Patent Grant
7382238
This invention relates to wireless vehicular sensor nodes used in wireless vehicular sensor networks, in particular, to the wireless vehicular sensor nodes reporting waveforms approximating the raw sensor readings due to the presence of motor vehicles and describing ambient conditions in the vicinity of the wireless vehicular sensor node.
Today, there are numerous situations in which confirming the type of vehicle passing over a spot on the road is important. While visual inspections can provide a good deal of information, they do not readily report the magnetic signature of a vehicle, which can reveal additional details about the vehicle contents. Methods are needed for determining that magnetic signature in a cost effective and reliable manner.
The situation has some significant hurdles. Running wires to sensors embedded in roadways turns out to be difficult, expensive, and often unreliable in the rugged environment of a roadway with multiple ton vehicles rolling over everything on a frequent basis. What is needed is a way to use a wireless vehicular sensor node to report something approximating the raw vehicular sensor waveform via wireless communications.
Wireless vehicular sensor networks often use repeaters and/or some of the vehicular sensor nodes to wirelessly convey wireless messages from distant sensor nodes to where they are collected, which will be referred to herein as intermediate nodes. These intermediate nodes are usually essentially invisible to the network, but add a significant delay to the time from the sending of the messages, and their reception at the collection node. Additionally, a wireless vehicular sensor network may not provide a ready mechanism to time synchronizing these messages, making it difficult form an accurate picture of the magnetic signatures of the sensor state of these systems taken as a whole. What is needed are methods and mechanisms supporting the time synchronization of these reports which allows a view of the system state at a given moment to be assembled.
There are additional problems which cannot be currently addressed. In many areas, it would be very useful to know the ambient conditions at the wireless vehicular sensor nodes. For example, a change from 100 degrees Fahrenheit to 50 degrees or from twenty percent to 90 percent relative humidity can indicate that the transmission properties of the air have changed, potentially altering the interpretation of the received waveforms being reported. Today, there are no wireless vehicular sensor nodes capable of reporting such ambient conditions.
In places where snow and ice can occur, it is often important to know if and where ice can form, and for how long. In places where intense rain may occur, it is often important to know how much water is standing on or near a roadway. What is needed are cost effective methods and mechanisms for the wireless vehicular sensor node to provide such ambient condition reports and for a traffic or public service portal to use those reports to create road condition reports, which can collectively improve the public welfare of their community by providing a network of remote sensors that can provide a real time maps to snow and ice conditions, standing water, and fog estimates.
The invention includes a circuit apparatus for a wireless vehicular sensor node, including the following.
The circuit apparatus may further include the following.
The invention's circuit apparatus, wherein the means for using, and the means for operating, and the means for sensing form a processing module as shown in
The ambient sensor may include at least one of the following, which are the members of the ambient sensor group consisting of: a temperature sensor, a humidity sensor, a water detection sensor, a water depth sensor, and an ice condition sensor.
The ambient report includes at least one of the following, which are the members of the ambient report component group consisting of: a temperature estimate, a humidity estimate, a water detection estimate, a water depth estimate, and an ice condition estimate.
The message may include at least one the following, a long report based upon a raw vehicular sensor waveform created from the vehicle sensor state, a report based upon at least one waveform characteristic derived from the raw vehicular sensor waveform, a timed report based upon the vehicle sensor state and the ambient report, and the ambient report. In certain embodiments, the timed report may include an average of the vehicle sensor state.
The vehicle-present may be determined by a change-in-presence based upon the waveform characteristic.
The circuit apparatus may further include an implementation as a computer accessing coupled to a memory and directed by a program system including program steps residing in the memory and/or a finite state machine.
The wireless vehicular sensor node preferably includes the circuit apparatus electrically coupled to the power source and ambient communicatively coupled to the at least one ambient sensor.
The wireless vehicular sensor nodes and wireless vehicular sensor networks built with these nodes, may be used on roadways to monitor traffic and/or survey the traffic passing over the sensors, and in parking structures to determine occupancy.
