Patent ID: 9466216
Filing Date: 2016-10-11
CPC Classification: B60Q,F16P,G08B,G08G

Claim Text:
1. A system, comprising: a vehicle; a generator that generates a magnetic field, the generator being configured to receive response signals; and an alarm device that sends response signals, the alarm device being configured to sense the magnetic field and generate 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 second predetermined time period comprises a plurality of time portions; wherein the alarm device generates a radio frequency 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 radio frequency 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 less than the second strength, the first length of time is shorter than the second length of time, and the radio frequency response signal of the first length of time appears in less than all of the plurality of the time portions and the radio frequency response signal of the second length of time appears in all of the plurality of time portions, wherein the system is a collision avoidance system.