US-12621063-B2 - Systems and methods for flexible time based waveform synthesis

Abstract

The present application at least describes a method for waveform synthesis. The method may include a step of transmitting a stimulus signal to a software defined radio (SDR) operating in a first state. The method may also include a step of receiving, via the SDR, an output signal based upon the transmitted stimulus signal. The method may also include a step of. determining, based upon the received output signal, a delay state of the SDR from a plurality of predetermined delay states of the SDR. The delay state may be associated with a parameter of the SDR. The parameter may include any one or more of a receive frequency, transmit frequency or bandwidth. The method may further include a step of generating a calibrated signal based upon the determined delay state. The method may even further include a step of sending the calibrated signal to the SDR to adjust a time.

Inventors

• Bahman GORJIDOOZ
• Bradley J. Ramsey
• Jeremy Dean Warriner

Assignees

• CACI, Inc.—Federal

Dates

Publication Date

20260505

Application Date

20230817

Claims (19)

1. 1 . A method comprising: transmitting a stimulus signal to a software defined radio (SDR) operating in a first state; receiving, via the SDR, an output signal based upon the transmitted stimulus signal; determining, based upon the received output signal, a delay state of the SDR from a plurality of predetermined delay states of the SDR, wherein the delay state includes a range between 12.5 ps/° C. and −3.5 ps/° C., wherein the delay state is associated with a parameter of the SDR, and wherein the parameter includes any one or more of a receive frequency, transmit frequency or bandwidth; generating a calibrated signal based upon the determined delay state; and sending the calibrated signal to the SDR, wherein the calibrated signal causes the SDR to adjust its time and operate in a second state.
2. 2 . The method of claim 1 , further comprising: receiving another output signal from the SDR operating in the second state; and determining, based upon the received other output, another delay state of the SDR from the plurality of predetermined delay states of the SDR.
3. 3 . The method of claim 2 , further comprising: generating another calibrated signal based upon the other state; and transmitting the other calibration signal to the SDR for operating in a third state.
4. 4 . The method of claim 1 , wherein the predetermined delay states are obtained by: collecting, prior to the transmitting step, a plurality of signals output from the SDR; and characterizing the parameter for each of the collected signals.
5. 5 . The method of claim 1 , wherein the stimulus signal includes a radio frequency signal and a pulse per second (PPS) signal.
6. 6 . The method of claim 1 , wherein the stimulus signal includes a global navigation satellite system (GNSS) waveform.
7. 7 . The method of claim 1 , where the calibrated signal is a function of an operating temperature of the SDR.
8. 8 . The method of claim 1 , wherein the calibrated signal is a sub-nanosecond signal measured in picoseconds.
9. 9 . A system comprising: non-transitory memory including instructions stored thereon; and a processor operably coupled to the non-transitory memory, wherein the processor is configured to execute the instructions including: causing a transmission of a stimulus signal to a software defined radio (SDR) operating in a first state; causing a reception of an output signal from the SDR based upon the transmitted stimulus signal; determining, based upon the received output signal, a delay state of the SDR from a plurality of predetermined delay states of the SDR, wherein the delay state is associated with a parameter of the SDR, and wherein the delay state includes a range between 12.5 ps/° C. and −3.5 ps/° C.; and causing to generate a calibrated signal based upon the determined delay state.
10. 10 . The system of claim 9 , wherein the processor is further configured to execute the instructions of causing to send the calibrated signal to the SDR.
11. 11 . The system of claim 9 , further comprising: a signal generator and a clock/calibration module.
12. 12 . The system of claim 11 , wherein the processor, the signal generator and the clock/calibration module are housed in a single casing.
13. 13 . The system of claim 9 , wherein the parameter includes any one or more of a receive frequency, transmit frequency or bandwidth.
14. 14 . A system comprising a software defined radio (SDR), wherein the SDR is configured to execute a set of instructions including: sending, while in a first state, an output signal to a remote system, wherein the output signal indicates a delay state associated with a parameter of the SDR, wherein the delay state includes a range between 12.5 ps/° C. and −3.5 ps/° C.; receiving, from the remote system, a calibrated signal; and updating, based upon the calibrated signal, to a second state from the first state.
15. 15 . The system of claim 14 , further comprising a satellite encasing the SDR.
16. 16 . The system of claim 14 , wherein the system operates at a temperature ranging between −20° C. and 50° C.
17. 17 . The system of claim 16 , wherein an internal pressure of the system is about 10 −5 Torr.
18. 18 . The system of claim 14 , wherein the parameter includes any one or more of a receive frequency, transmit frequency or bandwidth.
19. 19 . The system of claim 14 , where the calibrated signal is a function of an operating temperature of the SDR.