The invention includes a method of creating a road condition report from at least two wireless vehicular sensor nodes, which includes the following. Receiving a first received ambient report from a first wireless vehicular sensor node across at least one wireless physical transport and a second received ambient report from the second wireless vehicular sensor node across the wireless physical transport. Creating the road condition report based upon at least one of the estimates for at least the first received ambient report and/or the second of the received ambient report.
Each received ambient report includes an estimate of at least one of the following: a temperature estimate, a humidity estimate, a water detection estimate, a water depth estimate, and an ice condition estimate.
The first received ambient report, the second received ambient report, and the road condition report, are products of the invention's process
The invention includes apparatus implementing this method, including means for wirelessly receiving the first received ambient report from the first wireless vehicular sensor node and the second received ambient report from the second wireless vehicular sensor node across the wireless physical transport to create the road condition report based upon at least one estimate of the first received ambient report and/or the second of the received ambient report.
The means for wirelessly receiving may act as an access point in a wireless vehicular sensor network including: the first wireless vehicular sensor node and/or the second wireless vehicular sensor node.
The means for wirelessly receiving may be implemented by at least one of the following.
The invention further includes a wireless vehicular sensor network, which includes at least two wireless vehicular sensor nodes, each providing an ambient report to the apparatus implementing this method, in particular to the means for wireless receiving.
This invention relates to wireless vehicular sensor nodes used in wireless vehicular sensor networks, in particular, to the wireless vehicular sensor nodes reporting waveforms approximating the raw sensor readings due to the presence of motor vehicles and describing ambient conditions in the vicinity of the wireless vehicular sensor node.
The invention includes a circuit apparatus 800 for a wireless vehicular sensor node 500, as shown in
The circuit apparatus 800 may further include the following as shown in
The invention's circuit apparatus 800, wherein the means for using 1000, and the means for operating 140, and the means for sensing A140 form a processing module 810 as shown in
The ambient sensor A2 may include at least one of the following, which are the members of the ambient sensor group consisting of: a temperature sensor A2T, a humidity sensor A2H, a water detection sensor A2W, a water depth sensor A2WD, and an ice condition sensor A2I, as shown in
The ambient report A180 includes at least one of the following, which are the members of the ambient report component group consisting of:
The message MSG includes at least one the following, as shown in
The vehicle-present VP may be determined by a change-in-presence 126 based upon the waveform characteristic 120.
The circuit apparatus 800 may further include an implementation as a computer accessing coupled to a memory and directed by a program system including program steps residing in the memory and/or a finite state machine, as shown in various forms in
The vehicle-present VP may be determined by a change-in-presence 126 based upon at least one of the waveform characteristic 120.
The wireless vehicular sensor node 500 preferably includes the circuit apparatus 800 electrically coupled to the power source 60 and ambient communicatively coupled A12 to the at least one ambient sensor A2, as shown in
The invention includes a method of creating a road condition report RCR from at least two wireless vehicular sensor nodes, by way of example, a first wireless vehicular sensor node 500-1 and a second wireless vehicular sensor node 500-2, as shown in
Each received ambient report RA180 includes an estimate of at least one of the following: a temperature estimate RA180T, a humidity estimate RA180-H, a water detection estimate RA180D, a water depth estimate RA180WD, and an ice condition estimate RA180I, as shown in
Receiving an received ambient report, for example the first received ambient report RA180-1 may be included in at least of the following:
The first received ambient report RA180-1, the second received ambient report RA180-2, and the road condition report RCR, are products of the invention's process
The invention includes apparatus implementing this method, including means for wirelessly receiving 130 the first received ambient report RA180-1 from the first wireless vehicular sensor node 500-1 and the second received ambient report RA180-2 from the second wireless vehicular sensor node 500-2 across the wireless physical transport 1510 to create the road condition report RCR based upon at least one of the estimates for the first received ambient report and/or the second of the received ambient report, as shown in
The means for wirelessly receiving may act as an access point 1500 in a wireless vehicular sensor network 2300 including: the first wireless vehicular sensor node 500-1 and/or the second wireless vehicular sensor node 500-2, as shown in
The means for wirelessly receiving may be implemented by at least one of the following.
