Correcting frequency errors in frequency difference of arrival geolocation systems
First Claim
1. A computer-implemented method comprising:
- receiving a target signal at a first collector;
receiving the target signal at a second collector;
determining a frequency of the target signal at the first collector based upon, at least in part, a first reference timebase source associated with the first collector;
determining an intended frequency of a reference carrier signal at the first collector based upon, at least in part, the first reference timebase source associated with the first collector;
determining a frequency of the target signal at the second collector based upon, at least in part, a second reference timebase source associated with the second collector;
determining an observed frequency of the reference carrier signal at the second collector based upon, at least in part, the second reference timebase source associated with the second collector;
calculating a relative timebase error between the first collector and the second collector based upon, at least in part, a difference between the intended frequency of the reference carrier signal and the observed frequency of the reference carrier signal;
calculating a corrected frequency difference for the target signal based upon, at least in part, the relative timebase error and a proportional scaling factor; and
geolocating a source of the target signal based upon, at least in part, calculated time difference of arrival and frequency difference of arrival of the target signal at the first collector and at the second collector and based upon, at least in part, the calculated corrected frequency difference for the target signal.
1 Assignment
0 Petitions
Accused Products
Abstract
A frequency correction for frequency difference of arrival geolocation of transmitted target signals may be provided. A frequency of a target signal may be determined at a first collector based upon a first reference timebase source. A frequency of the target signal may be determined at a second collector based upon a second reference timebase source. An observed frequency of a reference carrier signal based upon the first reference timebase source may be determined at the second collector based upon the second reference timebase source. A relative timebase error between the first collector and the second collector may be calculated based upon a difference between the intended frequency of the reference carrier signal and the observed frequency of the reference carrier signal. A corrected frequency difference for the target signal may be calculated based upon the relative timebase error and a proportional scaling factor.
11 Citations
27 Claims
-
1. A computer-implemented method comprising:
-
receiving a target signal at a first collector; receiving the target signal at a second collector; determining a frequency of the target signal at the first collector based upon, at least in part, a first reference timebase source associated with the first collector; determining an intended frequency of a reference carrier signal at the first collector based upon, at least in part, the first reference timebase source associated with the first collector; determining a frequency of the target signal at the second collector based upon, at least in part, a second reference timebase source associated with the second collector; determining an observed frequency of the reference carrier signal at the second collector based upon, at least in part, the second reference timebase source associated with the second collector; calculating a relative timebase error between the first collector and the second collector based upon, at least in part, a difference between the intended frequency of the reference carrier signal and the observed frequency of the reference carrier signal; calculating a corrected frequency difference for the target signal based upon, at least in part, the relative timebase error and a proportional scaling factor; and geolocating a source of the target signal based upon, at least in part, calculated time difference of arrival and frequency difference of arrival of the target signal at the first collector and at the second collector and based upon, at least in part, the calculated corrected frequency difference for the target signal. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9)
-
-
10. A computer program product comprising a computer readable medium having a plurality of instructions stored thereon, which, when executed by a processor, cause the processor to perform operations including:
-
receiving a target signal at a first collector; receiving the target signal at a second collector; determining a frequency of the target signal at the first collector based upon, at least in part, a first reference timebase source associated with the first collector; determining an intended frequency of a reference carrier signal at the first collector based upon, at least in part, the first reference timebase source associated with the first collector; determining a frequency of the target signal at the second collector based upon, at least in part, a second reference timebase source associated with the second collector; determining an observed frequency of the reference carrier signal at the second collector based upon, at least in part, the second reference timebase source associated with the second collector; calculating a relative timebase error between the first collector and the second collector based upon, at least in part, a difference between the intended frequency of the reference carrier signal and the observed frequency of the reference carrier signal; calculating a corrected frequency difference for the target signal based upon, at least in part, the relative timebase error and a proportional scaling factor; and geolocating a source of the target signal based upon, at least in part, calculated time difference of arrival and frequency difference of arrival of the target signal at the first collector and at the second collector and based upon, at least in part, the calculated corrected frequency difference for the target signal. - View Dependent Claims (11, 12, 13, 14, 15, 16, 17, 18)
-
-
19. A computing system comprising:
-
a processor and a memory module coupled with the processor, the processor being configured for; determining a frequency of a target signal received at a first collector based upon, at least in part, a first reference timebase source associated with the first collector; determining an intended frequency of a reference carrier signal at the first collector based upon, at least in part, the first reference timebase source associated with the first collector; determining a frequency of the target signal received at a second collector based upon, at least in part, a second reference timebase source associated with the second collector; determining an observed frequency of the reference carrier signal at the second collector based upon, at least in part, the second reference timebase source associated with the second collector; calculating a relative timebase error between the first collector and the second collector based upon, at least in part, a difference between the intended frequency of the reference carrier signal and the observed frequency of the reference carrier signal; calculating a corrected frequency difference for the target signal based upon, at least in part, the relative timebase error and a proportional scaling factor; and geolocating a source of the target signal based upon, at least in part, calculated time difference of arrival and frequency difference of arrival of the target signal at the first collector and at the second collector and based upon, at least in part, the calculated corrected frequency difference for the target signal. - View Dependent Claims (20, 21, 22, 23, 24, 25, 26, 27)
-
Specification