FMCW Radar Communications Time Transfer Positioning
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Solution Overview
Problem
Current systems for combined radar and communications face challenges in providing simultaneous time transfer and position determination services without satellite-based positioning systems, and they suffer from interference issues when using the same RF spectrum across multiple platforms.
Innovation Solution
A combined radar/communications system utilizing a frequency-modulated continuous waveform (FMCW) that allows for simultaneous radar and communications operations, enabling time transfer and position determination using a common antenna and power source, and employs synchronization and demod/remod filtering to reduce interference between platforms.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If separate time transfer and position determination hardware is used for GPS outage operation, then time and position information can be determined during satellite system failures, but system complexity and cost increase significantly
Solution Approach 1:
The patent combines radar and communications functions into a single system that operates during GPS outages. The radar system transmits FMCW signals while simultaneously communicating time and position information to other platforms, eliminating the need for separate hardware and reducing overall system complexity while maintaining reliability during satellite system failures
Solution Approach 2:
The radar system is designed to perform multiple functions simultaneously: radar sensing, time transfer, and position determination. By encoding time and position data within the radar waveform itself, the system achieves GPS-independent navigation capabilities without requiring dedicated hardware for each function
2Productivity
If multiple radar platforms operate on the same RF spectrum, then spectrum efficiency improves, but interplatform interference increases
Solution Approach 1:
The patent implements synchronized periodic transmission where multiple radar platforms transmit FMCW signals in coordinated time slots. By synchronizing the radar chirps across platforms and using demod/remod filtering, the system allows simultaneous operation on the same RF spectrum while managing interference through structured periodic transmission patterns
Solution Approach 2:
The patent uses demod/remod filtering as an intermediary process to separate desired signals from interfering signals. The receiving platform demodulates the received FMCW signal to extract time and position information while filtering out interference from other platforms operating on the same spectrum, enabling coherent multi-platform operation
3Device complexity
If common antenna and power source are used for radar and communications, then system complexity and cost are reduced, but signal-to-noise ratio deteriorates
Solution Approach 1:
The patent segments the signal processing into distinct radar and communications channels that share the common antenna and power source. By using FMCW waveform segmentation where different portions of the waveform carry radar sensing information versus time/position communication data, the system maintains measurement precision while achieving hardware consolidation
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
Enables efficient time transfer and position determination services at lower signal-to-noise levels and reduces interplatform interference, allowing multiple radar systems to operate on the same RF spectrum without performance restrictions.
Implementation Method 1
a common radar/communications transmitter configured to transmit frequency-modulated continuous-wave signals
Implementation Method 2
transmit frequency-modulated continuous-wave signals representing packets of data
Implementation Method 3
frequency-modulated continuous-wave signals representing packets of data
Data Source
AI summary
A system and a method that enable time transfer and position determination services during operation of a combined radar/communications system. One aspect of the method is broadcasting a signal that any system receiving it can use to synchronize system clocks to the set of master clocks among a selected subset of transmitting platforms. This broadcast signal can occur during both radar and communications operations. In addition, with three or more mobile or fixed platforms broadcasting the signal, any one receiving the signal can also derive position information. The time transfer and position determination service can operate at the same time as operation of both radar and communications functions. The broadcast information is derived from internal time and position information as determined by the individual transmitting platforms. A small set of such platforms are configured to broadcast signals that transfer both accurate time and accurate position to all other platforms within radiofrequency (RF) range.