WO2007149169A2

WO2007149169A2 - Human collision avoidance system and method

Info

Publication number: WO2007149169A2
Application number: PCT/US2007/011783
Authority: WO
Inventors: Alex Kalpaxis
Original assignee: 24Eight Llc
Priority date: 2006-05-17
Filing date: 2007-05-17
Publication date: 2007-12-27
Also published as: WO2007149169A3; WO2007149169A9

Abstract

ABSTRACT The disclosed method for wireless real-time human collision avoidance using link energy power factor to determine a distance of a wearer to an obstacle includes the steps of wearing, on a person, a wireless pendant. The wireless pendant (130) sends and monitors mesh-type network packet data to and from complementary wireless component tags (110A-C) attached to obstacles. The collected wireless component tag RF packet power factor is signal averaged and temporally smoothed using dynamically sized moving average convolution filters and storing the results at the wireless pendant. Using the signal averaging and temporally smoothing results, a Link Energy LE(x,y,z,t) result is created. The wireless pendant correlates the Link Energy LE(x,y,z,t) results with a near-field or far-field RF energy-to-range/distance profile table to derive various coefficients and calculates the current distance for the wireless pendant to the wireless component tags. A wireless pendant data collector server (120) can be provided.

Description

HUMAN COLLISION AVOIDANCE SYSTEM AND METHOD

Background

This application relates to methods and apparatuses for a wireless real-time human collision avoidance system using the wireless channel's link energy, which is a factor in determining the distance of a person to an obstruction. More specifically, this application relates to methods and apparatuses for determining distance to a potential hazardous obstruction and generating an alarm event when a designated distance is crossed.

Summary

It is desirable to provide a method and apparatus for wirelessly detecting a potential human collision with an obstruction via a low-powered wireless pendant attached to a helmet or hat or attached to a key chain or worn on a belt by a person. The wireless pendant contains a Micro-controller Processor Unit (MPU), which incorporates a wireless spread-spectrum sensor network transceiver, to communicate with a similar wireless pendant called a component tag unit, which is attached to the obstructions or obstacles. The designated distance is programmable in the apparatus, and can be viewed as a guarded perimeter around the obstruction. The apparatus includes two parts: a wireless component that Tags (is attached to or otherwise marks) the obstruction and one or more wireless components that persons will carry as wireless devices attached to a helmet or hat or key chain or worn on a belt. The methods and apparatus monitor and correlate the distance between the wireless component marking an obstruction and any number of wireless devices attached to persons at a pre-determined minimum rate, where a default can be ten times a second for instance, and which wireless components are within the wireless spread-spectrum link range, which is approximately 30 meters. Potential collision situations that the disclosed system will help avoid are low height entrance doorways (such as in basements), low-hung beams, temporary construction obstructions and/or obstacles, potential collision with obstruction/obstacles in low and/or no light situations or other poor or non-visability situations. An option is a wireless pendant data collection apparatus that connects to a Personal Computer (PC) and wirelessly collects the time stamped collision avoidance alarms from the wireless pendants worn or carried by persons. This feature will provide heuristic traffic analysis around the wireless component Tagged obstacles. The alarms can be audio, visual or tactile, or mixtures of two or more types of indicators. The wireless spread-spectrum link energy is used to determine the distance between the person and the obstacle. The link energy is determined by LE(x,y,z,t) = ∑jp(x,y,z)*dt, where P(x,y,z) is the Radio Frequency (RF) power factor of a spread- spectrum sensor network link packet received at the point defined by the x_μ,y_μ>z coordinates (as defined in LE(x,y,z,t)), which is the position of the person wearing the wireless pendant at a point in time defined by t (as defined in LE(x,y.z,t)). The link energy is preferably a result of signal averaging using moving average convolution filters to remove noise and interference. An exemplary signal averaging session is based on a dynamic time-based window which is a function of the desired distance (called the guard perimeter). The guard perimeter is the distance from the obstacle with the attached wireless component tag to the wireless pendant worn by the person. When the guard perimeter is breached by the person wearing the pendant, an alarm will be generated. The MPU will perform a minimum number of current distance calculations per second, and compare the current distance of the wireless pendant to the guard perimeter distance for the component tag. The MPU will generate an alarm as soon as the current distance of the wireless pendant is equal to or less than the guard perimeter distance. The MPU will adjust its distance algorithm based on the guard perimeter size.

