This invention relates to wireless vehicular sensor networks, in particular, to the reporting of the waveforms of these sensors due to the presence of motor vehicles.
There are some wireless sensor networks able to report that a motor vehicle passed near a vehicle sensor, but they cannot report the waveform of the vehicle sensor. Such networks can be used for counting the traffic passing near the vehicle sensor, but they are unable and/or difficult to use in other applications. By way of example, they cannot report the presence of a vehicle waiting for a traffic signal to change, because the vehicle has not necessarily passed the vehicle sensor. Consequently, they may be of little or no use for traffic signal control systems. What is needed is a method and apparatus for wireless vehicular sensor networks able to detect the presence of a motor vehicle whether or not the vehicle passes the sensor node.
Today, there are many parking facilities and controlled traffic regions where knowing the availability of parking spaces on a given floor or region would be an advantage, but costs too much to implement. Again, there is a central need to sense when a vehicle is present but not necessarily unmoving.
Today, many parking facilities and controlled traffic regions must identify and log vehicles upon entry and exist. This process is expensive, often requiring personnel. Wireless vehicular sensor networks unable to report the vehicular sensor waveform are much more complicated to deploy, the vehicular sensors must be placed to insure that the vehicle has passed a vehicular sensor to trigger identifying and logging the vehicle. What is needed are inexpensive mechanisms providing the vehicular sensor waveforms, supporting this service. What is needed are low cost, reliable mechanisms for monitoring entry and exit from these facilities and regions using these wireless vehicular sensor networks.
Today, many traffic authorities use a radar based velocity detection approach to apprehend motorists driving vehicles at illegal speeds. These radar based systems are relatively inexpensive, but are detectable by culprits who equip their vehicles with radar detection devices. Consequently, the motorists who traffic authorities most want to penalize, often avoid detection of their illegal activities. While alternative optical speed detection systems exist, they have proven very expensive to implement. What is needed is a low cost, reliable mechanism for vehicle velocity detection identifying the vehicle violating the traffic laws.
The invention reports at least one waveform characteristic of a vehicular sensor waveform in a wireless vehicular sensor network. The vehicular sensor waveform is the result of a vehicle passing near a wireless vehicular sensor node. The waveform characteristic may be the rising edge, the falling edge, the waveform duration, the waveform midpoint, the rising edge slope, the falling edge slope, number of zero crossings and/or number of zero crossings of the time derivative of the vehicular sensor waveform. Preferably, the events are reported in terms of a synchronized timing of rising edges and falling edges.
In a parking facility, where many vehicles remain stationary for extended periods of time, reporting the waveform duration or alternatively, the waveform midpoint, may preferably indicate that vehicle is parked. Alternatively, in traffic control situations such as shown in, reporting the rising edge and/or falling edge can help indicate length of a vehicle, which can further help in estimating vehicle velocity. Basically, upon reporting any two of the rising edge, the falling edge, the waveform midpoint, and the waveform duration, the velocity and length of the vehicle can be estimated, which is important in traffic control applications.
Transmitting the report uses at least one wireless physical transport. The wireless physical transport may include any of an ultrasonic physical transport, a radio-frequency physical transport, and/or an infrared physical transport.
The transmitting the report may be spread across a frequency band of the wireless physical transport. More particularly, the transmitting the report of the vehicular sensor waveform may include a chirp and/or a spread spectrum burst across the frequency band.
The report may further identify the wireless vehicular sensor node originating the report. The report may be relayed through an intermediate wireless node, which may or may not be a wireless sensor node. The identification may preferably be determined by when the vehicular sensor node transmits the report.
Transmitting the report of the vehicular sensor waveform may initiate a response across the wireless physical transport, preferably from an access point. The response may be an acknowledgement of receiving the report.
The wireless physical transport may also be used to send a synchronization signal to the wireless vehicular sensor nodes. The wireless vehicular sensor nodes may each maintain a local clock, synchronized by the clock synchronization sent across the wireless physical transport.
The report of the vehicular sensor waveform may be encoded in a packet format, which may be modulated and frequency converted. More than one vehicular sensor waveforms may preferably be encoded into one packet. The packets may be transmitted using a wireless communication protocol over the wireless physical transport. The acknowledgement and/or the synchronization message may be encoded in a packet. If the acknowledgement is not received by the vehicular sensor node, the next report preferably appends any new waveform characteristics to the report.
