Proximity detection system

A collision avoidance system, comprising:

• a vehicle;
• a generator that generates a magnetic field, the generator being capable of receiving response signals;
• and
• an alarm device that sends response signals, the alarm device being capable of sensing the magnetic field and generating a response signal;
• wherein the generator generates said magnetic field for a first predefined time period, and senses for a response signal from the alarm device within a second predefined time period;
• wherein the alarm device generates a response signal of a first length of time when the alarm device detects the magnetic field at a first strength,
• wherein the alarm device generates a response signal of a second length of time when the alarm device detects the magnetic field at a second strength, and
• wherein the first strength is different from the second strength and the first length of time is different from the second length of time.

A method for avoiding collision, comprising the steps of:

• generating a magnetic field for a first predefined time period;
• sensing the magnetic field and generating a response signal, the response signal being a first length of time when the alarm device detects the magnetic field at a first strength, and the response signal being a second length of time when the alarm device detects the magnetic field at a second strength;
• and
• sensing for the response signal within a second predefined time period;
• wherein the first strength is different from the second strength and the first length of time is different from the second length of time.

A proximity detection system for complex work environments for detecting the presence of a worker or operator wearing an alarm device in a potentially hazardous location at a work site, the proximity detection system comprising:

• a plurality of vehicles;
• each of the vehicles having a plurality of magnetic field generators;
• each of the plurality of magnetic field generators adapted to generate ping pulses of a magnetic field;
• a plurality of alarm devices located on the persons of a plurality of workers and/or operators, each device being adapted to sense the ping pulse magnetic field in which the device is located and generate an echo response signal after a predetermined echo time delay;
• the plurality of magnetic field generators being adapted to receive the echo response signals, and in response to receiving the echo response signal during a window of time corresponding to the predetermined echo time delay, to generate a burst of the magnetic field ping pulses, the burst of ping pulses being of predetermined duration and being generated at semi-random time intervals;
• the plurality of magnetic field generators being adapted to, in response to receiving the echo response signal during a window of time corresponding to the predetermined echo time delay for each of the ping pulses of the burst, identify that the device is located in a particular magnetic field generated by one of the plurality of magnetic field generators.

A method for detecting proximity for complex work environments for detecting the presence of a worker or operator wearing an alarm device in a potentially hazardous location at a work site having a plurality of vehicles, comprising the steps of:

• providing each of the vehicles with a plurality of magnetic field generators each of the plurality of magnetic field generators adapted to generate ping pulses of a magnetic field;
• generating with a magnetic field generator ping pulses of a magnetic field;
• providing a plurality of alarm devices located on the persons of a plurality of workers and/or operators, each device being sensing the ping pulse magnetic field in which the device is located and generate an echo response signal after a predetermined echo time delay;
• the plurality of magnetic field generators receiving the echo response signals, and in response to receiving the echo response signal during a window of time corresponding to the predetermined echo time delay, generating a burst of the magnetic field ping pulses, the burst of ping pulses being of predetermined duration and being generated at semi-random time intervals;
• the plurality of magnetic field generators, in response to receiving the echo response signal during a window of time corresponding to the predetermined echo time delay for each of the ping pulses of the burst, identifying that the device is located in a particular magnetic field generated by one of the plurality of magnetic field generators.

A proximity detection system for complex work environments for detecting the presence of a worker or operator wearing an alarm device in a potentially hazardous location at a work site, the proximity detection system comprising:

• at least a first, second, and third magnetic field generator;
• each of the first, second, and third magnetic field generators adapted to generate ping pulses of a first, second, and third magnetic field, respectively, the first, second, and third magnetic fields having an overlapping area and oscillating at low frequency during each ping pulse, the ping pulses having predetermined pulse durations and being generated at first semi-random time intervals;
• a plurality of alarm devices, each device being adapted to sense the strength of the ping pulse magnetic field in which the device is located and to generate an echo response signal after a predetermined echo time delay, wherein the length of the predetermined echo time delay or the length of the echo response signal is based on the sensed strength of the ping pulse magnetic field;
• the first, second, and third magnetic field generators being adapted to receive the echo response signals, and in response to receiving the echo response signal during a window of time corresponding to the predetermined echo time delay, to generate a burst of the magnetic field ping pulses, the burst of ping pulses being of predetermined duration and being generated at second semi-random time intervals, the second semi-random time intervals being shorter than the first semi-random time intervals;
• the first, second, and third magnetic field generators being adapted to, in response to receiving the echo response signal during a window of time corresponding to the predetermined echo time delay for each of the ping pulses of the burst, identify that the device is located in the first, second, and/or third magnetic field, and to, based on the length of the predetermined echo time delay or the length of the echo response signal, identify that the device is located in a particular one of a plurality of zones of the first, second, and/or third magnetic field, each zone being smaller than the magnetic field;
• wherein each of said plurality of alarm devices issues a first type of alarm when it senses a first zone of the first or second magnetic field and wherein each of said plurality of alarm devices issues a second type of alarm when it senses the first zone of both the first and second magnetic fields;
• and
• wherein each of said plurality of alai in devices issues an alarm when it senses at least one of the first and second magnetic fields and not the third magnetic field, and wherein each of said plurality of alarm devices does not issue an alarm when it senses the third magnetic field only or in addition to the at least one of the first and second magnetic fields.

