a preferred embodiment, the bit value of each time slot and each frequency channel is frequency-coded or phase-coded. If the bit value is frequency encoded, a bit value of 0 is represented by a first frequency and a bit value of 1 is represented by a second frequency different from the first frequency. If the bit value is phase encoded, a bit value of 0 is represented by a first phase of frequency and a bit value of 1 is represented by a second phase of the first phase relative to frequency. In particular, the second phase is 180 °.
The first channel may be used to encode time critical information, e.g., whether the luminaire is operational, inactive or defective. The second channel may be used to encode non-time critical information, e.g. electrical parameters of the lighting unit, such as voltage or current. Preferably, the first channel uses frequencies having lower attenuation and/or noise levels than the other channels.
If the bit value is frequency encoded, the frequency is preferably sampled in the middle of each time slot, e.g. by the control unit and/or the luminaire unit. The phrase "in the middle of a time slot" is especially intended to mean a time interval near the center of the time slot, wherein the interval has an interval length of no more than one tenth of the time slot width.
Preferably, the frequency does not exceed 30 kilohertz. As noted above, higher frequencies can cause a lot of attenuation, thus requiring repeaters.
According to a preferred embodiment, for each time slot, at least four, in particular at least six, frequency channels are used. It has been shown that for most airport navigation light systems at least up to ten frequency channels are possible, which results in high data rates.
According to a preferred embodiment, at least some of the high information messages encode switching information for selectively switching at least one lighting unit on or off. The switching information may contain the point in time at which the respective luminaire unit has to be switched on or off. The time point may refer to an internal time or a system time allocated by the control unit, for example, via a reference point setting signal as described below.
Steps (i) to (iv) are preferably performed automatically by the control unit. Preferably, at least most of the light units automatically perform a method comprising the steps of: (i) receive a low information message encoding timing of the low noise time slots, and (ii) transmit at least one status message in at least one of the low noise time slots. Of course, the light units typically receive and send these types of messages on a regular basis.
Steps (i) to (iv) may be performed after the airport navigation light system is started. These steps may also be performed after a predetermined time interval, for example, once a day.
Preferably, steps (i) and (ii) of claim 1 are repeated after a preset time interval and if the noise level in a low noise slot exceeds the noise threshold and the low noise slot is an active low noise slot for transmitting high information messages, a new low information message is transmitted encoding the timing of at least some of said low noise slots relative to the period. If the noise level of one of the high noise time slots is below a noise threshold and the active low noise time slot has a higher noise level than the (preceding high noise) time slot, a new low information message may be sent encoding the timing of at least some of the low noise time slots relative to the period. In other words, the active low noise time slots will be changed if necessary and/or advantageous.
The waveform of the AC current may be a phase-cut sine wave or a sine wave, i.e. a complete sine wave, and has at least one current edge per cycle, in particular exactly two current edges, wherein the timing of the time slot is determined with respect to the current edges. This timing of the time slots is performed by the lighting units and/or the control unit. The current edge may be a point in time along the cycle of the AC current, which can be detected with the highest accuracy. Thus, timing miss matches between the control unit and the light unit or between two light units are small. Thus, a relatively small time slot can be used.
If the waveform of the AC current is a phase-cut sine wave, the current edge is sharply rising when the phase cut ends and sharply falling when the phase cut begins. If the waveform of the AC current is a sine wave, a current edge occurs when the first derivative with respect to time has its maximum or minimum.
Alternatively, the waveform of the AC current is a sine wave. Of course, cosine waves are equal to sine waves, since they differ only in phase. The timing of the time slots may be determined relative to the phase of the sine wave.
The method may comprise the steps of: by means of the clock of the luminaire unit, by sending a reference point setting signal, for example by means of the control unit; and determining the timing of the time slot by synchronizing the clock with the phase of the AC current based on the reference point setting signal. The reference point setting signal may include (i) a first set (e.g., 0) of at least one bit of the first value followed immediately by (ii) a flag bit (e.g., 1) that is not the first value, and (iii) a second set (e.g., 0) of at least one bit that is the first value. The luminaire unit preferably determines the sampling time point of the time slot relative to the flag bit time point of the flag bit. In other words, the point in time when the fixture unit receives the flag bit is considered as an important point in time for synchronizing the internal clock of the fixture unit with the AC current. The first set preferably comprises at least two consecutive equal bits. The second set preferably comprises at least two consecutive equal bits being the first value.
