NASA’s Technology Transfer Program solicits inquiries from companies interested in obtaining license rights to commercialize, manufacture and market the following technology. License rights may be issued on an exclusive or nonexclusive basis and may include specific fields of use. NASA provides no funding in conjunction with these potential licenses.

THE TECHNOLOGY:

NASA pioneered Navigation Doppler Lidar (NDL) for precision navigation and executing well-controlled landings on surfaces like the moon. The lidar sensor utilizes Frequency Modulated Continuous Wave (FMCW) technique to determine the distance to the target and the velocity between the sensor and target. Specifically, homodone sensors obtain the changes in signal frequency between the received and reference frequencies for calculating both speed and distance. However, homodyne detection cannot provide any phase information. This is a problem because the current sensor cannot determine the sign (+/-) of the signal frequencies, resulting in false measurements of range and velocity. NASA has developed an operational prototype (TRL 6) of the method and algorithm that works with the receiver to correct the problem. Using a three-section waveform and an algorithm to resolve ambiguities in sign when the signal is compromised, the algorithm analyzes historical phase information to interpret the sign of the remaining frequencies and recover the phase information that contains valuable measurement information.

The NDL uses homodyne detection to obtain changes in signal frequency caused by a target of interest. Frequency associated with each segment of the modulated waveform collected by the instrument is positive or negative, depending on the relative range and direction of motion between the NDL and the target. Homodyne detection offers a direct measurement of signal frequency changes however only the absolute values of the frequencies are measured, therefore additional information is necessary to determine positive or negative sign of the detected frequencies. The three segmented waveform, as opposed to conventional two-segmented ones, allows for resolving the frequency sign ambiguity. In a practical system, there are times when one or more of the three frequencies are not available during a measurement. For these cases, knowledge of the relative positions of the frequency sideband components is used to predict direction of the Doppler shift and sign, and thus make correct range and velocity measurements. This algorithm provides estimates to the sign of the intermediate frequencies. The instrument operates continuously in real time, producing independent range and velocity measurements by each line of sight used to take the measurement. In case of loss of one of the three frequencies, past measurements of range and velocity are used by the algorithm to provide estimates of the expected new range and velocity measurement. These estimates are obtained by applying an estimation filter to past measurements. These estimates are used during signal loss to reduce uncertainty in the sign of the frequencies measured once signals are re-established, and never to replace value of a measurement.

To express interest in this opportunity, please submit a license application through NASA’s Automated Technology Licensing Application System (ATLAS) by visiting https://technology.nasa.gov/patent/LAR-TOPS-351

If you have any questions, please e-mail NASA’s Technology Transfer Program at [email protected] with the title of this Technology Transfer Opportunity as listed in this SAM.gov notice and your preferred contact information. For more information about licensing other NASA-developed technologies, please visit the NASA Technology Transfer Portal at https://technology.nasa.gov/

These responses are provided to members of NASA’s Technology Transfer Program for the purpose of promoting public awareness of NASA-developed technology products, and conducting preliminary market research to determine public interest in and potential for future licensing opportunities. No follow-on procurement is expected to result from responses to this Notice.