A method for complex work environments for detecting the presence of a worker or operator wearing an alarm device in a potentially hazardous location at a work site, comprising the steps of:

• each of the first, second, and third magnetic field generators generating ping pulses of a first, second, and third magnetic field, respectively, the first, second, and third magnetic fields having an overlapping area and oscillating at low frequency during each ping pulse, the ping pulses having predetermined pulse durations and being generated at first semi-random time intervals;
• a plurality of alarm devices, each sensing the strength of the ping pulse magnetic field in which the device is located and generating an echo response signal after a predetermined echo time delay, wherein the length of the predetermined echo time delay or the length of the echo response signal is based on the sensed strength of the ping pulse magnetic field;
• the first, second, and third magnetic field generators receiving the echo response signals, and in response to receiving the echo response signal during a window of time corresponding to the predetermined echo time delay, generating a burst of the magnetic field ping pulses, the burst of ping pulses being of predetermined duration and being generated at second semi-random time intervals, the second semi-random time intervals being shorter than the first semi-random time intervals;
• the first, second, and third magnetic field generators, in response to receiving the echo response signal during a window of time corresponding to the predetermined echo time delay for each of the ping pulses of the burst, identifying that the device is located in the first, second, and/or third magnetic field, and to, based on the length of the predetermined echo time delay or the length of the echo response signal, identifying that the device is located in a particular one of a plurality of zones of the first, second, and/or third magnetic field, each zone being smaller than the magnetic field;
• each of said plurality of alarm devices issuing a first type of alai when it senses a first zone of the first or second magnetic field and each of said plurality of alarm devices issuing a second type of alarm when it senses the first zone of both the first and second magnetic fields;
• and
• wherein each of said plurality of alarm devices issuing an alarm when it senses at least one of the first and second magnetic fields and not the third magnetic field, and each of said plurality of alarm devices not issuing an alarm when it senses the third magnetic field only or in addition to the at least one of the first and second magnetic fields.

A proximity detection system for reducing false alarms in complex work environments for detecting the presence of a worker or operator wearing an alarm device in a potentially hazardous location at a work site, the proximity detection system comprising:

• a plurality of vehicles;
• each of the vehicles having a plurality of magnetic field generators;
• each of the plurality of magnetic field generators adapted to generate ping pulses of a magnetic field, the magnetic field oscillating at low frequency during each ping pulse, the ping pulses having predetermined pulse durations and being generated at first semi-random time intervals;
• a plurality of alarm devices located on the persons of a plurality of workers and/or operators, each device being adapted to sense the ping pulse magnetic field in which the device is located and generate an echo response signal after a predetermined echo time delay;
• the plurality of magnetic field generators being adapted to receive the echo response signals, and in response to receiving the echo response signal during a window of time corresponding to the predetermined echo time delay, to generate a burst of the magnetic field ping pulses, the burst of ping pulses being of predetermined duration and being generated at second semi-random time intervals, the second semi-random time intervals being shorter than the first semi-random time intervals;
• the plurality of magnetic field generators being adapted to, in response to receiving the echo response signal during a window of time corresponding to the predetermined echo time delay for each of the ping pulses of the burst, identify that the device is located in a particular magnetic field generated by one of the plurality of magnetic field generators and send alarm signals only to the device and the corresponding vehicle.

A method for reducing false alarms in a proximity detection system for complex work environments for detecting the presence of a worker or operator wearing an alarm device in a potentially hazardous location at a work site having a plurality of vehicles, comprising the steps of:

• providing each of the vehicles with a plurality of magnetic field generators;
• each of the plurality of magnetic field generators generating ping pulses of a magnetic field, the magnetic field oscillating at low frequency during each ping pulse, the ping pulses having predetermined pulse durations and being generated at first semi-random time intervals;
• a plurality of alarm devices located on the persons of a plurality of workers and/or operators, each device sensing the ping pulse magnetic field in which the device is located and generating an echo response signal after a predetermined echo time delay;
• the plurality of magnetic field generators receiving the echo response signals, and in response to receiving the echo response signal during a window of time corresponding to the predetermined echo time delay, generating a burst of the magnetic field ping pulses, the burst of ping pulses being of predetermined duration and being generated at second semi-random time intervals, the second semi-random time intervals being shorter than the first semi-random time intervals;
• the plurality of magnetic field generators, in response to receiving the echo response signal during a window of time corresponding to the predetermined echo time delay for each of the ping pulses of the burst, identifying that the device is located in a particular magnetic field generated by one of the plurality of magnetic field generators and sending alarm signals only to the device and the corresponding vehicle.

A proximity detection system for controlling a vehicle, comprising:

• a vehicle;
• a generator that generates a magnetic field, the generator being capable of receiving response signals;
• and
• an alarm device that sends response signals, the alarm device being capable of sensing the magnetic field and generating a response signal;
• wherein the generator generates said magnetic field for a first predefined time period, and senses for a response signal from the alarm device within a second predefined time period;
• wherein the alarm device generates a response signal of a first length of time when the alarm device detects the magnetic field at a first strength,
• wherein the alarm device generates a response signal of a second length of time when the alarm device detects the magnetic field at a second strength,
• wherein the first strength is different from the second strength and the first length of time is different from the second length of time;
• and
• the generator being capable of generating an alarm signal to the operator of the vehicle and of sending a signal to shut down the vehicle, upon sensing a response signal of a predetermined strength.

A method of controlling a vehicle in a proximity detection system, comprising the steps of:

• a generator generating a magnetic field, the generator receiving response signals;
• and
• an alarm device alarm device sensing the magnetic field and generating a response signal;
• wherein the generator generates said magnetic field for a first predefined time period, and senses for a response signal from the alarm device within a second predefined time period;
• wherein the alarm device generates a response signal of a first length of time when the alarm device detects the magnetic field at a first strength,
• wherein the alarm device generates a response signal of a second length of time when the alarm device detects the magnetic field at a second strength,
• wherein the first strength is different from the second strength and the first length of time is different from the second length of time;
• and
• the generator generating an alarm signal to the operator of the vehicle and of sending a signal to shut down the vehicle, upon sensing a response signal of a predetermined strength.