Astro-Location (RFID Waypoint)
| RFID Waypoint | RFID Interrogator | Portable Array |
The
astronaut will be given an allotment of tiny RFIDs for bread crumbs to
be placed every 20 meters. These are not the only RFID items that
the astronaut will have at his or her disposal. They will be also
given an RFID Waypoint (Range up to 100 M given 500 W Burst when
astronaut is in distress)
The Lunar Astro-Track RFID waypoint is not a tiny device, but arguably it should not be. It is an American flag, as seen in many NASA lunar photos, with two RF components located near the top: an RFID device to assist in astro-location and passive RF repeater to assist astronaut / lunar lander link. Situating the small RF components and antennas at the top of the flag allow for better line of site. Also, in the event of a communications link failure, without a visible waypoint, finding the way back to the lunar lander would be difficult if not impossible. The RFID Waypoint flags are not very heavy and each astronaut should be able to carry at least five especially given that moon's gravity is one-sixth of earth's.
The Lunar Astro-Track RFID waypoint is not a tiny device, but arguably it should not be. It is an American flag, as seen in many NASA lunar photos, with two RF components located near the top: an RFID device to assist in astro-location and passive RF repeater to assist astronaut / lunar lander link. Situating the small RF components and antennas at the top of the flag allow for better line of site. Also, in the event of a communications link failure, without a visible waypoint, finding the way back to the lunar lander would be difficult if not impossible. The RFID Waypoint flags are not very heavy and each astronaut should be able to carry at least five especially given that moon's gravity is one-sixth of earth's.
The RFID return modulation is a direct sequence spread spectrum
signal that does not repeat in a given burst. Each waypoint is
given a unique spreading code (similar to gold-code) to distinguish the
different waypoints from one another.
The RFID time-delay is defined as the time between the incident 'power up' tone hitting the RFID and the subsequent response being transmitted. Prior to mission, each RFID Waypoint's time-delay is measured and stored in the interrogator's RFID lookup table.
The RFID time-delay is defined as the time between the incident 'power up' tone hitting the RFID and the subsequent response being transmitted. Prior to mission, each RFID Waypoint's time-delay is measured and stored in the interrogator's RFID lookup table.
Why not use only tiny 'bread crumbs'?
The lunar surface is not a flat surface and there is approximately
three inches of dust in most locations. Placing small devices
on the lunar surface does not provide an ideal propagation environment.