The transmitting of the report of the vehicle sensor waveform may preferably create a received vehicular sensor waveform report from the wireless vehicular sensor node, which may preferably be received by an access point in a wireless vehicular sensor network. The wireless vehicular sensor network may include more than one access point. The wireless vehicular sensor network may include a sensor report analyzer creating any of a vehicular traffic report, a vehicular parking report, and/or a vehicular speeding report, based upon the received vehicular sensor waveform report. The sensor report analyzer may be implemented in an access point. Alternatively, the sensor report analyzer may receive the received vehicular sensor waveform report from the access point. The received vehicular sensor waveform report may further include an indication of the wireless vehicular sensor node at which the vehicular sensor waveform originated.
The wireless vehicular sensor node may further preferably include: means for maintaining the clock count to create the task trigger and the task identifier. And means for operating the radio transceiver and the vehicular sensor based upon the task identifier, when the task trigger is active.
The wireless vehicular sensor node may further preferably include means for controlling the power from the power source delivered to the radio transceiver and the vehicular sensor based upon the task trigger and the task identifier.
One or more computers, field programmable logic devices, and/or finite state machines may be included to implement these means.
The means for controlling the power may preferably minimize delivery of power to preferably all circuitry when the task trigger is inactive, or the task identifier does not indicate the need for the circuitry, where the circuitry includes the transmitter and/or transceiver, the vehicular sensor, the computer, as well as other circuits, such as memory. The power consumption of the minimized circuitry may preferably be less than 100 micro-watts (μw), further preferably less than 30 μw. The means for maintaining the clock count may be powered most of the time. The means for maintaining may couple with a clock crystal. The clock crystal may preferably operate at approximately 32K Herz (Hz), where 1K is 1024.
At least two of the means for maintaining, the means for controlling, and the means for operating may preferably be housed in a single integrated circuit. Preferably, all three means may be housed in the single integrated circuit. Also, the single integrated circuit may house the transmitter and/or the transceiver and/or the vehicular sensor. The wireless vehicular sensor node may include an antenna coupled with the transmitter and/or the transceiver. The antenna may preferably be a patch antenna.
The power source, may preferably include at least one battery, and may further preferably include at least one solar cell.
The vehicular sensor may preferably use a form of the magnetic resistive effect. The vehicular sensor preferably includes a more than one axis magneto-resistive sensor to create a vehicle sensor state. The vehicular sensor may preferably include a two axis magneto-resistive sensor and/or a three axis magneto-resistive sensor.
The radio transceiver preferably implements a version of at least one wireless communications protocol, preferably the IEEE 802.15.4 communications standard. It uses at least one channel of the wireless communication protocol. It may use a second channel to communicate with a vehicle radio transceiver associated and/or attached to the vehicle.
The wireless vehicular sensor node may further include a light emitting structure, used to visibly communicate during installation and/or testing a vehicular sensor network.
This invention relates to wireless vehicular sensor networks, in particular, to the reporting of the waveforms of these sensors due to the presence of motor vehicles. The presence of a motor vehicle will refer to its presence whether stationary and/or in motion relative to the vehicular sensor node. By way example, an automobile passing near a vehicular sensor node at 20 Kilometers Per Hour (kph) will have a presence. That same automobile parked near a second vehicular sensor node will also have a presence. The invention reports at least one waveform characteristic of a vehicular sensor waveform in a wireless vehicular sensor network. The vehicular sensor waveform is the result of a vehicle passing near a wireless vehicular sensor node. The waveform characteristic may be the rising edge, the falling edge, the waveform duration, the waveform midpoint, the rising edge slope, the falling edge slope, the number of zero crossings, and/or the number of zero-crossings of the time derivative of the vehicular sensor waveform.
Often, the vehicle sensor state 104, when collected over time 102, is more chaotic, as shown in
The vehicle sensor state 104 may vary quickly in sign, even while one vehicle is passing near the vehicular sensor 2. Also confusing the picture, a second vehicle passing soon after the first vehicle may quickly stimulate the vehicular sensor 2 a second time 162.