The invention further includes a wireless vehicular sensor network, which includes at least two wireless vehicular sensor nodes, each providing an ambient report to the apparatus implementing this method, in particular to the means for wireless receiving, as shown in
The wireless vehicular sensor node 500 may include: the circuit apparatus 800 electrically coupled to the power source 60; and the radio transceiver 20 electrically coupled to an antenna 28, as shown in
The invention includes wireless vehicular sensor nodes preferably reporting a time synchronized vehicular sensor report and/or reporting at least one ambient condition which may affect the interpretation of the time synchronized vehicular sensor reports.
The wireless vehicular sensor node 500 and the circuit apparatus 800 as sho0wn in
Power from a power source is controlled for delivery to a radio transceiver and a magnetic sensor based upon the task trigger and the task identifier. The radio transceiver, the magnetic sensor and the ambient sensor(s) are operated based upon the task identifier, when the task trigger is active. Operating the magnetic sensor includes constructing the time synchronized vehicular sensor report when the task trigger indicates capturing the vehicular sensor state from the magnetic sensor. Operating the radio transceiver includes transmitting the time synchronized vehicular sensor report based upon the detection of the presence of a vehicle passing near the wireless vehicular sensor node when the task identifier indicates transmission may be performed.
The means for controlling 310 receives and uses the task trigger 38 and the task identifier 34 to control the following: a first power 312-1 to a magnetic sensor 2, a fourth power 312-4 to a radio transceiver 20, and a sixth power 312-6 to at least one ambient sensor A2. the means for controlling also controls at least one of the following: a second power 312-2 to a means for using 1000 the magnetic sensor, a third power 312-3 to a second means for operating 140 the radio transceiver, a fifth power 312-5 to a means for sensing A140 the at least one ambient sensor.
The means for operating the node 320 receives and uses the task trigger 38 and the task identifier 34 to create a use-magnetic-sensor trigger 322-1 and a use-ambient-sensor trigger 322-2. The means for operating the node may further create at least one of the following, which are referred to elsewhere in this document as the members of the optional trigger group: a send-short-report trigger 322-3, a send-waveform-report trigger 322-4, a receive-synchronization-message trigger 322-5, and a send-timed-report trigger 322-6.
The vehicle-present trigger 324 may be based upon the raw vehicular sensor waveform 110 and/or the vehicle sensor state 114. The vehicle-present trigger is used by the means for operating 140 the radio transceiver 20 to send the message MSG.
The time synchronization will be discussed in terms of the operations of the means for wirelessly receiving using an example implementation shown in
There are at least two basic approaches to creating time synchronization at the system level. The first approach time synchronizes the first raw vehicular sensor waveform observed at the first wireless vehicular sensor node with the second raw vehicular sensor waveform observed at the second wireless vehicular sensor node. In the second approach, the time synchronization is performed by the means for wirelessly receiving using the transmit times of the reports and from the wireless vehicular sensor nodes, along with their reception time at the means for wirelessly receiving, as shown in
The first approach may further include all the relevant wireless vehicular sensor nodes wirelessly receiving a time synchronization message. The first wireless vehicular sensor node and the second wireless vehicular sensor node both receive the time synchronization message as shown in
Multiple wireless vehicular sensor nodes are used to wirelessly receive multiple time-synchronized vehicular waveform reports, creating a time synchronized system report. By way of example, the invention uses a first wireless vehicular sensor node and a second wireless vehicular sensor node to wirelessly receive a first vehicular waveform report from the first wireless vehicular sensor node time-synchronized with a second vehicular waveform report from the second wireless vehicular sensor node as shown in
Time synchronization supports a more rigorous analysis of the vehicular waveform reports, due to essentially the aligning the times of successive samples of the reports. Consider the example of the vehicle of
The use of time synchronization can be further seen in
The invention includes a node program system implementing the method residing in a memory accessible coupling to at least one computer, comprising the program steps creating the time synchronized system report and/or creating the time synchronized vehicular report. The memory may include at least one instance of one or more of the following: a magnetic disk, an optical disk, a non-volatile memory component, a volatile memory component, and a bar coded medium.