As the person wearing the wireless pendant comes within the wireless spread-spectrum link energy range limit (about 30 meters, for example) of the wireless component tag on the obstacle, a communication link is established between the wireless pendant and the wireless component tag. The MPU on the wireless pendant measures the link energy of the communication link using power level factors received from an RF transceiver, the power levels are signal averaged and integrated over a dynamic time window. As the person wearing the wireless pendant comes within the guard perimeter, that is, the person is at or crosses the guard perimeter, an alarm is generated by the wireless pendant. The MPU in the wireless pendant measures the current distance from the wireless component tag to itself and compares this to the guard perimeter a minimum number of times per second, preferably at least 10 times per second in an exemplary embodiment of the invention. Therefore, it is an aspect of an exemplary embodiment to provide a method and apparatus for wireless real-time human collision avoidance using wireless spread-spectrum communications channel link energy calculations.

It is a further aspect of an exemplary embodiment to provide a method and apparatus for wireless real-time human collision avoidance using wireless spread- spectrum pendants on persons and a wireless spread-spectrum wireless component tag on an obstacle.

It is a further aspect of an exemplary embodiment to provide a method and apparatus for wireless real-time human collision avoidance using programmable guard perimeters between wireless spread-spectrum pendants on persons and a wireless spread-spectrum wireless component tag on an obstacle.

It is a further aspect of an exemplary embodiment to provide a method and apparatus for the wireless real-time human collision avoidance system to generate an alarm when the programmable guard perimeters between wireless spread-spectrum pendants on a person and a wireless spread-spectrum wireless component tag on an obstacle are crossed.

It is a further aspect of an exemplary embodiment to provide a method and apparatus for the wireless real-time human collision avoidance system to generate alarms when the programmable guard perimeters between wireless spread-spectrum pendants on persons and wireless spread-spectrum wireless component tags on multiple obstacles are crossed.

It is a further aspect of an exemplary embodiment to provide a method and apparatus for the wireless real-time human collision avoidance system to generate reports via a wireless pendant data collection apparatus that connects to a Personal Computer (PC) and wirelessly collects the time stamped collision avoidance alarms from the wireless pendants worn or carried by persons in an area, which provides heuristic traffic analysis around tagged obstacles located in this area. Another aspect is to provide a method and apparatus for the wireless realtime human collision avoidance system to be noise and interference immune by utilizing wireless spread-spectrum communication channels instead of current system that utilize optical, acoustic, or other wireless techniques. By using a wireless spread-spectrum communication channel, the wireless real-time human collision avoidance system has experienced approximately 250% reduction in error rate as compared to traditional wireless techniques, such as Bluetooth or other similar wireless techniques. The windowed moving average convolution filtering algorithms methods further enhances signal smoothing and further improves the signal-to-noise ratios in the disclosed system.

