Why Is My GPS Less Accurate In The City?
Multi-Path Interference Results In GPS Acquisition Challenges
Most people are now familiar with using GPS navigational equipment or tracking devices, using the satellite tracking tools for anything from turn-by-turn directions to fleet management. Over the past 15 years GPS has worked brilliantly to help everyday motorists quickly access directional data in both real-time and historical formats, and although the technology offers countless benefits and advantages for both consumers and businesses, the technology is not perfect.
No matter what a manufacturer or reseller of GPS equipment tells a person, all GPS units still adhere to the same basic principles. These principles include things such as an inability to acquire GPS signals if the receiver is surrounded or encased in something that is metal or concrete. Of course, GPS navigational system users rarely have issues regarding device placement because the unit is typically installed to the front windshield of the vehicle where optimum line of sight to the sky is present. However, GPS tracking system users typically require a covert placement option, making antenna design and functionality essential to effective and accurate GPS data recording. However, even if a GPS navigation system or GPS tracking unit is placed in a premium location there are still occasions when inaccuracies in data can occur.
How Tall Buildings Can Create GPS Inaccuracies
People living in a very urban area with tall buildings all around may often times receive GPS data that is slightly less accurate than in areas where less high rising buildings are present. A very common problem with GPS devices being used in "urban canyon" areas such as New York City and Chicago is phenomenon called multi-path interference. Multi-path interference is caused when the location-based device does not have a clear shot or line of sight at the sky. In areas where there are many tall buildings, the source signal of the GPS device can split into more than one signal, causing erroneous readings. When a engineer of vehicle tracking systems for Chicago-based LandAirSea Systems was asked about this unique phenomenon he stated, "Urban canyons do pose a challenge [to GPS acquisition and highly accurate data gathering], and when dealing with this situation, placement of the device is critical. If [the user] mounts a unit such as the SilverCloud upside down or underneath the car, the unit will not work very well in an urban canyon. However, placing the device on the dash should produce usable results that are sufficient. It's not a perfect world with this technology. Some people want 5ft accuracy in downtown Manhattan with a unit under the car, and the reality is that probably is not going happen."
One of the biggest complaints people have about GPS devices is that the technology sometimes does not work "as advertised" in highly populated metropolitan regions where urban canyon environments are present. They will often state that cellular reception in the area of use is strong, and the placement of the personal tracking system is in what would be categorized as an ideal location, but still inaccuracies in GPS still pop-up on occasions. For those who have experienced this type of scenario, hopefully this article has helped bring some clarification to what might be happening.
Tracking System Direct (TSD) recommends that anyone with questions regarding car tracking surveillance devices such as the GPS Tracking Key or SilverCloud tracker contact one of the GPS specialists at TSD for assistance. GPS professionals are standing by 7 days a week to provide answers to all of your GPS questions!