The wireless vehicular sensor node 500 may include the following. Means for maintaining 300 a clock count 36, a task trigger 38, and a task identifier 34. Means for controlling a power source, may preferably distribute electrical power to the means for using 1000 and the means for operating 140, based upon the task trigger and the task identifier. The means for using may be provided operating power, when the magnetic sensor 2 is used to create the vehicular sensor waveform and/or to create its waveform characteristic 120 and/or its second waveform characteristic 120-2. These may then be preferably used to generate the report 180. The means for operating 140 may be provided operating power, when the report is to be sent to the access point 1500 across at least one wireless physical transport 1510, either directly, or via the intermediate node 580.
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 radio transceiver 20 and means for using 1000 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.
The wireless vehicular sensor node 500 of
Often, the vehicle sensor state 104, when collected over time T200, 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 the vehicle sensor state 104, shown in
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 magnetic sensor 2.
The up-threshold 184 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 magnetic 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 2300. Often these units may be preferred to be in terms of 1/1024 of a second, or roughly 1 ms.
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 304 of
The operation 312 of
The operation 236 of
The wireless vehicular sensor node 500 includes a magnetic sensor 2, preferably having a primary sensing axis 4 for sensing the presence of a vehicle 6, as shown in
By way of example, the magnetic sensor 2 may include a two axis magneto-resistive sensor. A two axis magneto-resistive sensor may be used to create the vehicle sensor state as follows. The X-axis may be used to determine motion in the primary sensor axis 4. The Z-axis may be used to determine the presence or absence of a vehicle 6.
Another example, the magnetic sensor 2 may further preferably include a three axis magneto-resistive sensor. A three axis magneto-resistive sensor may be used to create the vehicle sensor state as follows. The X-axis may also be used to determine motion in a primary sensor axis 4. The Y-axis and Z-axis may be used to determine the presence or absence of a vehicle 6. In certain embodiments, the Euclidean distance in the Y-Z plane is compared to a threshold value, if greater, then the vehicle is present, otherwise, absent. The vehicular sensor may preferably include one of the magneto-resistive sensors manufactured by Honeywell.
Transmitting the report 180 and/or the long report 190 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 reports may be spread across a frequency band of the wireless physical transport. More particularly, the transmitting of reports may include a chirp and/or a spread spectrum burst across the frequency band.
The transmitter 22 of
The report 180 and/or the long report 190 may further identify the wireless vehicular sensor node 500 originating the report. Transmitting the report may initiate a response across the wireless physical transport, preferably from an access point. The response may be an acknowledgement 182 of receiving the report.
The invention includes using multiple of these wireless vehicular sensor nodes to wirelessly receive multiple time-synchronized vehicular waveform reports from the wireless vehicular sensor nodes. By way of example, the invention uses a first wireless vehicular sensor node 500-1 and a second wireless vehicular sensor node 500-2 to wirelessly receive 130 a first vehicular waveform report 132-1 from the first wireless vehicular sensor node time-synchronized 166 with a second vehicular waveform report 132-2 from the second wireless vehicular sensor node to create the time synchronized system report 1080 as shown in
Time synchronization supports a more rigorous analysis of the vehicular waveform reports, due to essentially the aligning the times of successive samples of the reports. Consider the example of the vehicle 6 of
Because of these delays in receiving the reports, there may be no coherent system picture that can be developed. Reports for the same vehicle may be so scattered about in time that some reports are deleted before others even arrive at the means for wirelessly receiving 130. The use of time synchronization can be further seen in
The method of time synchronization will be discussed in terms of the operations of the means for wirelessly receiving 130 using an example implementation shown in
There are at least two basic approaches to creating time synchronization at the system level. The first approach time synchronizes the first raw vehicular sensor waveform 110-1 observed at the first wireless vehicular sensor node 500-1 with the second raw vehicular sensor waveform 110-2 observed at the second wireless vehicular sensor node 500-2. In the second approach, the time synchronization is performed by the means for wirelessly receiving 130 using the transmit times of the reports 132-1 and 132-2 from the wireless vehicular sensor nodes, along with their reception time 1060 at the means for wirelessly receiving, as shown in
The first approach may further include all the relevant wireless vehicular sensor nodes wirelessly receiving a time synchronization message. The first wireless vehicular sensor node 500-1 and the second wireless vehicular sensor node 500-2 both receive the time synchronization message 160 as shown in
The access point may preferably send the time synchronization message. By way of example, the access point 1500 may preferably send 168 the time synchronization message to both the first wireless vehicular sensor node 500-1 and the second wireless vehicular sensor node 500-2, as shown in
The wireless vehicular sensor network 2300 may support a version of the IS-95 communications standard 178, or a version of the IEEE 802.11 communications standard 179. The network may support other spread spectrum and/or orthogonal frequency division multiplexing schemes, including but not limited to, Code Division Multiple Access 177, frequency hopping and time hopping scheme.