The phrase synchronizing the clock with the phase of the AC current based on the reference point setting signal is especially intended to mean that the point in time at which the reference point setting signal is received is used to calculate a time shift between the clock of the lighting unit and the AC current, wherein the frequency of the clock is stabilized to the frequency of the AC current.
An independent aspect of the invention is a method for controlling an airport navigation light system that includes (a) a power supply for generating an AC current, the AC current having a period; (b) a plurality of light fixture units powered by a power source through a cable and including a receiver and a clock; (c) a control unit connected to the cable and adapted to send and receive messages to and from the light unit via the cable, the method comprising the steps of: (i) sending a message in a time slot by at least one light unit; determining the timing of the time slot through a clock; (ii) the reference point setting signal is sent (e.g., by a control unit) and the clock is synchronized to the AC current based on the reference point setting signal.
An independent aspect of the invention is also an airport navigation light system that includes (a) a power supply for generating an AC current, the AC current having a period; (b) a plurality of light fixture units powered by a power source through a cable and including a receiver and a clock; (c) a control unit connected to the cable and configured to send and receive messages to and from the fixture unit via the cable, wherein (d) the fixture unit is configured to automatically send messages in time slots, wherein the timing of the time slots is determined by a clock; and wherein (e) the control unit is arranged to automatically send the reference point setting signal; and wherein (f) the luminaire unit is arranged to automatically synchronize the clock with the AC current (I) based on the reference point setting signal.
The method and the airport navigation light system, which may be part of an airport, may or may not have the features described in relation to other aspects of the invention and vice versa.
The airport navigation light system may include a filtering unit between the power supply and the light units. The filter unit is arranged to act as a short circuit for a first cut-off frequency, for example 32kHz, and for frequencies higher than a second cut-off frequency, which is lower than the first frequency, for example 2 kHz. The filtering unit may also be arranged such that frequencies above the second cut-off frequency are prevented from entering the power supply.
The voltage of the power supply is preferably at least 4 kv, preferably no more than 8 kv.
Each luminaire unit may comprise a transformer, a receiver, a transmitter and a processor.
According to a preferred embodiment, the luminaire unit is connected to the cable via an isolation transformer. Failure of one light bulb unit does not interrupt the entire system. Preventing very high frequencies from entering the lamp unit. If one of the bulb units is short-circuited to ground, this does not affect the other bulb units.
Preferably, there is one clock per lamp unit. The clock includes a frequency generator that is synchronized with the AC current. It is advantageous, but not necessary, that each luminaire unit has its own clock. Alternatively, two or more light units may share one clock.
The clock may comprise a phase locked loop with a low pass filter characteristic, e.g. a PI (proportional and integral term) controller. The timing of the current edges typically shows jitter with respect to the sinusoidal envelope of the AC current. The low pass filter characteristic may have a cut-off frequency that is selected to eliminate jitter, but to allow the clock to follow a drift of the current edges of the AC current with respect to the frequency generator. In other words, the clock follows the drift of the current edge synchronously, but not its jitter. For example, the present edge may be determined by determining a point in time at which the increase in the AC current over time (i.e. the first derivative of the current) exceeds a preset threshold. The low pass filter in the phase locked loop has the effect that the clock will run faster if the frequency of the AC current increases. The cut-off frequency may be 10 hz, in particular below 1 hz.
According to a preferred embodiment, the airport navigation light system has a number of aviation ground lights selected to be small enough so that the status of all light units is retrieved within two seconds. An airport may comprise more than one airport navigation light system according to the invention, enabling a larger total number of aviation floor lights that can be inspected in two seconds.
The present invention also solves this problem by an airport comprising an airport navigation light system, a taxiway and a runway as described above, wherein the aviation ground light is mounted in the taxiway and/or runway. According to a preferred embodiment, the airport comprises a second airport navigation light system as described above, wherein the frequency of the frequency channel in the first airport navigation light system is different from the frequency in the frequency channel in the second airport navigation light system such that cross-talk between the two airport navigation light systems is minimized.
It should be noted that an airport may comprise two groups of light units. The first group may be safety-related and may need to be checked within, for example, two seconds, the second group may not be safety-related and may only be checked within a longer period of time, for example, five seconds.
