US 12,345,795 B2
Ground map monitor for map-based, vision navigation systems
Vibhor L. Bageshwar, Rosemount, MN (US); and Brian Schipper, Maple Grove, MN (US)
Assigned to Honeywell International Inc., Charlotte, NC (US)
Filed by Honeywell International Inc., Charlotte, NC (US)
Filed on Jan. 14, 2022, as Appl. No. 17/576,711.
Prior Publication US 2023/0228860 A1, Jul. 20, 2023
Int. Cl. G01S 13/00 (2006.01); G01S 7/00 (2006.01); G01S 13/89 (2006.01); G01S 13/91 (2006.01)
CPC G01S 13/003 (2013.01) [G01S 7/006 (2013.01); G01S 13/89 (2013.01); G01S 13/91 (2013.01)] 12 Claims
OG exemplary drawing
 
1. A method comprising:
providing a ground map monitor system that monitors for changes to ground/terrain features shown in a navigation map, the ground map monitor system including at least one processor that performs a process comprising:
obtaining positions, from a database, for a plurality of communication nodes in a communications network;
selecting one or more transmission nodes and one or more reception nodes from the plurality of communication nodes;
measuring bistatic signals between the one or more transmission nodes and the one or more reception nodes to determine nominal signal performance characteristics for the bistatic signals, including one or more of reflected signal time delays, signal frequency shifts, or signal power levels;
monitoring the bistatic signals for changes to the nominal signal performance characteristics;
using a discriminator between the nominal signal performance characteristics and a current performance level of the bistatic signals, and comparing the discriminator against a performance threshold, to determine whether current signal performance characteristics have varied from their nominal levels, wherein the performance threshold is user selected for the one or more of reflected signal time delays, signal frequency shifts, or signal power levels;
ignoring instantaneous changes in the nominal signal performance characteristics, wherein a time period that a change is classified as instantaneous is a user selected time threshold; and
broadcasting an alert signal that a section of the navigation map is not useable for navigation of a vehicle if changes in the current performance level of the bistatic signals exceeds the performance threshold and the time threshold.