The wireless vehicular sensor nodes preferably send a long report, including a first event time and event samples for successive time steps. The long report 190 is preferably generated within the wireless vehicular sensor node 500, as shown in
The long report 190 may further preferably include a raw waveform event entry 192 including the first event time, a raw sample X 196-X, a raw sample Y 196-Y, and a raw sample Z 196-Z. The first event time may include a frame-count 156 and a time-stamp 158, which will be further discussed regarding the use of the vehicular sensor node for traffic monitoring.
The event samples of successive time steps may be reported with an instance of a differential waveform event entry 194, each of which includes a differential sample of X 198-X, a differential sample of Y 198-Y, and a differential sample of Z 198-Z, as shown in
The long report 190 preferably includes the raw waveform event entry 192 and N-1 instances of the differential waveform event entry 194. N may be preferred to be a power of two, and may further be preferred to be sixteen. The time step is preferably chosen to support at least 128 samples per second, further preferably supporting 256 samples per second. Each of the raw samples, X, Y, and Z, may preferably be represented by an integer or fixed point number of at least 8 bits, preferably, 12 bits, and further preferably 16 bits. The long report may further be compressed at the wireless vehicular sensor node using code compression techniques such as Huffman coding. The instances of the differential waveform event entry shown in
In the second approach to time synchronization, each long report 190 may include the transmit time 199 observed at the node when the long report was sent.
Each vehicular waveform report approximates a raw vehicular sensor waveform observed by a magnetic sensor at the vehicular sensor node based upon the presence of a vehicle. The first vehicular waveform report 132-1 approximates the first raw vehicular sensor waveform 110-1 observed by a first magnetic sensor 2-1 at the first wireless vehicular sensor node 500-1 based upon the presence of a first vehicle 6-1. The second vehicular waveform report 132-2 approximates the second raw vehicular sensor waveform 110-2 observed by a second magnetic sensor 2-2 at the second wireless vehicular sensor node 500-2 based upon the presence of a second vehicle 6-2.
Continuing the discussion of the second approach to time synchronization, consider again
The time synchronization list 1070 preferably includes the difference between the reception time and the transmit time as the time offset for the wireless vehicular sensor node. By way of example, the time synchronization list includes the first time offset 1072-1 for the first wireless vehicular sensor node 500-1 and the second time offset 1072-2 for the second wireless vehicular sensor node 500-2, both of which are calculated in this fashion.
Whether or not the long report 190 from the first wireless vehicular sensor node 500-1 is time-interleaved 134 with the long report from the second wireless vehicular sensor node 500-2, the long report is used to build the time synchronized system report 1080 by providing a reported sample from either the raw waveform event entry 192 or an instance of the differential waveform event entry 194 as shown in
The time synchronized system report 1080 preferably includes multiple instances of the system event entry 1082, which includes the first sensor sample 1084-1 from a long report 190 received from the first wireless vehicular sensor node 500-1 and the second sensor sample 1084-2 from another long report received from the second wireless vehicular sensor node 500-2. The first sensor sample and the second sensor sample are report time synchronized 166 to a system time 1086, which may be either explicitly or implicitly part of the system event entry. The system time is derived by examining the long report 190 for the transmit time 199 and the time-stamp 158, and calculating the system time also based upon the first time offset 1072-1 from the time synchronization list 1070. Typically, the raw waveform event entry 192 is at the time-stamp, whereas each subsequent differential waveform event entry 194 is at a time-increment from its predecessor.