A further aspect of an exemplary embodiment is to provide a method and apparatus for the wireless real-time human collision avoidance system to have multi- path reliability by utilizing the wireless spread-spectrum communication channel that implements the IEEE 802.15.4 (i.e., ZigBee) sensor network standard, which allows for multi-path redundancy in a mesh-network type configuration. By utilizing this type of wireless spread-spectrum communication channel, the wireless real-time human collision avoidance system will continue to perform its function in the event of wireless pendant or component tag failures in a large cluster of wireless pendants and wireless component tags. The disclosed method for wireless real-time human collision avoidance using link energy power factor to determine a distance of a wearer to an obstacle includes the steps of wearing, on a person, a wireless pendant. The wireless pendant sends and monitors mesh-type network packet data to and from complementary wireless component tags attached to obstacles. The collected wireless component tag RF packet power factor is signal averaged and temporally smoothed using dynamically sized moving average convolution filters and storing the results at the wireless pendant. Using the signal averaging and temporally smoothing results, a Link Energy LE(x,y,z,t) result is created, which is ∑/P(x,y_sz)*dt, where P(x,y,z) is the Radio Frequency (RF) power factor of a spread-spectrum sensor network link packet received at the point defined by the x,y,z coordinates as defined in LE(x,y,z,t). The wireless pendant correlates the Link Energy LE(x,y,z,t) results with a near-field or far-field RF energy-to-range/distance profile table to derive various coefficients and calculates the current distance for the wireless pendant to the wireless component tags attached obstructions. It also has a wireless pendant data collector server.

Description of the Drawings

The above and other aspects of the exemplary embodiments are achieved by methods and apparatuses herein described. The reader should understand that the drawings depict present preferred and best mode embodiments of the invention, and are not to be considered as limiting in scope. Exemplary embodiments will be described with reference to the following drawing figures.

Figure 1 is a process flow chart showing the information flow and processing steps of the wireless collision avoidance data collection method in accordance with the present disclosure. Figure 2 illustrates a simplified high-level block diagram of the wireless pendant and the wireless component tag.

Figure 3 is a flow chart showing non-interrupt routines run on the wireless pendant's MPU.

Figure 4 illustrates a block diagram of the interrupt handlers run on the wireless pendant's MPU.

Figure 5 is a sequence diagram of communication link protocol between the wireless pendant and the wireless component tag attached to the obstacle.

Figure 6 illustrates the internal subsystems of the Wireless Pendant Data Collection server. Figure 7 illustrates the block diagram of an eleventh-order filter.

Figure 8 illustrates the block diagram of an n^th-order filter.

Detailed Description

Reference will now be made in detail to the preferred embodiment, examples of which are illustrated in the accompanying drawings. Figure 1 is a block diagram representation of an exemplary system according to an embodiment of the present disclosure. The system 100 comprises at least one wireless pendant 130, at least one wireless pendant data collection server 120 and at least one wireless component Tags 110.

The wireless pendant device 130 is preferably worn by a person to provide an alarm when impending collisions are about to occur with obstacles having wireless component tags 11 OA-C attached to them. The wireless pendant 130 and the wireless component tag 1 lOA-C exchange data and create a pre-programmed guard perimeter as soon as they are within about 30 meters from each other, or when manually controlled to do so by a user. The wireless pendant 130 preferably continually checks its current position with that of a wireless component tag 11OA, for example, that it had previously established a connection with to detect the breaching of the guard perimeter. Preferably, all wireless pendants 130 and wireless component tags 1 lOA-C have unique IEEE 64-bit Media Access Control (MAC) addresses, or some other means of identification. This allows for the wireless pendant 130 worn by a person to track multiple obstacles having wireless component tags 1 lOA-C attached to the obstacles.

Figure 2 shows a detailed view of the system according to an exemplary embodiment. The system 200 comprises plural wireless component tag 21 OA-N, a wireless pendant data collection server 220, and a wireless pendant 230. The wireless pendant device 233 can be any type of wireless device that is suitable to be carried on, by a person or machine or other movable object, or attached thereto. However, for sake of the described examples, the wireless device 233 will be referred to throughout the specification as a wireless pendant. The wireless pendant device comprises an MPU 233, a serial peripheral interface (SPI) 235, an RF transceiver 237 and an actuation device 239 (e.g., a button). The wireless pendant data collection server 220 comprises an RF transceiver 223, an MPU 225 and an personal computer interface (PCI) 227. The wireless component tags comprise an MPU 213, an SPI 215, and an RF transceiver 217.