The invention includes a method of conditioning the vehicle sensor state 104, collected over time by the following operations. Rectifying the vehicle sensor state 104 of
This method of signal conditioning may or may not use additional memory to perform its operations. It removes false positives caused by the isolated spike 160. It also removes false positives caused by the vehicle sensor state 104 varying in sign while one vehicle passes near the vehicular sensor 2.
The up-threshold 134 is often preferred to be larger than the down-threshold 136. The up-threshold is preferred to be about 40 milli-gauss. The down-threshold is preferred to be about 22 milli-gauss. These values for the up-threshold and the down-threshold are typical for North America, and may be calibrated differently elsewhere. The holdover-interval 138 is often preferred between 10 milliseconds (ms) and 300 ms. The units of the up-threshold and down-threshold are in the units of the vehicular sensor 2. The units of the holdover-interval are preferably in terms of time steps of a time division multiplexing scheme controlled by synchronization with the access point 1500 preferably acting to synchronize each wireless vehicular sensor node 500 in the wireless vehicular sensor network 1600. Often these units may be preferred to be in terms of 1/1024 of a second, or roughly 1 ms.
The wireless vehicular sensor node 500 may further preferably include: means for maintaining the clock count to create the task trigger and the task identifier. The means for operating 140 the transceiver 20 and means for using 100 are directed by the task identifier 34, when the task trigger 38 is active.
One or more computers, field programmable logic devices, and/or finite state machines may be included to implement these means.
Some of the following figures show flowcharts of at least one method of the invention, which may include arrows with reference numbers. These arrows signify a flow of control, and sometimes data, supporting various implementations of the method. These include at least one the following: a program operation, or program thread, executing upon a computer; an inferential link in an inferential engine; a state transition in a finite state machine; and/or a dominant learned response within a neural network.
The operation of starting a flowchart refers to at least one of the following. Entering a subroutine or a macro instruction sequence in a computer. Entering into a deeper node of an inferential graph. Directing a state transition in a finite state machine, possibly while pushing a return state. And triggering a collection of neurons in a neural network. The operation of starting a flowchart is denoted by an oval with the word “Start” in it.
The operation of termination in a flowchart refers to at least one or more of the following. The completion of those operations, which may result in a subroutine return, traversal of a higher node in an inferential graph, popping of a previously stored state in a finite state machine, and return to dormancy of the firing neurons of the neural network. The operation of terminating a flowchart is denoted by an oval with the word “Exit” in it.
A computer as used herein will include, but is not limited to, an instruction processor. The instruction processor includes at least one instruction processing element and at least one data processing element. Each data processing element is controlled by at least one instruction processing element.
The program system 200 of
The program system 200 of
The operation 202 of
By way of example, suppose a vehicle 6 approaches the wireless vehicular sensor node 500. The vehicular sensor state 104 is used to update the vehicle sensor state queue 122, as supported by operation 230 of
To continue the example, suppose the vehicle 6 moves away from wireless vehicular sensor node 500 at a later time. The operations of
The operation 204 of
The operation 212 of
The operation 236 of
The operation 232 of
The wireless vehicular sensor node 500 includes a vehicular sensor 2, which preferably includes a magnetic sensor, preferably having a primary sensing axis 4 for sensing the presence of a vehicle 6, as shown in
Transmitting the report uses at least one wireless physical transport. The wireless physical transport may include any of an ultrasonic physical transport, a radio-frequency physical transport, and/or an infrared physical transport.
Transmitting the report may be spread across a frequency band of the wireless physical transport. More particularly, the transmitting the report of the vehicular sensor waveform may include a chirp and/or a spread spectrum burst across the frequency band.
The transmitter 22 of
The report 120 of the vehicular sensor waveform106 may further identify the wireless vehicular sensor node 500 originating the report.
Transmitting the report of the vehicular sensor waveform may initiate a response across the wireless physical transport, preferably from an access point. The response may be an acknowledgement of receiving the report.
Consider the following example of a wireless vehicular sensor network 1600 including an access point 1500 and multiple wireless vehicular sensor nodes as shown in
In certain applications, such as sensing a vehicle 6 in parking slots within parking structures, the frame time period may preferably approximate multiple seconds, such as eight seconds. The meta-frame time period may be sixty times the frame time period, representing four minutes. The time slot period may be the frame time period divided by 1K, approximating one hundredth of a second.