The airport may include (i) a second airport navigation light system according to the present invention; wherein (ii) the control units of the first airport navigation light system are synchronized with the second control units of the second airport navigation light system. At least one frequency of one of the frequency channels in the first airport navigational light system corresponds to one of the frequencies of one of the frequency channels in the second airport navigational light system. Therefore, crosstalk may occur. In order to avoid crosstalk, each luminaire unit has a digital memory in which the timing of the transmission time frames is stored, wherein the transmission time frames of all luminaire units of the first and second airport navigation light systems are different. Thus, even if there is crosstalk between the cables of the first airport navigation light system and the cables of the second airport navigation light system, the communication is not disturbed.
Drawings
The invention will now be described in more detail with reference to the accompanying drawings, in which,
FIG. 1 shows a schematic diagram of an airport according to the present invention;
FIG. 2 depicts a circuit diagram of an airport navigational light system that is part of the airport of FIG. 1;
FIG. 3 is a schematic diagram of a time slot for transmitting a high information message; and
fig. 4 shows a diagram for explaining the coding of the timing of the active low noise time slot and the reference point setting signal.
Detailed Description
Fig. 1 shows an airport 10 according to the present invention. The airport 10 includes a runway 12 and a plurality of air ground lights 14.1, 14.2, etc. that may be used for the runway or taxiway 16 or another portion of the airport infrastructure. The airport 10 may also include a tower 18 and at least one terminal 20.
Fig. 2 shows an airport navigation light system 22 comprising a power supply 24 for generating an AC current which powers the light units 26.1,26.2, …,26.N via a cable 25. The voltage U is, for example, 5kV and the frequency fAC50Hz or fAC60 Hz. The filter 28 is arranged between the power supply 24 and the lamp unit 26.i (═ 1,2,.., N).
For the first cut-off frequency fco132kHz and above a second cut-off frequency fco2At a frequency of 2kHz, the filter unit 28 acts as a short circuit between the first end E1 and the second end E2 of the cable 25. The filter unit 28 being above fco1Strongly attenuated. Lower than fco2Can hardly pass through the filter from the first terminal E1 to the second terminal E2. The filter unit 28 also prevents from rising above fco2Into the power supply 24.
The airport navigation light system 22 also includes a control unit 30, the control unit 30 being connected to the cable 25 via an isolation transformer 32. The control unit 30 may have a terminal or another human machine interface so that an operator can communicate with the light unit 26 using the control unit 30.
Each light unit 26.i is connected to the cable 25 and to at least one aviation ground light 14.i, e.g. 14.1, by an isolation transformer 34. i. No aviation floor light 14.i is connected to more than one light fixture unit 26. Fig. 2 shows these elements with i ═ 1. All the lamp units 26.i have the same structure. Each light fixture unit 26.i and the at least one aviation floor light 14.i connected to the light fixture unit 26.i are part of a light fixture system 36. i.
The lighting unit 26.i comprises a first frequency filter F1 for filtering out frequencies below the first frequency F1.1And higher than the second frequency f1.2(wherein f1.1<f1.2) All of the frequencies of (a). The luminaire unit 26.i may comprise a further frequency filter Fj(j-2, …, n) for filtering frequencies below the third frequency fj.1And higher than the second frequency fj.2(wherein fj.1<fj.2) All of the frequencies of (a). For each frequency filter FjWith its corresponding input connected to receiver 39. i. The receivers 39.i are connected to respective isolation transformers 34. i. The output of the frequency filter FJ is connected to a demodulator DEMj (j ═ 1, …, Nc). N is a radical ofcIs the number of frequency channels that can be used.
The demodulator DEMj is arranged to determine whether the first frequency f is presentj.1(which may be equal to bit value 0) or a second frequency fj.2(which may be equal to bit value 1).
The receiver 39.i is connected to a clock 41.i (41.1 in fig. 2) via at least one frequency filter Fj. The clock includes a frequency generator or oscillator 38.i, for example, a quartz oscillator and a Phase Locked Loop (PLL)40. i. Thus, the clock 41.i receives the frequency f of the AC current in the cable 25.iaAC. Thus, the oscillator 38.i is coupled to the AC frequency fACAnd (6) synchronizing.
