TTNT Datalink Ranging for UCAV Precision Rendezvous

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Solution Overview

Problem

Current systems for relative navigation in unmanned combat air vehicles (UCAVs) during aerial refueling lack precise, low-latency three-dimensional positioning capabilities, especially when GPS is denied, and require a low-observable communications datalink with high integrity and reliability.

Innovation Solution

A relative navigation system utilizing a Tactical Targeting Network Technology (TTNT) datalink for two-way time transfer ranging and an antenna array on the lead aircraft for azimuth and elevation determination, providing high-accuracy positioning and serving as a backup for GPS navigation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If TACAN is used for rendezvous navigation, then navigation capability is provided, but low-observable requirement is not met

Engineering Contradiction:

Improvenavigation capabilityVSAvoidobservability

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent replaces the TACAN radio navigation system with a GPS-based navigation system. This substitution eliminates the need for TACAN ground stations and associated radar emissions, providing both navigation capability and low-observable characteristics through satellite-based positioning.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent changes the fundamental operating parameters of the navigation system by transitioning from TACAN's ground-based radio wave propagation to GPS's satellite-based signal transmission. This parameter change enables simultaneous achievement of navigation reliability and low observability.

Inventive Principle:

Principle #35Parameter changes

2Measurement precision

If visual navigation is used for fine navigation, then precision is improved, but automation is reduced

Engineering Contradiction:

Improvefine navigation precisionVSAvoidautomated control

Core Design Contradiction:

Measurement precisionVSExtent of automation

Solution Approach 1:

The patent implements automated fine navigation through continuous feedback from GPS receivers on both tanker and follower aircraft. The system constantly monitors relative position data and automatically adjusts navigation commands, eliminating the need for manual visual navigation while maintaining high precision.

Inventive Principle:

Principle #23Feedback

Solution Approach 2:

The navigation system performs self-service by automatically computing relative position and guiding the follower aircraft using GPS data without requiring pilot intervention. The boom operator retains control authority but the navigation function is fully automated.

Inventive Principle:

Principle #25Self-service

3Device complexity

If standalone GPS positioning is used, then system complexity is reduced, but accuracy is insufficient for capture phase

Engineering Contradiction:

Improvenavigation system complexityVSAvoidrelative positioning accuracy

Core Design Contradiction:

Device complexityVSMeasurement precision

Solution Approach 1:

The patent merges the GPS receivers from both the tanker and follower aircraft into a combined relative navigation system. By processing GPS data from both platforms together and adding inertial navigation system (INS) data, the system achieves high-accuracy relative positioning while keeping individual aircraft systems relatively simple.

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The GPS receivers serve multiple functions: standalone positioning for coarse navigation, relative positioning for precision approach, and integrity monitoring. The same hardware infrastructure supports multiple operational phases from rendezvous through capture and refueling.

Inventive Principle:

Principle #6Universality (Multi-functionality)

4Measurement precision

If high data rate communication is implemented, then navigation solution quality is improved, but datalink bandwidth requirement increases

Engineering Contradiction:

Improvereal-time navigation solution accuracyVSAvoiddata transmission rate

Core Design Contradiction:

Measurement precisionVSQuantity of substance

Solution Approach 1:

The patent transmits only the essential GPS and INS data elements required for navigation solution computation rather than complete raw data streams. This partial action approach provides sufficient navigation accuracy while constraining data transmission rates to manageable levels.

Inventive Principle:

Principle #16Partial or excessive action

Data Source

PatentUS7418343B1Relative navigation for precision rendezvous and station keeping using datalink signals

Publication Date: 2008.08.26 ROCKWELL COLLINS INC

AI summary

A follower aircraft is guided to a lead aircraft using a datalink that determines range between the two. The lead aircraft has an antenna array and processing system for determining azimuth/elevation of the follower aircraft. The lead aircraft transmits a ranging message to the follower aircraft and stores a lead aircraft time of transmit (TOT) time. The ranging message is received at the follower aircraft and a follower aircraft time of reception (TOR) time is stored. A second ranging message is transmitted from the follower aircraft to the lead aircraft and a follower aircraft TOT time is stored. The second ranging message is received at the lead aircraft and a lead aircraft TOR is stored. A message is sent from the follower aircraft when follower aircraft TOT and TOR. The range and time offset is determined by the lead aircraft using follower aircraft TOT/TOR and stored lead aircraft TOT/TOR.