The wireless physical transport may also be used to send synchronization signal to the wireless vehicular sensor nodes. The wireless vehicular sensor nodes may each maintain a local clock, synchronized by the clock synchronization sent across the wireless physical transport.
The report of the vehicular sensor waveform may be encoded in a packet format, which is modulated and frequency converted. More than one vehicular sensor waveforms may be encoded into one packet. The packets may be transmitted using a wireless communication protocol over the wireless physical transport. The acknowledgement and/or the synchronization message may be encoded in a packet.
The transmitting of the report 130 of the vehicular sensor waveform 106 may preferably create a received report 130 from the wireless vehicular sensor node 500, which may preferably be received by an access point 1500 in a wireless vehicular sensor network 1600 as shown in
The means for controlling 310 the power may preferably minimize delivery of power to preferably all circuitry when the task trigger is inactive or the task identifier does not indicate the need for the circuitry. The circuitry includes the transmitter 22 and/or transceiver 20, the vehicular sensor 2, the computer 10, as well as other circuits, such as memory 30. The power consumption of the minimized circuitry may preferably be less than 150 microwatts (μw). The means for maintaining 300 the clock count 36 may be powered most of the time. The means for maintaining may couple with a clock crystal. The clock crystal may preferably operate at approximately 32K Hertz (Hz), where 1K is 1024.
At least two of the means for maintaining 300, the means for controlling 310, the means for using 100 and the means for operating 140 may preferably be housed in a single integrated circuit. Preferably, all of these means may be housed in the single integrated circuit. Also, the single integrated circuit may house the transmitter 22 and/or the transceiver 20 and/or the vehicular sensor 2.
The power source 60, may preferably include at least one battery 64, and may further preferably include at least one solar cell 66.
The transmitter 22 and/or the transceiver 20 preferably implement a version of at least one wireless communications protocol, preferably the IEEE 802.15.4 communications standard. It uses at least one channel of the wireless communication protocol. It may use a second channel to communicate with a vehicle transceiver 8 associated attached to the vehicle 6, as shown in
The invention may preferably include a circuit apparatus 509 shown in
The transceiver 20 preferably implements a version of at least one wireless communications protocol, preferably the IEEE 802.15.4 communications standard. It uses at least one channel of the wireless communication protocol. It may use a second channel to communicate with a vehicle radio transceiver associated attached to the vehicle.
The wireless vehicular sensor node 500 may further include a light emitting structure, which is not shown, used to visibly communicate during installation and/or testing a vehicular sensor network. It may also include a second light emitting structure used to communicate with vehicle operators.
The invention includes an internal power system in the wireless vehicular sensor node 500. The power source 60 preferably includes at least one battery 64. The power source 60 may further preferably include at lease one solar cell.
The wireless vehicular sensor node 500, where the transceiver 20 may include a receiver and a transmitter. The power control operations when the transceiver power trigger is asserted, the transceiver power is set to operate the radio transceiver may further preferably include: When the transceiver-receive power trigger is asserted, the transceiver power is set to operate the receiver. When the transceiver-transmit power trigger is asserted, the transceiver power is set to operate the transmitter.
In certain preferred embodiments of the wireless vehicular sensor node 500, the radio transceiver may use a second of the channels of the wireless communication protocol to communicate with a vehicle radio transceiver 8 associated with the vehicle 6 as shown in
The invention includes a method of making a wireless vehicular sensor node 500 from the circuit apparatus 509 and from a plastic shell 510 as shown in
The plastic shell 510 may resiliently deform while preserving the glued bond 552 when the vehicle 6 rests 556 on the plastic shell 510. The vehicle may further rest on the plastic shell for more than a day, an hour, a minute, and/or a second.
The protective shell 570 may include a ring of rigid material, often preferred to be metal, to provide side support in certain instances for the plastic shell 510.
The filler 530 preferably includes an elastomer, which further preferably includes a polyurethane elastomer.
The gluing 542 and/or 546 preferably use an adhesive, which preferably does not destructively interact with the plastic shell 510, and may further be manufactured by Harding Systems.