All demodulators DEM1, 42.. DEMNc are connected to processor 42.1 (fig. 2: 42.1). The processor 42.i may comprise an fpga device (fpga, field programmable gate array). The processor 42.i is connected to the respective aircraft ground light 14.i (in the present case: the aircraft ground light 14.1), for example for switching it on and off.
The processor 42.i is also used to check the voltage and current through the aviation ground light 14.i in order to check whether the aviation ground light 14.i is functioning properly.
Processor 42 is programmed to automatically decode messages sent by control unit 30. For example, the control unit 30 may send a high information message MhighWhich codes the address of the corresponding aircraft floor light 14.i and codes the aircraft floor light 14.i has to be carried outThe corresponding command of the row. For example, high information message MhighMay encode information that a particular aviation ground light 14.i is turned on or off. Alternatively or additionally, the high information message may encode a command for the status of a particular aviation ground light 14.i sent by the respective controller. For this purpose, the processor is connected to a transmitter 44 for transmitting messages via the cable 25. High information message MhighIt is also possible that the code has to be used for MhighThe time slot of the response of (1).
Fig. 2 shows that the airport may include a second airport navigation light system 22'. It should be noted that the airport 10 may include two, three, or more airport ground lights systems, where no airport ground lights are connected to two or more airport navigation light systems at a given time.
The switch 43.1 is connected to the processor 42.1, the processor 42.1 being able to open and close the switch 43.1.
Fig. 3 is a schematic diagram for explaining the method according to the present invention. Fig. 3a shows the AC current I from the power supply 24 (see fig. 2). In this example, the AC frequency fACIs 50 Hz. Fig. 3a shows that the waveform of the AC current i (t) is a phase-cut sine wave. It includes a point in time t along the AC current cycleedge1Along 46 of the current.
FIG. 3b shows the noise level noise Ieff(t) which may be at the effective value of the noise current IeffIs measured. It can be seen that at tedge1Immediately after the current edge of (c), the noise level exceeds the noise threshold Ieff.thr. The time interval between the current edge 46 and the second current edge 46' may be referred to as a frame or time frame and is divided into, for example, 20 time slots. The time slots being relative to the current edge points in time t with respect to the periodedgeiThe time interval of (c). In this case, all time slots have the same width, i.e. duration. This is advantageous, but not necessary.
In this example, in time slot S1、S10And S11Medium noise IeffExceeding a noise threshold Ieff.thr. Therefore, they are not used for communication.
Fig. 3c schematically shows that within a time slot, e.g. time slot S2, a plurality of frequencies can be used to encode a bit value. This is well known as frequency reuse.
As shown in fig. 3b, because the noise level is below the noise threshold Ieff.thrThe time slots S2, S3, ·, S9, S12, and S20 may be used for communication. Here, the time slot S20 is not used. Determining a noise level and determining a time slot S in which the noise level is below a noise thresholdjIs performed by the control unit 30.
Fig. 4 shows a low information message M sent by the control unit 30 (see fig. 2)lowThe structure of (1). Low information message MlowIncluding codewords that may be 13 bits. It can be seen that the low information message MlowOne bit is encoded for each frame or each half cycle, which is equal to two bits per cycle. The codeword encodes the fact that the transmitted message is a low information message.
The codeword is followed by an active slot mask. This is an indication of time slot SjWhether it is an active bit value sequence. The active time slot is a low noise time slot for communication. Typically, all low noise time slots are active time slots. Since, in this example, S1Is a high noise time slot and the corresponding bit value is 0. Due to S2Is a low noise slot and has a bit value of 1. Of course, the bit values may be assigned in reverse.
In this example, only 20 slots S are usedj19 of the above. Thus, the active slot mask has 19 bits. The fact that only 19 of the 20 possible time slots are used is stored in the digital memory 21.i of the processor 42 (see fig. 2) and the corresponding digital memory of the control unit 30, for example.
In the digital memory 21.i, digital addresses are stored. The numerical address codes the transmission time frame for the lighting unit 26. A transmission time frame is a time frame in which only the respective luminaire unit 26.i is allowed (and will) transmit data.
