**DroneCam Winds Down After 8056 Hours**

On June 6, 2013, DroneCam was shut down to allow some home remodeling. The work has been going on for three weeks now, and the lapse in coverage would certainly upset the statistics bearing on any conclusions I could make. Therefore, let's see what conclusions can be drawn from the data that was collected in the 96,670 30-second observations amounting to a span of nearly one year.

Assumptions

Since the habits of drone craft are not known, we must assume that all locations have an equal chance of visitation, so we can then use laws of probability based on a Gaussian distribution. We don't know if their range is the California Diamond, the USA, or the whole world. The California Diamond has vertices at Big Basin, Campbell, NASA/Ames, and Santa Cruz comprising 1365 square kilometers. The Continental USA comprises 9.37 million square km, and the Earth is 3.6x10^{8} sq km. I assume DroneCam had a good view of 1 sq km. Let the area under discussion be designated A.

We also don't know how long they dwell over any one site. Many reported sightings lasted several minutes. Due to my use of 15X time lapse photography I felt that 30 seconds was the shortest visitation I would be able to reliably detect. Let this dwell time be designated t. There are (24*3600)/t = 2880 observation opportunities per day per site or (8056*3600)/t = 96,670 observations for DroneCam.

We don't know how many Drones are visiting, but we can account for varying numbers in the math. Let the number of Drones visiting Earth be designated Q.

By the time the chances P_{N} of observing an event reach 50% even an unlucky sort like me would succeed after a few days of observing. We need to compute the required number of observations N when P_{N} = 0.5.

Observation

In short, no Drone was seen. Actually no UFO of any standard description was seen. I would like to re-compute these findings with an educated guess for Q, even if it includes non-Drone craft.

Conclusion

The probability of looking up in the sky for one 30-sec observation and seeing a Drone may be computed as P_{1} = Q/A. If N observations are required the probability is P_{N} = P_{1}(1-P_{1})^{N-1}. Solving for N we get N = 1+ln(P_{N}A/Q)/ln(1-Q/A).

I used a spreadsheet to solve for N given A, Q=1, and P_{N}=0.5. Negative results were shrugged at.

Area under Discussion Area sq km N number of observations

California Diamond 1365 8,905

Continental USA 9.37 E6 143,000,000

Planet Earth 3.60 E8 6,843,000,000

DroneCamâ??s 96,670 observations were more than enough to spot a single Drone flitting around the California Diamond. In fact, using â??what-ifâ? analysis, DroneCamâ??s observations should have been enough to confirm 837 Drones buzzing the USA, enough to suspect 32140 Drones swarming planet Earth.

Of course the assumptions were drawn pretty broadly, but this analysis may be used to establish an upper bound on the number of 'visitors' in the air, just as a sighting would have established a lower bound. May you have better luck than I.

~algae