The wireless pendant MPU 233 preferably creates a table in memory that contains all of the component tags 21 OA-N that the wireless pendant 233 has encountered since its last reset. This table is updated in real-time by the wireless pendant MPU 233. Each component tag 21 OA-N transmits an RF packet. The RF packets that traverse the wireless communications links are all uniquely identifiable and have associated with them a RF power factor. Based on the RF packet's power factor, the wireless pendant MPU 233 makes a determination on whether this is a near-field or far-field RF packet transmission with respect to the wireless component tag 210A-N from which this RF packet was transmitted. Once the field condition has been determined, the RF packet power factor signal is averaged via a variable sampling window with any already accumulated and processed RF power factor signals for this particular wireless component tag, for example, 210A. At the end of the time based sampling window, the RF power factor signal is signal averaged, smoothed and integrated with respect to time and is modulated by the inverse square law with distance to produce the Link Energy LE(x,y,z,t).

This Link Energy LE(x,y,z,t) result is correlated by the wireless pendant MPU 233 with a near-field or far-field RF energy to distance profile table to derive various coefficients that the MPU 233 uses to calculate the current distance for this wireless pendant 230 to the particular obstacle to which the wireless component tag 210 is attached.

The person wearing the wireless pendant 230 can manually create the desired guard perimeter to the tagged obstacles. The desired guard perimeters are created by the person wearing the wireless pendant 230 standing at the desired distance from the tagged obstacle for which the guard perimeter is to be created. A actuation device 239, such as a button, is preferably provided on the wireless pendant 230, which may be briefly actuated to register the guard perimeter of this particular tagged obstacle. Up to 2048 guard perimeters to tagged obstacles can be setup in the wireless pendant, all of which will be monitored in real-time as the person wearing the wireless pendant navigates and traverses the area containing the registered tagged obstacles.

The preferred wireless network is preferably defined by the IEEE 802.15.4 specification and is commercially known as ZigBee. Of course, other specifications can be used. This network allows for multi-path redundancy in a mesh-network type configuration. In addition, the link energy of the transmissions between nodes is available as part of the protocol of the network, and is useful for determining distance. Any network protocol providing similar capabilities may be used. This network technology provides for the best protection against failure. By placing the wireless IEEE 802.15.4 mesh network receivers and transmitters in groups, the mesh network that results provides redundant paths to ensure alternate data path routes exist and that there is no single point of failure should a node fail. Wireless IEEE 802.15.4 routers having extra specialized software running in the node are used to extend the range of the network by acting as relays for nodes that are to far apart to communicate directly. Wireless pendants 230 worn by multiple persons may also serve as relay nodes. An exemplary embodiment uses this wireless technology standard for the communication required between the wireless pendant 230 and the wireless pendant data collection server 220.

The wireless data communications implement a 128-bit Advanced Encryption Standard (AES) algorithm for encryption and incorporates all the strong security contained within IEEE 802.15.4 mesh-network standard. The security services implemented include methods for key establishment and transport, device management and frame protection. The exemplary embodiments leverage the security concept of a Trust Center. The Trust Center allows the node devices into the network, distribute keys and enable end-to-end security between the wireless pendant 230 and wireless pendant data collection server devices 220.

Wireless Pendant Hardware

Continuing to refer to Figure 2, the wireless pendant 230 preferably uses a IEEE 802.15.4 compliant 2.4 GHz Industrial, Scientific, and Medical (ISM) band Radio Frequency (RF) transceiver. It contains a complete 802.15.4 Physical layer (PHY) modem designed for the IEEE 802.15.4 wireless standard which supports peer-to-peer, star, and mesh networking. It is preferably combined with an MPU 511 to create the required wireless RF data link and network. The IEEE 802.15.4 transceiver supports 250 kbps O-QPSK data in 5.0 MHz channels and full spread- spectrum encode and decode.

