A multitarget tracking antispoofing receiver utilizes multitarget tracking algorithms and multiple correlators for tracking signals of interest in a field of view about a nominal trajectory of a desired true signal for tracking targets within the code phase and carrier frequency signal space so as t
A multitarget tracking antispoofing receiver utilizes multitarget tracking algorithms and multiple correlators for tracking signals of interest in a field of view about a nominal trajectory of a desired true signal for tracking targets within the code phase and carrier frequency signal space so as to predict when true and spoof signals will cross paths in the signal space without spoofing with loss of tracking of the desired signal so that true tracking of a desired target is maintained in the presence of a spoofing signal moving along a spoofing signal track and crossing a true path of the true signal.
대표청구항▼
What is claimed is: 1. A system for tracking a first signal in a code phase and carrier frequency signal space in the presence of a second signal in the same code phase and carrier frequency signal space, the system comprising correlators for defining the code phase and carrier frequency signal spa
What is claimed is: 1. A system for tracking a first signal in a code phase and carrier frequency signal space in the presence of a second signal in the same code phase and carrier frequency signal space, the system comprising correlators for defining the code phase and carrier frequency signal space having a field of view encompassing the presence of the first signal and the second signal when not overlapping each other within the code phase and carrier frequency signal space, the first and second signals having the same carrier frequency and code phase defining the code phase and carrier frequency signal space, the first and second signals having different code phase offsets and carrier frequency offsets when not overlapping each other but remaining within the code phase and carrier frequency signal space, a detector for detecting the first and second signals in the code phase and carrier frequency signal space when not overlapping in the code phase and carrier frequency signal space, and a tracker for concurrently tracking the first signal and second signal in the code phase and carrier frequency signal space when the first signal and the second signal are and are not overlapping in the code phase and carrier frequency signal space. 2. The system of claim 1 wherein, the code phase and carrier frequency signal space is defined by a range of the code phase offsets and a range of the carrier frequency offsets, the tracker tracks the code phase and carrier frequency as the code phase offsets and carrier frequency offsets of the first and second signal change over time, the tracker is a multitarget tracker when tracking both the first signal and the second signal in the code phase and carrier frequency signal space, and the first signal and the second signal cross over each other at a cross over point in the code phase and carrier frequency signal space where the first signal and the second signal have the same code phase offset and carrier frequency offset when overlapping each other. 3. The system of claim 1 wherein the tracker implements a multitarget algorithm for assigning the first signal and the second signal to respective first and second hypothesized tracks in the code phase and carrier frequency signal space at a time before the first signal and the second signal overlap each other in the code phase and carrier frequency signal space, and, for assigning the first signal and the second signal to the respective hypothesized tracks after the time when the first signal and the second signal overlap each other in the code phase and carrier frequency signal space, so as to not confuse the tracking of the second signal with the tracking of the first signal in the code phase and carrier frequency signal space, and, in the event that the two signals never overlap but remain in close proximity in the code phase and carrier frequency signal space, the tracker uses the multitarget algorithm to distinguish between the the first and second signals from their relative positions and the first and second hypothesized tracks. 4. The system of claim 1 wherein, the code phase and carrier frequency signal space maintains at a center position an estimate of the code phase and carrier frequency of the first signal, the center position of the code phase and carrier frequency signal space is updated, using relevant data including pseudorange, pseudorange rate, and clock error, as the code phase offset and carrier frequency offset of the first signal changes over time, and the data to update the center position of the code phase and carrier frequency signal space comes from the tracking of the first signal and from the processing of inertial measurement and GPS sample data. 5. The system of claim 1, further comprising, a navigation calculator for receiving inertial measurement data and for determining position and motion of the system for adjusting a code phase offset of a replica code and for adjusting a carrier frequency offset of a replica carrier that are both fed to the correlators for maintaining coherent correlation of the first signal and the second signal. 6. The system of claim 1 wherein, the first signal is a GPS signal consisting of a series of message bits modulated by a pseudorandom noise chipping code and also modulated by a carrier frequency, the first signal, when sufficiently separated from the second signal in the code phase and carrier frequency signal space, uses the tracking system as a predictable series of code phase offset and carrier frequency offset measurements, and the first signal, at a given time, has unpredictable code phase offset and carrier frequency offset measurements, due to the second signal overlapping the first signal in the code phase and carrier frequency signal space, the first signal continually being tracked and resolved by the tracking system. 7. The system of claim 1 wherein, the second signal is selected from the group consisting of undesired signals and interfering signals and jamming signals and spoofing signals, the second signal will be recognized as predictably changing code phase offset and carrier frequency offset measurements over time, by the tracking system and will be distinguished from the first signal by these predictable code phase offset and carrier frequency offset measurements, and the second signal having code phase offset and carrier frequency offset measurements that are disjointed being uncorrelated over time and unpredictable, and the disjointed code phase offset and carrier frequency offset measurements will be prevented from corrupting the track of the first signal because these unpredictable and disjointed measurements do not, over time, fit a model given by the track of the first signal. 8. A system for tracking a first signal in a spreading code and carrier frequency signal space in the presence of a second signal in the same code phase and carrier frequency signal space, the system comprising correlators for defining the code phase and carrier frequency signal space having a field of view encompassing the presence of the first signal and the second signal when not overlapping each other within the code phase and carrier frequency signal space, the first and second signals having the same code phase and carrier frequency defining the code phase and carrier frequency signal space, the first and second signals having different code phase offsets and carrier frequency offsets when not overlapping each other but remaining within the code phase and carrier frequency signal space, a detector for detecting the first and second signals in the code phase and carrier frequency signal space when not overlapping in the code phase and carrier frequency signal space, and a tracker for concurrently tracking the first signal and second signal in the code phase and carrier frequency signal space when the first signal and the second signal are and are not overlapping in the code phase and carrier frequency signal space, wherein, the tracker implements a multitarget algorithm for assigning the first signal and the second signal to respective first and second hypothesized tracks in the code phase and carrier frequency signal space at a time before the first signal and the second signal overlap each other in the code phase and carrier frequency signal space, and, for assigning the first signal and the second signal to the respective hypothesized tracks after the time when the first signal and the second signal overlap each other in the code phase and carrier frequency signal space, so as to not confuse the tracking of the second signal with the tracking of the first signal in the code phase and carrier frequency signal space, and, in the event that the two signals are in close proximity to each other in the code phase and carrier frequency signal space, the tracker uses the multitarget algorithm to distinguish between the two signals from their relative positions and the hypothesized tracks.
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이 특허에 인용된 특허 (9)
Zscheile ; Jr. John W. (Farmington UT) Lundquist Alan E. (Salt Lake City UT) Spencer Billie M. (Bountiful UT), Burst jammer erasure circuit for spread spectrum receivers.
Loomis,Peter Van Wyck; Yu,Yiming, Signal receiver using coherent integration in interleaved time periods for signal acquisition at low signal strength.
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