The invention includes a method of using the power source 60 of
Distributing the power 62 from the power source 60 preferably includes delivering the transceiver power 74 to the transceiver 20, when the task identifier 34 indicates that the radio transceiver is used. And delivering a sensor power 80 to the vehicular sensor 2, when the task identifier indicates the vehicular sensor is used.
The method of using the power source 60 may preferably further include providing a constant power 72 to the clock timer 22.
The method of using the power source 60 may preferably further include: providing the computer power 76 to the computer 10, when a task trigger 38 generated by the clock timer 22 is asserted, the computer power is set to operate the computer. It may be further preferred that when a power-down command is asserted in the task identifier 34, the computer power is set to standby mode for the computer.
The invention includes an access point 1500 for wireless communicating 2202 with at least one the wireless vehicular sensor node 500 as shown in
The operations of the access point 1500 may be implemented by the second program system 1200, which may preferably include the following. When the second task identifier 1034 indicates distribute clock alignment, using the second clock count 1036 to create the global clock count 52, and using the second radio transceiver 1020 to send the global clock count to at least one wireless vehicular sensor node 500. When the second task identifier indicates access sensor state of the wireless vehicular sensor node, using the second radio transceiver to receive the report 130 from the wireless vehicular sensor node. When the second task identifier 1034 indicates calculate a vehicle velocity estimate 1054, calculating the vehicle velocity estimate based upon the received report 130. When the second task identifier 1034 indicates a traffic network update, generating a traffic report based upon the received report, and sending the traffic report using the network transceiver 1060 across the network-coupling 2502 to the traffic monitoring network 2500.
The invention includes installing the wireless vehicular sensor node 500 wireless communicating 2202 with an access point 1500, as shown in
The traffic flow zone 2000 may include more than one primary traffic flow 2002, often indicating two-way traffic. The traffic monitoring zone 2200 may include more than one traffic flow zone 2000.
The access point 1500 may wirelessly communicate with more than one wireless vehicular sensor node 500. By way of example,
The first traffic flow zone 2000-1 includes a first primary traffic flow 2002-1. A first-first wireless vehicular sensor node 500-1,1 and a first-second wireless vehicular sensor node 500-1,2 are installed in the first traffic flow zone 2000-1. The primary sensing axis 4 of these wireless vehicular sensor nodes are aligned with the first primary traffic flow 2002-1.
The second traffic flow zone 2000-2 includes a second primary traffic flow 2002-2. A second-first wireless vehicular sensor node 500-2,1 and a second-second wireless vehicular sensor node 500-2,2 are installed in the second traffic flow zone. The primary sensing axis 4 of these wireless vehicular sensor nodes are aligned with the second primary traffic flow.
The access point 1500 may integrate the number of vehicles sensed by a collection of wireless vehicular sensor nodes to estimate availability of parking in a parking facility, or a region of the parking facility. The traffic report 1056 may include the estimated availability. The traffic monitoring network 2500 may present the estimated availability to a vehicle 6 trying to park. The vehicle may be operated by a human operator or directed by an automatic driving system.
When a first vehicle 6-1 travels in the first primary traffic flow 2002-1 of the first traffic flow zone 2000-1, the following operations are performed by the first-first wireless vehicular sensor node 500-1,1 and the first-second wireless vehicular sensor node 500-1,2 are installed in the first traffic flow zone 2000-1. Both of the wireless vehicular sensor nodes are time synchronized by the access point 1500 to within a fraction of a second, in particular, to within sixty microseconds. The vehicle sensor state 32 of the vehicular sensor 2 of each of the wireless vehicular sensor node 500 with the wireless vehicular sensor nodes is used to create a vehicle sensor state 50 within that wireless vehicular sensor node. The first-first wireless vehicular sensor node 500-1,1 sends its vehicle sensor state 50 to at least partly create the received vehicular sensor state 1050. The first-second wireless vehicular sensor node 500-1,2 sends its vehicle sensor state 50 to further at least partly create the received vehicular sensor state 1050.