All control, reading of status, writing of data, and reading of data is done through the RF transceiver interface port. The wireless pendant MPU 233 accesses the wireless pendant RF transceiver 237 through interface transactions in which multiple bursts of byte-long data are transmitted on the interface bus. Each transaction is preferably three or more bursts long depending on the transaction type, although shorter bursts can be used. Transactions are always read accesses or write accesses to register addresses. The associated data for any single register access is preferably 16 bits in length. Receive mode is a state where the wireless pendant RP transceiver 237 is waiting for an incoming data frame. The packet receive mode allows the wireless pendant RF transceiver 237 to preferably receive a whole packet without intervention from the device MPU 233. The entire packet payload is preferably stored in RX Packet RAM, and the micro controller fetches the data after determining the bit length and validity of the RX packet.

The device RF transceiver 237 waits for a preamble followed by a Start of Frame Delimiter. From there, the Frame Length Indicator is used to determine length of the frame and calculate the Cycle Redundancy Check (CRC) sequence. After a frame is received, the wireless pendant MPU 233 determines the validity of the packet. Due to noise, it is possible for an invalid packet to be reported with either of the following conditions: A valid CRC and a frame length (0, 1 , or 2) and/or invalid CRC/invalid frame length.

The wireless pendant MPU 233 software application determines if the packet CRC is valid, and that the packet frame length is valid with a value of 3 or greater. Of course, this value threshold can be greater than or less than 3. In response to an interrupt request from the device RF transceiver 237, the wireless pendant MPU 233 preferably determines the validity of the frame by reading and checking valid frame length and CRC data. The receive Packet RAM register is accessed when the device RF transceiver is read for data transfer. The wireless pendant RF transceiver 237 preferably transmits entire packets without intervention from the wireless pendant MPU 233. The entire packet payload is preferably pre-loaded in TX Packet RAM, the wireless pendant RF transceiver 237 transmits the frame, and then the transmit complete status is set for the wireless pendant MPU 233. When the packet is successfully transmitted, the transmit interrupt routine that runs on the device MPU 233 reports the completion of packet transmission. In response to the interrupt request from the device RF transceiver 237, the device MPU 233reads the status to clear the interrupt, and check for successful transmission.

Control of the device RF transceiver 237 and data transfers are preferably accomplished by means of a Serial Peripheral Interface (SPI) with the MPU 233. Although the normal SPI protocol is based on 8-bit transfers, the device RF transceiver 237 imposes a higher level transaction protocol that is based on multiple 8-bit transfers per transaction. A singular SPI read or write transaction preferably comprises an 8-bit header transfer followed by two 8-bit data transfers. The header denotes access type and register address. The following bytes are read or write data. The SPI also supports recursive 'data burst' transactions in which additional data transfers can occur. The recursive mode is intended for Packet RAM access and fast configuration of the device RF transceiver 237.

Figure 3 illustrates the process steps taken after system initialization. After system initialization (step 310), the wireless pendant checks for component tags in the area of the predetermined guard perimeter (step 320). At step 330, the wireless pendant obtains RF route and Link power data from all the component tags in the area. The RF data is filtered and the Link Energy is calculated at step 340. Using the Link energy, the current range from all of the component tags encountered in the area is calculated at step 350. If the wireless pendant has crossed any of the guard perimeters, alerts and alarms are generated at step 360. The process then continues so the system can be updated as the wearer moves.

Wireless Pendant Software

The software architecture for the wireless pendant device's MPU uses a interrupt-driven architecture as shown in Figure 4. The interrupt routines include timers 410 for creating the sampling frequency and handling interrupts 420 from the RF transceiver. Non-interrupt routines run on the wireless pendant MPU are system initializations and the wireless communications to the Wireless Pendant Data.

