Doppler based cellular navigation system

1 . A Doppler based cellular navigation system, the system comprising:

a radio frequency (RF) antenna;

an RF receiver in communication with the RF antenna;

a memory including ground-based RF emitter database with ground-based RF emitter location information; and

a controller in communication with the RF receiver and the memory, the controller configured to monitor a Doppler shifts in received RF signals from ground-based RF emitters through the RF antenna, the controller further configured to determine both range and bearing to each ground-based RF emitter by measuring a rate of change of a doppler shift when the frequency of and associated received signal is equal to a known transmit frequency of the received RF signal, the controller further configured to determine location information using the determined range from at least two spaced ground-based RF emitters and determining an intersection of at least two circles and lines of position associated with the at least two spaced ground-based RF emitters, the controller further configured to implement the determined location information in navigating a vehicle.

2 . The system of claim 1 , wherein the controller is configured to determine the location information relating to the vehicle by identify a discrete frequency band associated with received RF signal and looking up location information of a ground-based RF emitter associated with the discrete frequency band in the ground-based RF emitter database.

3 . The system of claim 1 , further comprising:

at least one other navigation system, the controller configured to supplement the location information from the at least one other navigation system with the determined location information from the Doppler based cellular navigation system.

4 . The system of claim 3 , wherein the at least one other navigation system is a global navigation satellite system (GNSS) and the determined location information by the Doppler based cellular navigation system is used during non-satellite signal coverage periods.

5 . The system of claim 4 , wherein the GNSS comprises:

a GNSS receiver in communication with a GNSS antenna, the controller in communication with the GNSS receiver.

6 . The system of claim 3 , wherein the at least one other navigation system is an inertial navigation system (INS) and the determined location information by the Doppler based cellular navigation system is used to correct for drift in INS measurements.

7 . The system of claim 1 , further comprising:

a communication system in communication with the controller, the controller configured to cause the communication system to communicate location information of detected ground-based RF emitters to a remote location.

8 . The system of claim 1 , wherein the communicated location information includes at least a frequency of the RF signals generated by a detected ground-based RF emitter and a location of the detected ground-based RF emitter.

9 . The system of claim 1 , further comprising:

a vehicle control system in communication with the controller, the vehicle control system configured to control the navigation of the vehicle based at least in part on the determined location information when the controller detects a Doppler shift in the received RF signal of zero.

10 . A method of determining a location of a vehicle with a Doppler based cellular navigation system, the method comprising:

identifying ground-based radio frequency (RF) emitters in a travel path of vehicle using a ground-based radio RF emitter database and RF signals transmitted by the RF emitters that are received through an RF antenna of the vehicle;

measuring a rate of change of a Doppler shift in the received signal RF signals from the identified ground-based RF emitters as the vehicle continues in the travel path to determine both range and bearing to each identified ground-based RF emitter;

determining a vehicle closest position to associated ground-based RF emitters when the Doppler shift reaches zero;

using the determined range to at least two spaced ground-based RF emitters of the identified ground-based RF emitters and an intersection of at least two circles and lines of position associated with the at least two spaced ground-based RF emitters to determine location information; and

using the determined location information at least in part for the navigation of the vehicle.

11 . The method of claim 10 , further comprising:

increasing a determined location accuracy of the vehicle by measuring the received RF signals from more than two ground-based RF emitters.

12 . The method of claim 10 , wherein the ground-based RF emitter is part of a cellular base station.

13 . The method of claim 10 , further comprising:

using an inertial navigation system to at least in part determine an inertial determined position of the vehicle.

14 . The method of claim 13 , further comprising:

correcting for drift in the inertial navigation system based at least in part on the monitoring of the Doppler shift.

15 . The method of claim 10 , wherein determining the location of the vehicle is done with at least one of determining a signal strength, determining a relative angle to the ground-based RF emitter, and using a rate of change of the Doppler shift.

16 . The method of claim 10 , further comprising:

gathering ground-based RF emitter information with the vehicle as the vehicle traverses the travel path when the received signal is not associated with a ground-based RF emitter already in the ground-based radio RF emitter database, the ground-based RF emitter information including at least frequency of the RF signal used by the ground-based RF emitter and location of the ground-based RF emitter; and

using the gathered ground-based RF emitter information at least in part to generate the ground-based RF emitter database.

17 . The method of claim 16 , further comprising:

sharing the gathered ground-based RF emitter information;

generating the ground-based RF emitter database based at least in part on the shared gathered ground-based RF emitter information at a remote location; and

disseminating the ground-based RF emitter database to other vehicles.

18 . A method of determining a location of a vehicle with a Doppler based cellular navigation system, the method comprising:

monitoring radio frequency (RF) signals with an RF receiver that are received by an RF antenna of the vehicle;

identifying a discreate frequency band used by a each detected RF signal;

identifying each ground-based RF emitter based on an identified discrete frequency band;

obtaining ground-based RF emitter information regarding identified ground-based RF emitters from a ground-based RF emitter database;

measuring the rate change of a detected Doppler frequency shift in the detected RF signals;

determining location information of the vehicle at least in relation to at least two identified ground-based RF emitters based on at least the obtained ground-based RF emitter information and when the monitored frequency of the received signal is equal to a known transmit frequency of a ground-based RF emitter; and

using the determined location at least in part for the navigation of the vehicle.

19 . The method of claim 18 , further comprising:

supplementing at least one navigation system based on the determined location information.

20 . The method of claim 18 , further comprising:

increasing a determined location information accuracy of the vehicle by monitoring a Doppler shift in plurality of RF signals from more than two ground-based RF emitters.