It is often preferred that the received vehicular sensor state 1050 includes a time synchronized sensor state for each vehicular sensor in the wireless vehicular sensor nodes for the same traffic flow zone. One preferred method of determining a vehicle velocity estimate 1054 includes using at least two vehicle sensor nodes, such as the first-first wireless vehicular sensor node 500-1,1 and the first-second wireless vehicular sensor node 500-1,2 of
The access point 1500 preferably includes a network transceiver 1060, which may have several preferred embodiments. The network transceiver 1060 may include only a network transmitter. Alternatively the network transceiver 1060 may include the network transmitter and a network receiver.
The traffic monitoring network 2500 may include a traffic control cabinet. The traffic control cabinet may include a NEMA traffic controller, a type 170 controller, or a type 2070 controller. The network transceiver 1060 may interface to a relay drive contact, through an opto-isolation circuit, or through an interface printed circuit board, which may support two relay drive contacts.
In
Alternatively, the traffic monitoring network 2500 may implement another embodiment of the network-coupling 2502. The network-coupling 2502 may include a wireline communications protocol. The wireline communications protocol may include at least one of the following: RS-232, RS-485, and a version of Ethernet possibly further supporting a version of High level Data Link Control (HDLC). The traffic monitoring network may support a TS-2 application layer on top of the RS-485 network layer. This application layer may support 19,200 to 600,000 bits per second transfer rates.
The access point 1500 may further include a video camera 1066 video-coupled 1064 with the second computer 1010, as shown in
Alternatively, the second memory 1030 may include a non-volatile memory component, which may store the traffic report. The non-volatile memory component storing the traffic report may reside in a removable memory device. Alternatively, the second wireless vehicular sensor node 5000 may include a socket for a removable memory device. Traffic reports may be collected, by inserting a removable memory device in the socket, and transferring them to the removable memory device.
The video camera 1066 may be used to identify the vehicle 6 entering and/or leaving a parking structure or reserved entry area. Each time the access point 1500 determines the entry of a new vehicle in a traffic flow zone 2000, the video camera 1066 may be triggered to photograph the license plate 9. With an overall system strobe of once every millisecond, there is a highly probable, perceptible gap between vehicles entering or leaving.
The preceding embodiments provide examples of the invention and are not meant to constrain the scope of the following claims.
This application is also a continuation in part of U.S. application No. 60/630,366, filed Nov. 22, 2004, which claims priority to Provisional Patent Application Ser. No. 60/549,260, filed Mar. 1, 2004 and Provisional Patent Application Ser. No. 60/630,366, filed Nov. 23, 2004, all of which are incorporated herein by reference.
Number | Name | Date | Kind |
---|---|---|---|
4361202 | Minovitch | Nov 1982 | A |
5491475 | Rouse et al. | Feb 1996 | A |
5648904 | Scott | Jul 1997 | A |
5748108 | Sampey et al. | May 1998 | A |
5859415 | Blomqvist et al. | Jan 1999 | A |
5877705 | Sampey | Mar 1999 | A |
5880682 | Soulliard et al. | Mar 1999 | A |
6016109 | Yosida et al. | Jan 2000 | A |
6208268 | Scarzello et al. | Mar 2001 | B1 |
6559774 | Bergan et al. | May 2003 | B2 |
6662099 | Knaian et al. | Dec 2003 | B2 |
6781523 | Matsui et al. | Aug 2004 | B2 |
6825778 | Bergan et al. | Nov 2004 | B2 |
6885311 | Howard et al. | Apr 2005 | B2 |
7382238 | Kavaler | Jun 2008 | B2 |
7382281 | Kavaler | Jun 2008 | B2 |
7382282 | Kavaler | Jun 2008 | B2 |
7388517 | Kavaler | Jun 2008 | B2 |
7391339 | Howard et al. | Jun 2008 | B2 |
7515997 | Imai | Apr 2009 | B2 |
20020145541 | Matsui et al. | Oct 2002 | A1 |
20020177942 | Knaian et al. | Nov 2002 | A1 |
20060097894 | Kavaler | May 2006 | A1 |
20060132298 | Kavaler | Jun 2006 | A1 |
20060202863 | Kavaler | Sep 2006 | A1 |
Number | Date | Country | |
---|---|---|---|
20060109104 A1 | May 2006 | US |
Number | Date | Country | |
---|---|---|---|
60630366 | Nov 2004 | US | |
60549260 | Mar 2004 | US |