There a number of interrupt handlers that process data asynchronously from the non-interrupt main loop routine described before. One is the timer interrupt routine which is used as a time base and generates the sampling rate frequency is used by the MPU in both the wireless pendant and the wireless component tag. Another is the RF transceiver status and data transfers interrupt handler used by the MPU in both the wireless pendant and the wireless component tag devices. This routine is used to process wireless pendant or the wireless component tag device RF transceiver events, transmit route data, link energy data and control/acknowledgement data via the wireless pendant or the wireless component tag device RF transceiver to another wireless pendant or wireless component tag device or to the Wireless Pendant Data Collection server system. This routine is also used to receive wireless pendant or wireless component tag device RF transceiver route data, link energy data and control/acknowledgement data. The Wireless Pendant Data Collection server system maintains an MPU state table 430. Figure 5 is a sequence diagram of communication link protocol between the wireless pendant and the wireless component tags attached to the obstacles. The wireless pendant 510 communicates via an RF transceiver 515 with the RF transceiver 525 of each component tag 520. Initially, the wireless pendant 510 forwards a request 512 to register any component tags. AU component tags 520 respond with a registration component tag data signal 522. The wireless pendant queries whether any component tags are in the area 514. The component tag #1 acknowledges 524. The wireless pendant 520 that checks whether it has crossed or is crossing the guard perimeter for component tag #1. If so, an alert and/or alarm is generated. As the wearer moves, additional queries of component tags in the area 51 S are transmitted. These queries are acknowledged 527 by component tags in the area, such as component tag #N. At which point 519, the wireless pendant 520 that checks whether it has crossed or is crossing the guard perimeter for component tag #N. If so, an alert and/or alarm is generated. Referring to Figure 6, the wireless pendant data collection server 620 software is preferably a multithreaded Java-based server that handles one or more wireless pendant device 630A-N communications channels for data gathering, achieving and reporting. The Java language was chosen for the preferred embodiment to provide the broadest base of support for Wireless Pendant Data Collection server hardware platform. Of course, other suitable computer languages could be used. The wireless pendant data collection server 620 collects wireless pendant 630A-N time stamped alarm data with mesh-network routing information. The wireless pendant data collection server 620 collects this data via an RF transceiver 621, which is controlled by an MPU 623. The received data is forwarded to the server via personal computer interface 625. Once receiving the wireless pendant data, the wireless pendant data collection server 620 archives in a database 626 the time stamped alarm data with its mesh-network routing information for all obstacles the wireless pendant has encountered since it last reset. This data allows the wireless pendant data collection server 620 to generate traffic pattern reports for all wireless pendants 630A-N and obstacles in the area. These reports can be used, for example, for increasing area traffic efficiency, logging alarm frequency which can be a per-cursor potential accident situation with specific obstacles in the area and potential construction site compliance issues with height/location of building design components. The wireless pendant's MPU executes a default Finite Impulse Response

(FIR) software algorithm filter that is implemented using a eleventh-order moving average convolution filter whereby the filter coefficients are found via:

B(i) = 1/(P + 1) for i = 0, 1, 2, .... P

Where P = 10 for creating the eleventh-order filter. The impulse response for the resulting filter is:

h(n) = δ(n)/ll + δ(n - 1)/11 + δ(n - 2)/ll + δ(n - 3)/ll + δ(n - 4)/ll + δ(n - 5)/ll + δ(n - 6)111 + δ(n - 1)111 + δ(n - 8)/ll + δ(n - 9)111

+ δ(n - lOyil + δ(n - 11)/11

Figure 7 illustrates the block diagram of this eleventh-order filter.

The wireless pendant's MPU can also execute a dynamic sized (ordered) Finite Impulse Response (FIR) software algorithm filter based on link energy profiling requirements which is implemented using n^th-order moving average convolution filter whereby the filter coefficients are found via:

B(i) = 1/(P + 1) for i = 0, 1, 2, .... P

Where P = n - 1 for creating the n^th-order filter. The impulse response for the resulting filter is:

h(t) = δ(t)/n + δ(t - l)/n + δ(t - 2)/n + . . . . +δ(t - n )/n

Figure 8 illustrates the block diagram of this n^-order filter.

