Vehicle locator key fob with range and bearing measurement
An apparatus and method of determining bearing and distance measurements between a mobile device and an object using Rf based measurements. The mobile device communicates with a control in the object to determine the relative bearing between the mobile device and the object with respect to magnetic north and, optionally, the distance between the mobile device and the object. An indicator on the mobile device aid in directing s the user of the mobile device toward the object as the mobile device is moved relative to the object. The mobile device can be a key fob and the object can be a vehicle.
1. An object location apparatus comprising:
a control adapted to be mounted on an object to transmit and receive circumferential, rotating wireless signals with respect to a remote mobile device;
a transmitter and a receiver coupled to the control;
the mobile device having a transmitter and a receiver; and
one input member carried on the mobile device for activating a location determining sequence in the mobile device and the control to aid the user of the mobile device in locating the object.
2. The apparatus of claim 1 further comprising:
an antenna, responsive to the control, for generating said angularly rotating signal containing signal angle information relative to magnetic north; and
the mobile device operative to detect the angularly rotating signal and to decode the signal angle information in the angularly rotating signal to determine a bearing relative to magnetic north between the mobile device and the object.
3. The apparatus of claim 1 further comprising:
the mobile device operative to determine an approximate distance between the mobile device and the object.
4. The apparatus of claim 3 wherein:
the mobile device determines the distance by determining the time delay of a signal transmission from the mobile device to the object and a return signal from the object to the mobile device.
5. The apparatus of claim 3 wherein:
the mobile device determines the distance of determining the signal strength of a return signal from the object to the mobile device.
6. The apparatus of claim 1 further comprising:
an indicator carried on the mobile device for providing direction information including at least the relative bearing to the user of the mobile device to provide the location of the object relative to the mobile device.
7. The apparatus of claim 6 further comprising:
the mobile device operative to update the direction information as the mobile device is moved relative to the object.
8. The apparatus of claim 6 wherein the indicator comprises:
a visual display carried on the mobile device and providing geographic location information including a bearing path between the mobile device and the object.
9. The apparatus of claim 6 wherein the indicator comprises:
at least one illuminatable element carried on the mobile device for indicating when the user of the mobile device is moving on a substantially direct path to the object as the mobile device is moved relative to the object.
10. The apparatus of claim 9 wherein the at least one illuminatable element comprises:
a plurality of light emitting diodes carried on the mobile device for indicating relative separation of the user of the mobile device from a direct path between the mobile device and the object as the mobile device is moved relative to the object.
11. The apparatus of claim 1 wherein:
the object is a vehicle; and
the mobile device is a portable key fob.