After the active slot mask, a reference point setting signal is transmitted. The reference point setting signal uses a time slot as shown in fig. 3. The reference point setting signal comprises a first set R1 comprising at least 1 bit, in this example 4 consecutive equal bits, e.g. 0. The first set R1 is immediately followed by a flag bit B. Here, B is represented by a value of 1. The flag bit B is followed by a second set of at least 1 bits R2 of the first value, i.e. 0 in this example. The number of bits in the first set and in the second set may be predetermined. Alternatively, the low information message may include a further component that is sent immediately after the active slot mask and encodes the slot in which the marker bit is to be sent.
Since the marker bits have different bit values than the first set and the second set, the peaks of the respective signals determine the time slots along the cycle of the AC signal (in this example: S) with high accuracy6) The time position of (c). The processor 42 (see fig. 2) measures the time at which the processor detects the marker bit relative to its internal clock 38 and calculates the time shift at between the time of the clock 38 and the point in time at which the marker bit was received. Processor 42 calculates each slot S by a time consisting of a clock time and a time shiftjTo the intermediate position of (c).
Fig. 2 shows that the airport may include a second airport navigation light system 22' that has the same structure as the first airport navigation light system 22.
Its control unit 30' is synchronized with the control unit 30. The frequency used in the second airport navigational light system 22' is the same as the frequency used in the first airport navigational light system 22. In other words, all of the frequency channels in the first airport navigation light system 22 correspond to respective frequencies of the frequency channels in the second airport navigation light system 22'.
All the light fixture units 26.i of the first airport navigation light system 22 and all the light fixture units 26.i 'of the second airport navigation light system 22' have different transmission time frames. This ensures that at most one luminaire unit 26.i transmits data at any given time.
Fig. 1 shows that the aviation floor lights 14.i of the first airport navigation light system 22 and the aviation floor lights 14.i 'of the second airport navigation light system 22' are arranged in a complementary manner. In other words, they are arranged so that even if one of the airport navigation light systems 22, 22' fails, it is still possible to use, for example, the runway 12 and/or taxiways.
List of reference numerals
10 airport fACAC frequency
12 runway F1 first frequency filter
14 aviation ground lamp F2 second frequency filter
16 taxiway F3 third frequency filter
18 tower
i, j run index
20 terminal I AC current
21 digital memory IeffEffective value of noise current
22 airport navigation light system Ieff.thrNoise threshold
24 power supply matsmActive time slot mask
25 electric cable
26 Lamp Unit mrpssReference point setting signal
28 Filter MhighHigh information message
MlowLow information message
30 control unit N number of lamp units
Number of Nc frequency channels of 32 isolation transformers
34 isolation transformer
36 first set of luminaire systems R1
38 frequency generator, second set of oscillators R2
39 receiver S slot
time t
40 PLL tBMarking bit time points
41 clock UAC voltage
42 processor
43 switch
44 transmitter
46 current edge
B flag bit
DEM demodulator
First end of E1 cable
Second end of E2 cable
fl.1First frequency
fl.2Second frequency
Claims (14)
1. A method for controlling an airport navigation light system (22), the airport navigation light system comprising:
(a) a power supply (24) for generating an AC current (I);
(b) a plurality of lamp units (26), the plurality of lamp units (26)
-is powered by the power supply (24) via a cable (25), and
-comprising a receiver;
(c) at least one aviation ground light (14.1), wherein each light fixture unit (26) is connected to the at least one aviation ground light; and
(d) a control unit (30), the control unit (30)
-is connected to the cable (25), and
-arranged for sending messages to and receiving messages from said light unit (26) via said cable (25),
characterized in that the method comprises the following steps:
(i) determining a noise level of a plurality of time slots (S) along a cycle of the AC current (I), wherein the plurality of time slots (S) occur periodically within each cycle or half-cycle of the AC current (I);
(ii) determining a low noise time slot during which the noise level is below a noise threshold;
(iii) sending a low information message (M) via the cable by the control unit (30)low) A low information message encoding timing of at least some of the low noise slots relative to the period;
(iv) transmitting a high information message encoding a control command only during the low noise time slots; and
(v) setting a signal (m) by sending a reference point by means of a clock (41) of the lighting unit (26)rpss) (ii) a And determining the timing of the time slot by synchronizing the clock with a phase of the AC current based on the reference point setting signal.
2. The method of claim 1, wherein:
the low information message encodes less than two bits per half cycle.