As used herein, each of the invention's wireless vehicular sensor node operates a magnetic sensor. The first wireless vehicular sensor node first operates 104-1 the first magnetic sensor. And the second wireless vehicular sensor node second operates 104-2 the second magnetic sensor. At least one, and often preferably, all the wireless vehicular sensor nodes may include their magnetic sensors. By way of example,
The first vehicular waveform report 132-1 and the second vehicular waveform report 132-2 are products of the process of wirelessly receiving first vehicular waveform report time-interleaved with the second vehicular waveform report.
The invention includes apparatus supporting the above outlined process, including means for wirelessly receiving 130 the first vehicular waveform report 132-1 from the first wireless vehicular sensor node 500-1 time-interleaved with the second vehicular waveform report 132-2 from the second wireless vehicular sensor node 500-2.
The means for wirelessly receiving 130 may first wirelessly communicate 100-1 with the first wireless vehicular sensor node 500-1. The means for wirelessly receiving may also second wirelessly communicate 100-2 with the second wireless vehicular sensor node 500-2. Note that these wireless communications may or may not use the same physical transports and/or communications protocols. These wireless communications may be encrypted, and the communications with one wireless vehicular sensor node may or may not be decipherable by the other wireless vehicular sensor node.
The time-interleaved reception 134 is shown through a series of snapshots of the means for wirelessly receiving 130 of
An example of an embodiment in which the first vehicle 6-1 may be the same as the second vehicle 6-2 is shown in
Alternatively, the first vehicle 6-1 may be distinct from the second vehicle 6-2 as shown by the example of
A wireless vehicular sensor network may include the first and/or the second wireless vehicular sensor node. Both may preferably be included in the same wireless vehicular sensor network.
A wireless vehicular sensor network 2300 may include at least one of the first wireless vehicular sensor node 500-1 and the second wireless vehicular sensor node 500-2. By way of example, the wireless vehicular sensor network may include exactly one wireless vehicular sensor node used for receiving the vehicular waveform report, as shown in
The wireless vehicular sensor network may further include an access point communicating with both the first wireless vehicular sensor node and the second wireless vehicular sensor node. The wireless vehicular sensor network may further include an access point 1500 communicating with both the first wireless vehicular sensor node and the second wireless vehicular sensor node as shown in
Wirelessly receiving the first, time-synchronized, and often time-interleaved with the second, vehicular waveform report may further include wirelessly receiving via the access point. This may include wirelessly receiving via the access point 1500 the first vehicular waveform report 132-1 from the first wireless vehicular sensor node 500-1, time-synchronized, and often time-interleaved with the second vehicular waveform report 132-2 from the second wireless vehicular sensor node 500-2.
By way of example, the means for wirelessly receiving the first, time synchronized 166 and time-interleaved 134 with the second, vehicular waveform report may include the means for wirelessly receiving 130 via 136 the access point 1500 the first vehicular waveform report 132-1 from the first wireless vehicular sensor node 500-1 time-interleaved with the second vehicular waveform report 132-2 from the second wireless vehicular sensor node 500-2, as in
Another example, the means for wirelessly receiving 130 the first, time synchronized 166 and time-interleaved 134 with the second, vehicular waveform report may further include an access point 1500 for wirelessly communicating with one but not both wireless vehicular sensor nodes, as shown in
Another example, the means for wirelessly receiving 130 the first, time synchronized 166 and time-interleaved 134 with the second, vehicular waveform report may further include using two access points, for two wireless vehicular sensor networks to wirelessly communication with the wireless vehicular sensor nodes, as shown in
The means for wirelessly receiving may include at least one instance of at least one of a computer, a finite state machine, and an inferential engine. The instance at least partly implements the method by wirelessly communicating with at least one of the wireless vehicular sensor nodes. The instance may communicate with the wireless vehicular sensor nodes via an access point.
