How To Not Get Lost

[delnorter]

Great advice in the posts. Steve is so right about relying on your instruments. Here in the pacific northwest weather can change for the worse very quickly and instruments are your friend. 

I do have a interesting story of the instruments going astray.

I managed as well as did the actual work of an aerial mapping, surveying and high altitude photography company for many years. Using small Cessnas (182 and push pull turbo 206) and Robinson helicopters required the pilots to really trust their instruments. 

We also performed land surveys with conventional instruments like theodolites and chains, early lasers, later total stations with infra red and the such. We eventually bought and used some of the first Trimble Navigation GPS units here in the northwest.

We were performing a large cadastral retracement survey of public / private boundaries for the federal government over two townships of land with many ownerships. Because of the rugged and remote lands, we used a combination of technology. All of the above conventional equipment was used along with aerial photos and the "relatively new GPS units".

We used the tripod mounted GPS units primarily for establishing control points on the mountain tops, from which we then utilized the other instruments for ground traverses. Well into the project, amazed by the benefit of the GPS units and their accuracy, which we tested, all hell broke out with the data.

In these kinds of surveys, along with the GPS control points, a lot of data is collected initially about existing prior survey evidence, often for days at a time, and then is processed back in the office for further investigation and action in the field.

Well, after one such period of data collection from the GPS units, absolute chaos ensued with the survey control data as well as the the other traverses from those control points. Survey results from this period was miles off from previous data collected. Impossible to be as such.

I'm telling you, this was on par with losing a survey field book in the old days, which was a cardinal sin. The entire job is at a standstill.

As I recall our first call to Trimble (the GPS maker) was of no help and caused a great concern on their part as well. They got on the horn and called us back later with the explanation.

The first gulf war had just begun and the military had "dithered" the signals coming from the constellation of satellites utilized by our GPS units. They were preventing any enemy from using these signals for hostile action over in the Gulf or here at home with missiles or airplanes. We eventually received, from the military, an equation / formula for untangling the survey data and all turned out well.

There was very little use of GPS by the public back then relative to the widespread use today. If the signals were again "dithered" by the government, in this day and age, oh boy,  just imagine.

Mike

 

 

[strick]

On March 22, 2017 at 9:40 PM, whitebutler said:

I learned to use the stars and the sun. My father was a sailor and insisted I learned how to get home. I encourage others to learn also. 

The first sailors used star charts and those haven't changed is thousands of years. Know the stars and change yours.

Cheers

John

Probably the most heroic survival story ever is the story of Ernest Shackleton and his crew on the  Endurance. When they became stranded on an ice pack in the Antarctic he and 4 other men set off in a 23 foot boat 800 miles to a whaling station. They navigated by the stars and sun to get there.  

strick

 

[mntnflyr4fun]

How do you teach a tipi to use a GPS?

As my father used to tell me as we looked for our vehicle after a day of hunting..........Indian not lost, Tipi lost....

[tvanwho]