3. The method of claim 2, wherein:
(a) the low information message (M)low) The method comprises the following steps:
(i) a code word being the low information message (M) for the messagelow) Is used to encode the information of (a) to (b),
(ii) an active time slot mask that follows the codeword, the active time slot mask encoding an active low noise time slot,
(iii) said active time slot mask is a continuous bit sequence, wherein each bit encodes whether a time slot is low noise and active, and
(iv) reference point setting signal (m)rpss) And an
(b) The luminaire unit (26) sets a signal (m) based on the reference pointrpss) A sampling time point for sampling the bit value is determined.
4. The method of claim 1, wherein:
(a) the reference point setting signal (m)rpss) Comprises that
-a first set (R1) of at least one bit of a first value followed by a first bit of a second value
-a flag bit (B) which is not said first value, and
-a second set (R2) of at least one bit being said first value, and
(b) a marker bit time point (t) of the lighting unit (26) relative to the marker bit (B)B) A sampling time point in a time slot (S) is determined.
5. The method of claim 2, wherein:
(a) said steps (i) to (iv) are performed automatically by said control unit (30); and
(b) at least a majority of the light fixture units (26) automatically perform a method comprising:
-receiving the low information message (M) encoding the timing of the low noise time slotlow)；
-transmitting at least one status message in at least one low noise time slot.
6. The method of claim 5, wherein:
(a) (iii) repeating said steps (i) and (ii) after respective preset time intervals; and
(b) if the noise level of one of the low noise slots exceeds the noise threshold, and
the low noise time slot is an active low noise time slot for transmitting high information messages,
sending a new low information message (M) encoding the timing relative to at least some of the low noise slots of the cyclelow) (ii) a And/or
(c) If the noise level of one of the high noise time slots is below the noise threshold (I)eff.thr) And is and
the active low noise time slot has a higher noise level than the time slot,
sending a new low information message (M) encoding the timing relative to at least some of the low noise slots of the cyclelow)。
7. The method of claim 1, wherein:
-the waveform of the AC current is a phase-cut sine wave or a sine wave and has at least one current edge (46, 46') per cycle; and
-determining the timing of the time slot with respect to the current edge (46, 46').
8. Method according to claim 2, characterized in that it comprises the following steps:
-transmitting a reference point setting signal (m) by the control unit (30) after transmitting the active time slot maskrpss)；
-measuring, by a processor (42) of the luminaire unit (26), a detection time of a flag bit relative to an internal clock (38) of the luminaire unit (26);
-calculating a time shift Δ t between the time of the clock (38) and a point in time at which the marker bit is received by the processor (42); and
-calculating each time slot S by a time consisting of a clock time and said time shiftjTiming of (2).
9. Method according to claim 2, characterized in that it comprises the following steps:
-sending a low information message containing a component to be sent immediately after the active slot mask and encoding the slot in which the marker bit is to be sent;
-transmitting a marker bit at the start of the time slot;
-measuring, by a processor (42) of the luminaire unit (26), a detection time of the flag bit relative to an internal clock (38) of the luminaire unit (26);
-calculating a time shift Δ t between the time of the clock (38) and a point in time at which the marker bit is received by the processor (42); and
-calculating each time slot S by a time consisting of a clock time and said time shiftjTiming of (2).
10. The method of claim 2, wherein the lighting units (26) each comprise a clock,
the method comprises the following steps:
(i) sending a message in a time slot by at least one of the light units (26); determining the timing of the time slot by a clock;
(ii) sending a reference point setting signal (m) by the control unit (30)rpss) And is and
synchronizing the clock with the AC current (I) based on the reference point setting signal.
11. An airport navigation light system (22) comprising:
(a) a power supply (24) for generating an AC current (I), the AC current (I) having a period;
(b) a plurality of lamp units (26), the plurality of lamp units (26)
-is powered by the power supply (24) via a cable, and
-comprising a receiver;
(c) at least one aviation floor light (14); and
(d) a control unit (30), the control unit (30)
-is connected to the cable (25), and
-arranged for sending a message (M) to the luminaire unit (26)high,Mlow)，
-and receiving a message from the luminaire unit (26) via the cable (25),
it is characterized in that the preparation method is characterized in that,
(e) the control unit (30) is arranged to automatically perform a method comprising the steps of:
(i) determining a noise level for a plurality of time slots (S) along the period of the AC current (I);
(ii) determining a low noise time slot during which the noise level is below a noise threshold;
(iii) sending a low information message (M) via said cablelow) A low information message encoding timing of at least some of the low noise slots relative to the period;
(iv) transmitting a high information message encoding a control command only during the low noise time slots; and
(v) setting a signal (m) by sending a reference point by means of a clock (41) of the lighting unit (26)rpss) (ii) a And determining the timing of the time slot by synchronizing the clock with a phase of the AC current based on the reference point setting signal.