The access point may include the means for wirelessly receiving. The access point may be a base station communicating with at least one of the first wireless vehicular sensor node and the second wireless vehicular sensor node.
By way of example, the means for wirelessly receiving 130 may include at least one instance of a computer 12 at least partly implementing the method as shown in
The computer 12 is preferably accessibly coupled 16 with a memory 14 including at least one program step included in a program system 600 directing the computer in implementing the method.
The computer 12 communicating with the first and second wireless vehicular sensor nodes may further include the computer communicating via the access point 1500 with the first wireless vehicular sensor node 500-1 to wirelessly receive 102-1 the first vehicular waveform report 132-1, and with the second wireless vehicular sensor node 500-2 to second wirelessly receive 102-2 the second vehicular waveform report 132-2.
Another example, the means for wirelessly receiving 130 may include at least one instance of a finite state machine 26 at least partly implementing the method as shown in
The finite state machine 26 communicating with the wireless vehicular sensor nodes may further include the finite state machine communicating via the access point 1500 with the first wireless vehicular sensor node 500-1 to wirelessly receive 102-1 the first vehicular waveform report 132-1, and with the second wireless vehicular sensor node 500-2 to second wirelessly receive 102-2 the second vehicular waveform report 132-2.
Another example, the means for wirelessly receiving 130 may include at least one instance of an inferential engine 24 at least partly implementing the method as shown in
The inferential engine 24 communicating with the wireless vehicular sensor nodes may further include the inferential engine communicating via the access point 1500 with the first wireless vehicular sensor node 500-1 to wirelessly receive 102-1 the first vehicular waveform report 132-1, and with the second wireless vehicular sensor node 500-2 to second wirelessly receive 102-2 the second vehicular waveform report 132-2.
The receiver 18 shown in
The invention may use more than two wireless vehicular sensor nodes, and include any combination of time-interleaved reception of vehicular waveform reports from wireless vehicular sensor nodes.
By way of example, consider
The following are examples of combinations of time-interleaved reception of the vehicular waveform reports.
Wirelessly receiving the time-interleaved vehicular waveform reports, may further include wirelessly receiving the time-interleaved vehicular waveform reports, when the observed vehicles are each within a distance of the corresponding magnetic sensors.
For example, wirelessly receiving the first time-interleaved with the second vehicular waveform report, may further include wirelessly receiving 130 the first vehicular waveform report 132-1 from the first wireless vehicular sensor node 500-1 time-interleaved 134 with the second vehicular waveform report 132-2 from the second wireless vehicular sensor node 500-2, when the first vehicle 6-1 is within a first distance 108-1 of the first magnetic sensor 2-1, and when the second vehicle 6-2 is within a second distance 108-2 of the second magnetic sensor 2-2, as shown in
The first distance 108-1 may be essentially the same as the second distance 108-2. Alternatively, the first distance may be distinct from the second distance. Both the first distance and the second distance may be at most three meters. Further preferred, both may be at most two meters. Further, both may be at most one meter.
Wirelessly receiving the time-interleaved vehicular waveform reports, may further include wirelessly receiving the time-interleaved vehicular waveform reports, when the observed vehicles are each within a distance of the corresponding magnetic sensors. The node may already determine when a vehicle is close enough, by determining a rising edge and/or a falling edge of a vehicular sensor waveform, which is the result of the vehicle moving near that node. During normal traffic monitoring operations, the node preferably transmits a report of only the waveform characteristics, which may include the rising edge and the falling edge. It may be further preferred that the node report the raw vehicular sensor waveform from a predetermined time before the rising edge until a second predetermined time after the falling edge.
The invention includes the ability to control turning on and off the vehicular waveform report 132-1 and 132-2 from the wireless vehicular sensor nodes 100-1 and 100-2 based upon whether a vehicle 6 is present or not present. These reports preferably start shortly before the rising edge 108 and continue until shortly after the falling edge 110. By way of example, the operation of a wireless vehicular sensor node 500 may be discussed in terms of a program system 200, as shown in
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, 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.
