What You Need to Know about Location Marketing Tech - #1: GPS

Engaging customers based on where they are is useful and valuable. This post is the first in a series that will dig into the location technologies now available. We will start with GPS since it's the granddaddy of them all.

Everybody Knows GPS, Few Understand it.

GPS, or Global Positioning System, is a satellite-based system. Each satellite has an atomic clock kept in sync with every other satellite's clock. There are a bunch of satellites flying around up there.

Line of Sight

To get a position fix, you need to "see" at least four satellites. Three will figure out where you are (2D). The fourth locks in your altitude (3D). Your GPS receiver or phone then calculates your position.

Altitude fixes are notoriously inaccurate. 

Theory vs Reality

In theory, your position can be accurate within 1.1132 millimeters. For you metric-phobes that's about this much "-"

In reality, you can't.

It isn't because the system can't provide that degree of accuracy. It's because our phones can't calculate our position to within 8 accurate decimal places.

I say "accurate" decimal places because the last one is always an approximation.

More on Accuracy

The world is a big place. One degree of longitude (east-west) at the equator is 111.32 km or about 70 miles. One degree of Latitude (north/south) is about the same, 111.2 km (69 miles).

To complicate things,

The distance between longitudes changes the closer you get to either pole. Eventually, they all meet at the poles, so the distance between them is 0.

Fun, eh?

Complicate it just a little more

Our planet is not a sphere. It's an oblate spheroid. That's math-speak for a squished ball. We pretend it's a sphere to make the math simpler.

Does anyone else find it funny that somebody thinks this is simple?

Putting it in Context

I based the following on a table found on Wikipedia.

• 0 decimal places: Somewhere within a large place like a country.
• 1 decimal place: Somewhere within a large city or district
• 2 decimal places: Somewhere within a town or village
• 3 decimal places: Somewhere within a neighborhood
• 4 decimal places: Somewhere within a land parcel. This is where it starts becoming useful. Your position is accurate within 11.132 meters (36.5 feet). This is the accuracy most phones can provide. Some actually do a little better because of a fifth approximate decimal place 
• 5 decimal places: Within a few feet. Fantastic for most applications, but rarely achieved. Few phones can manage it.

Uses for GPS in Location Marketing

There aren't all that many actually. It can tell me where your nearest store is. Right now, I'm working with a coupon distribution company. The idea is to push coupons when you are within a few miles of an outlet.

All the accuracy numbers quoted here are based on being outdoors. You actually have to be in the line of sight to the satellites. That's tough to do indoors.

Most stores are indoors (duh!).

Yes, there are schemes to adjust. Most use Wi-Fi boxes to approximate position. But the best indoor accuracy I have ever experienced is 15 meters (~50 feet). That's pretty useless for location-based marketing. Outdoors I have achieved 2.7 meters.

The Issues Don't Stop There

GPS doesn't do anything alone. Sure the phone will calculate position, then what? You need an app to do the heavy lifting. That's a major issue. People just don't keep apps installed. Get over it.

GPS is best suited for outdoor things.

It's great for tracking vehicles and such. Many companies incorporate it into Mobile Device Mangement (MDM).

I set up one app that maps and color-codes existing customers and prospective customers for a B2B outfit.

One company I know uses it to track, and dispatch technicians. That's not marketing  per se , but it does improve customer satisfaction.

Another uses it to track shipping containers in real time.

A golf course uses it to provide tips on how to play each hole.

I used a version of it, Geocaching, to make a company scavenger hunt. (Hmmm, possible gamification layer?)

I used another version, Geofencing, to notify my wife when I got off the freeway. My phone would send a text:

"Just got off freeway . Be home in 5. Pls make martini ."

She wasn't impressed with my coding ability. 

She kept muttering something about Stepford wives.

Go figure!

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