12. The airport navigation light system (22) of claim 11,
-the airport navigation light system (22) comprises at least one clock (41);
-there is a clock (41) for each lighting unit (26);
-the clock (41) comprises a frequency generator (38), the frequency generator (38) being phase locked to the AC current (I).
13. An airport (10) comprising
(i) A first airport navigation light system (22), said first airport navigation light system (22) being an airport navigation light system as defined in claim 12; and
(ii) a taxiway (16) and a runway (12),
(iii) wherein the aviation ground light (14) is mounted in the taxiway (16) or the runway (12),
(iv) a second airport navigation light system (22'), said second airport navigation light system (22') being in accordance with one of the preceding claims,
(v) the frequency of the frequency channel in the first airport navigation light system (22) is different from the frequency of the frequency channel in the second airport navigation light system (22').
14. The airport of claim 13, comprising:
(i) a second airport navigation light system (22') as claimed in one of the preceding claims;
(ii) the control unit (30) of the first airport navigation light system (22) is synchronized with a second control unit (30') of the second airport navigation light system (22');
(iii) wherein at least one of the frequencies of one of the frequency channels in the first airport navigation light system (22) corresponds to one of the frequencies of one of the frequency channels in the second airport navigation light system (22');
(iv) wherein each lighting unit (26.i) has a digital memory (21.i) in which the timing of a transmission time frame is stored, wherein the transmission time frames of all lighting units (26) of the first airport navigation light system (22) and the second airport navigation light system (22') are different.
Applications Claiming Priority (3)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| EP17166891.6 | 2017-04-18 | ||
| EP17166891.6A EP3393212A1 (en) | 2017-04-18 | 2017-04-18 | A method for controlling an airport navigation lights system |
| PCT/EP2018/059769 WO2018192920A1 (en) | 2017-04-18 | 2018-04-17 | A method for controlling an airport navigation lights system |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN109661859A CN109661859A (en) | 2019-04-19 |
| CN109661859B true CN109661859B (en) | 2021-06-01 |
Family
ID=58671363
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201880003437.7A Active CN109661859B (en) | 2017-04-18 | 2018-04-17 | Method for controlling airport navigation light system |
Country Status (6)
| Country | Link |
|---|---|
| EP (2) | EP3393212A1 (en) |
| CN (1) | CN109661859B (en) |
| ES (1) | ES2894695T3 (en) |
| PL (1) | PL3473062T3 (en) |
| PT (1) | PT3473062T (en) |
| WO (1) | WO2018192920A1 (en) |
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-
2017
- 2017-04-18 EP EP17166891.6A patent/EP3393212A1/en not_active Withdrawn
-
2018
- 2018-04-17 PL PL18716643T patent/PL3473062T3/en unknown
- 2018-04-17 ES ES18716643T patent/ES2894695T3/en active Active
- 2018-04-17 CN CN201880003437.7A patent/CN109661859B/en active Active
- 2018-04-17 EP EP18716643.4A patent/EP3473062B1/en active Active
- 2018-04-17 PT PT187166434T patent/PT3473062T/en unknown
- 2018-04-17 WO PCT/EP2018/059769 patent/WO2018192920A1/en unknown
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| WO1995024820A1 (en) * | 1994-03-11 | 1995-09-14 | Airport Technology In Scandinavia Ab | Communication on a series cable |
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Also Published As
| Publication number | Publication date |
|---|---|
| CN109661859A (en) | 2019-04-19 |
| PT3473062T (en) | 2021-10-19 |
| ES2894695T3 (en) | 2022-02-15 |
| WO2018192920A1 (en) | 2018-10-25 |
| PL3473062T3 (en) | 2021-12-27 |
| EP3473062A1 (en) | 2019-04-24 |
| EP3393212A1 (en) | 2018-10-24 |
| EP3473062B1 (en) | 2021-08-11 |
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