Performance improvements for measurement of opportunity geolocation/navigation systems
A system and method of determining the location of a mobile device using signals of opportunity, derived time stamps and sharing of signal information with other mobile devices.
1. A method of determining the location of a mobile device:
(a) receiving a first signal of opportunity (SoOP) at a mobile device, wherein the SoOP is an ambient radio frequency (RF) transmission that is not intended for navigation, position or timing for positioning purposes and the mobile device does not include a timing reference having precision to determine the latitude and longitude location of the mobile device and wherein the first signal does not contain a timing reference, and wherein the first SoOP is transmitted from a system different than the communication system of the mobile device;
(b) receiving a second signal at the mobile device, wherein the second signal includes a timing reference that provides a first time stamp for receipt of the second signal;
(c) sampling the first SoOP and digitizing a portion of it;
(d) deriving a second time stamp for the first SoOP based on the first time stamp of the second signal; and
(e) using the digitized portion of the first SoOP with the derived second time stamp for the first signal to determine the location of the mobile device.
2. The method of claim 1 wherein the first SoOP is a mobile telephone signal and the second signal is a satellite navigation signal.
3. The method of claim 1 wherein the step of using the digitized portion of the first SoOP with the derived first time stamp to determine the location of the mobile device includes receiving additional signals having respective time stamps at the mobile device and determining the location of the mobile device from the digitized portion of the first SoOP with the derived first time stamp and the additional signals having respective time stamps.
4. The method of claim 3 wherein the location of the mobile is determined using time difference of arrival methods.
5. The method of claim 3 wherein the location of the mobile device is determined using time of arrival methods.
6. The method of claim 3 wherein the location of the mobile device is determined by the mobile device.
7. The method of claim 3 wherein the digitized portion of the first SoOP with the derived first time stamp and the additional signals having respective time stamps are sent to a central processor and the central processor determines the location of the mobile device.
8. The method of claim 3 wherein the mobile device is one of a mobile phone, a laptop, a tablet, a personal digital assistant, or a navigation device.
9. A system for determining the location of a mobile device:
a mobile device wherein the mobile device does not include a timing reference having precision to determine the latitude and longitude location of the mobile device, including:
a memory for storing computer readable code; and
a processor operatively coupled to the memory, the processor configured to:
receive a first signal of opportunity (SoOP), wherein the SoOP is an ambient radio frequency (RF) transmission that is not intended for navigation, position or timing for positioning purposes and wherein the first SoOP does not contain a timing reference;
receive a second signal at the mobile device, wherein the second signal includes a timing reference to provide a first time stamp for receipt of the second signal;
sample the first SoOP and digitizing a portion of it;
derive a second time stamp for the first SoOP based on the first time stamp of the second signal; and
determine the location of the mobile device using the digitized portion of the first SoOP with the derived first time stamp for the first SoOP.
10. The system of claim 9 wherein the first SoOP is a mobile telephone signal and the second signal is a satellite navigation signal.
11. The system of claim 9 wherein the processor is further configured to receive additional signals having respective time stamps at the mobile device and determining the location of the mobile device from the digitized portion of the first SoOP with the derived first time stamp and the additional signals having respective time stamps.
12. The system of claim 11 wherein processor is further configure to determine the location of the mobile device using time difference of arrival.
13. The system of claim 9 wherein the mobile device is one of a mobile phone, a laptop, a tablet, a personal digital assistant, or a navigation device.