Consider the following example of a wireless vehicular sensor network 2300 including an access point 1500 and multiple wireless vehicular sensor nodes as shown in
Preferably, a wireless vehicular sensor node 500 includes a means for maintaining 300 a clock count 36, task trigger 38, and task identifier 34, as shown in
By way of example, the time division multiple access protocol may synchronize the wireless vehicular sensor network 2300 to operate based upon a frame with a frame time period. The frame time period may preferably approximate at least one second. The time division multiple access protocol may operate in terms of time slots with a time slot period. The time slot period may be preferred to be a fraction of the frame time period. The fraction may preferably be a power of two. The power of two may preferably be one over 1K, which refers to the number 1,024. The time slot period then approximates a millisecond. The wireless vehicular sensor network may further organize the report 180 in terms of a meta-frame, which may preferably have a meta-frame time period as a multiple of the frame time period. The meta-frame time period may preferably be thirty times the frame time period, representing a half of a minute.
The report 180 may preferably include a waveform event list 150 for the waveform characteristics observed by the wireless vehicular sensor node 500 during the current and/or most recent meta-frame. A waveform characteristic 120 may be represented in the waveform event list by a waveform event entry 152 including the following. A presence-flag 154 indicating the presence or absence of the vehicle 6. A frame-count 156 indicating the frame in the meta-frame, and a time-stamp 158 indicating the time slot within that frame in which the waveform characteristic occurred.
The waveform event list 150 may include a fixed number N of instances of the waveform event entry 152, to minimize computing and power consumption at the wireless vehicular sensor node 500. The fixed number N may be a power of two, such as 32 or 20.
The presence-flag 154 may represent a vehicle 6 being present with the binary value ‘1’, and the absence of the vehicle with a ‘0’. Alternatively, ‘0’ may represent the presence of the vehicle. And its absence by ‘1’.
The frame-count 156 may be represented in a five bit field. The time-stamp 158 may be represented in a ten bit field.
The waveform event entry may be considered as a fixed point number, preferably 16 bits. When the waveform event entry has one of the values of 0x7FFF or 0xFFFF, it represents a non-event, no additional waveform characteristic 120 has been determined by the wireless vehicular sensor node.
The access point 1500 may be a base station 1500 communicating with at least one of the first wireless vehicular sensor node 500-1 and the second wireless vehicular sensor node 500-1.
Returning to discuss organization of the traffic monitoring activities and their relationship with this invention,
The discussion of the operation of the means for wirelessly receiving 130 the time synchronized reports will proceed based upon the second program system 1200 as shown
The operation of the means for wirelessly receiving 130 may be implemented by the second program system 1200 of
During the initialization of the system using the means for wirelessly receiving 130, the time synchronization list 1070 is preferably setup to include a time offset for each of the wireless vehicular sensor nodes which may send the long report 190. By way of example, the time synchronization list of
Operation 1202 of
Operation 1204 of
Operation 1220 of
Operation 1222 of
The preceding embodiments provide examples of the invention and are not meant to constrain the scope of the following claims.
This application is a continuation in part of patent application Ser. No. 11/315,025, filed Dec. 20, 2005, and patent application Ser. No. 11/339,089 filed Jan. 24, 2006, and claims priority to Provisional Patent Application 60/695,742, filed on Jun. 29, 2005, and is also a continuation in part of patent application Ser. No. 11/062,130, filed Feb. 19, 2005, 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. 22, 2004, all of which are incorporated herein by reference.
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| Number | Date | Country | |
|---|---|---|---|
| 20060202863 A1 | Sep 2006 | US |
| Number | Date | Country | |
|---|---|---|---|
| 60695742 | Jun 2005 | US | |
| 60630366 | Nov 2004 | US | |
| 60549260 | Mar 2004 | US |
| Number | Date | Country | |
|---|---|---|---|
| Parent | 11339089 | Jan 2006 | US |
| Child | 11422074 | US | |
| Parent | 11315025 | Dec 2005 | US |
| Child | 11339089 | US | |
| Parent | 11062130 | Feb 2005 | US |
| Child | 11315025 | US |