Description

CROSS-REFERENCE TO RELATED APPLICATION This application claims priority to U.S. Provisional Application No. 63/420,866, filed Oct. 31, 2022, entitled “Methods and Systems for Controlling Timing Capability,” the content of which is incorporated by reference herein in its entirety. FIELD This application generally relates to systems and methods for improving waveform synthesis. More specifically, the systems and methods for improving waveform synthesis are employed in the field of Positioning, Navigation, and Timing (PNT) systems. BACKGROUND A satellite in orbit typically must maintain certain information about its state in orbit in order to functional properly. Systems that provide or use this type of information may be referred to as PNT systems. Positioning refers to the ability to determine a satellite's location in three dimensions relative to a selected frame of reference, e.g., an Earth-Centered, Earth-Fixed (ECEF) coordinate system. Navigation refers to the ability to employ positioning information to determine relationships between the position of multiple satellites or between positions of one satellite at various times. Timing refers to the ability to determine a satellite's time relative to a selected time reference. For example, this may be a clock offset between the satellite's local clock and Coordinated Universal Time (UTC). Timing may also include time transfer, which is the capability to transfer local knowledge of time from one location or system to another. PNT systems require a high degrees of synchronization accuracy. However, conventional PNT systems exhibit non-deterministic radio frequency (RF) characteristics causing fluctuations in synchronization analysis and normal routines. In additional, conventional PNT systems employing GPS are generally unencrypted and exhibit low power. GPS related satellite architectures are therefore more susceptible to disruption caused by jamming, spoofing or on-orbit attacks. What is desired in the art are architectures and techniques configured to generate signals with tightly controlled RF characteristics. What is also desired in the art are architectures and techniques that tightly control analog signal delays to a remote system. What is further desired in the art are architectures and techniques configured to completely characterize delays in digital signals received from a remote system. What is even further desired in the art are architectures and techniques offering GPS augmentation and/or replacement options in GPS-denied environments. SUMMARY The foregoing needs are met, to a great extent, by the disclosed systems, methods, and techniques described herein. One aspect of the patent application is directed to a method for waveform synthesis. The method may include a step of transmitting a stimulus (timing) signal to a software defined radio (SDR) operating in a first state. The method may also include a step of receiving, via the SDR, an output signal based upon the transmitted stimulus signal. The method may also include a step of determining, based upon the received output signal, a delay state of the SDR from a plurality of predetermined delay states of the SDR. The delay state may be associated with a parameter of the SDR. The parameter may include any one or more of a receive frequency, transmit frequency or bandwidth. The method may further include a step of generating a calibrated signal based upon the determined delay state. The method may even further include a step of sending the calibrated signal to the SDR to adjust a time. Another aspect of the application describes a system for waveform synthesis. The system includes a non-transitory memory including instructions stored thereon. The system also includes a processor operably coupled to the non-transitory memory configured to execute a set of the instructions. One of the instructions may include causing a transmission of a stimulus (timing) signal to a software defined radio (SDR) operating in a first state. Another one of the instructions may include causing a reception of an output signal from the SDR based upon the transmitted stimulus signal. Yet another one of the instructions may include determining, based upon the received output, a delay state of the SDR from a plurality of predetermined delay states of the SDR. The delay state may be associated with a parameter of the SDR. A further one of the instructions may include causing to generate a calibrated signal based upon the determined delay state. There has thus been outlined, rather broadly, certain embodiments of the application in order that the detailed description thereof herein may be better understood, and in order that the present contribution to the art may be better appreciated. There are, of course, additional embodiments of the application that will be described below and which will form the subject matter of the claims appended hereto. BRIEF DESCRIPTION OF THE DRAWINGS To facilitate a fuller understanding of the ap