NASA - Local Positioning System

The goal of this project is to create a relatively cheap and easy to set up method of tracking people, vehicles, and equipment in real time in an area where GPS is unavailible (i.e. Mars).

=Problem Definition=

Background
Current Global Postitioning Systems(GPS) require the use of satellites in order to determine a location. On another planet like Mars they would be expensive to ship and difficult to repair or move to a different location. By using a series of balloons tethered around a specified point, it is possible to create a system that would function at a much cheaper cost and be easier to set-up and use than satellites.

Deliverables
The Local Positioning System must act as an easy to set up replacement for GPS systems mounted on a series of tethered balloons. It must cost less than the price of shipping a satellite to Mars and update a users location in "real-time"

Functional Requirements

 * User Interface
 * The system shall take no more than 3 hours for 3 people to set up and launch
 * All set up activity shall take place no more than 250 m from a defined central point.
 * Postitioning Requirements
 * Position information shall be displayed to a user at the defined central point or to a mobile user.
 * The system shall determine the positions of one mobile unit relative to a defined central point.
 * Positions shall be determined with an accuracy of +/- 4 m in any direction.
 * shall be determined and displayed within 10s of a mobile unit occupying that position.
 * Position measurements should be time stamped and recorded.
 * The system shall be capable of determining positions of mobile units anywhere within a 7 km radius of the reference point.
 * The system shall operate continuously for at least 8 hours.

Flight Requirements

 * Critical subsystems shall be designed to fly on moored (tethered) balloons.
 * At least one balloon shall be launched as a critical part of a demonstration of the system.

Environmental Requirements

 * The system is expected to have full operational capabilities in environments with ambient temperatures of -20°C to 40°C and winds of up to 9 m/s and no precipitation.

Regulatory Requirements

 * FAA Requirements
 * 14 CFR 101.13
 * 14 CFR 101.15
 * 14 CFR 101.17
 * 14 CFR 101.19


 * FCC Requirements
 * Communications devices must operate in amateur radio or unlicensed frequency bands, and comply with all regulations that apply to the selected bands. See FCC frequency allocations (3) and relevant regulations.
 * All components must comply with FCC regulations at all times.

Cost Requirements

 * Cost of a theoretical final product shall not exceed the cost of a GPS satellite launch.
 * Cost to produce the prototype shall not exceed $10,000.

=Design Considerations=

Theory
Fundamentally, the location of an object can be determined by measuring its distance or angles from three or more known references. The more references used in the calculation of the position will increase the accuracy of the calculation. By measuring the time it takes for a signal of an unknown origin to travel to a receiver with a known location, it is possible to determine how far a way the signal originated from. Using the distances from known references is called Multilateration. Our current design is to use three tethered balloons who's locations are known in order to provide the known references, and use the time it takes for a radio signal to reach each of the three balloons to find the location of a mobile object.

=Project Learning=

=Final Design=

=Validation=

=Team Members=

=Additional Documentation=


 * | Project Schedule


 * | Project Value Proposition


 * | Snapshot 1


 * | Client Interview