The foregoing description is of a preferred embodiment of the invention and has been presented for the purposes of illustration and description of the best mode of the invention currently known to the inventors. This description is not intended to be exhaustive or to limit the invention to the precise form, connections or choice of wireless components disclosed. Obvious modifications or variations are possible and foreseeable in light of the above teachings. This embodiment of the invention- was chosen and described to provide the best illustration of the principles of the invention and its practical application to thereby enable one of ordinary skill in the art to utilize the invention in various embodiments and with various modifications as are suited to the particular use contemplated by the inventors. All such modifications and variations are intended to be within the scope of the invention as determined by the appended claims when they are interpreted in accordance with the breadth to which they are fairly, legally and equitably entitled.

Claims

I claim:

1. A method for wireless real-time human collision avoidance using link energy power factor to determine a distance of a wearer to an obstacle comprising:

(A) wearing on a person a wireless pendant; (B) sending and monitoring, by the wireless pendant, mesh-type network packet data to and from complementary wireless component tags attached to obstacles;

(C) signal averaging and temporally smoothing the collected wireless component tag RP packet power factor data using dynamically sized moving average convolution filters and storing the results at the wireless pendant;

(D) using the signal averaging and temporally smoothing results to create a Link Energy LE(x,y,z,t) result, which is ∑jp(x,y,z)*dt, where P(x,y,z) is a Radio Frequency (RF) power factor of a spread-spectrum sensor network link packet received at the point defined by the x,y,z coordinates as defined in LE(x,y,z,t); (E) correlating, by the wireless pendant, the Link Energy LE(x,y,z,t) results from (D) with a near-field or far-field RF energy-to-range/distance profile table to derive various coefficients and using the derived coefficients to calculate the current distance for the wireless pendant to the wireless component tags attached obstructions.

2. The method of claim 1, further comprising:

(F) creating guard perimeters with wireless component tags attached to obstructions/obstacles and tracking up to 2048 wireless component tags in real-time;

(G) generating an alert/alarm which is time stamped and archived when this wireless pendant which is worn by a human/person crosses the guard perimeters of wireless component tags known to this wireless pendant;

(H) collecting, by the wireless pendant data collection server, any or all wireless pendant time stamped alert/alarm data with mesh-network routing information, archiving the collected data, and generating traffic pattern reports for all wireless pendants and obstructions/obstacles in the area.

3: The method of claim 1, wherein said real-time human collision avoidance uses a wireless mesh-type network for extreme data reliability.

4. The method of claim 1, wherein said wireless component tags are attached to obstructions/obstacles that are to be avoided by persons wearing the wireless pendant.

5. The method of claim 1, wherein said a wireless pendant and wireless component tags are used that use wireless mesh-network spread-spectrum links and the wireless pendant algorithmically determines the distance/range between it and the wireless component tags in real-time.

6. The method of claim 1 , wherein said wireless pendants and wireless component tags are used to protect personal (humans/persons) in a building site under construction that contain obstructions/obstacles to be avoided.

7. The method of claim 1, wherein said wireless pendants and wireless component tags are used to protect personal (humans/persons) in areas of low or no light conditions that contain obstructions/obstacles to be avoided.

8. The method of claim 1, wherein said wireless pendants and wireless component tags are used to protect personal (humans/persons) with serve vision problems in areas that contain obstructions/obstacles to be avoided.

9. The method of claim 1, wherein said wireless pendants and wireless component tags are used to protect personal (humans/persons) from low-height basements and/or low-hanging construction such as beams, pipes and ceilings which are desired obstructions/obstacles to be avoided.

10. The method of claim 1, wherein said wireless pendants and wireless component tags are used to protect wearers from areas that contain dangerous conditions.

11. The method of claim 1, wherein said wireless pendants are used with a wireless pendant data collection server to profile and correlate the spatial-temporal alerts/alarms of all wireless pendants worn by all the humans/persons in the designated area containing the obstructions/obstacles that are to be avoided.