is it possible to build an INS system for car navigation? with out the aid of GPS?

Question

im currently having my thesis w/c is about navigation. how can i create a car navigation system that would not rely on GPS?

Answer 1

Both ring gyros and accelerometers have drift. The error grows exponentially. After only a short while (think in seconds or at best minutes, not hours) your position estimate is useless.

You need some other source of position information to correct the INS. It doesn't have to be extremely accurate, but it does need to be reliable. A Kalman filter, then, can use the high resolution INS data along with the external position data to provide a high accuracy position estimate.

So, you can do it without GPS, but not without _something_ as a position measurement to restrict the error buildup of the INS

Answer 2

This is an excellent question, I don't believe I've ever seen it on Answers before now. The answer depends on what YOU want out of your nav system. A Garmin or other handheld unit is fantastic if you plan on using it in other locations than just your vehicle. If you hike, ride with others, etc then it can be a very useful tool. If it's going to stay in one vehicle 99% of the time the scales tip a bit...for starters it's a shining star for car theft. They're easy to steal and easy to sell. In regards to features the $500 Garmin is not going to come anywhere close to a built-in OEM unit. The OEM unit was designed by a car company for a car...often times it's specific to your model. It communicates information about location, speed, traffic, etc to your vehicle, it interacts with bluetooth devices, etc. It also aids in making your vehicle control systems more accessible/customizable....the radio, any special monitors (tires, etc), HVAC controls, etc are all incorporated into 1 unit. The OEM systems can typically be set to notify you of major traffic, construction, etc over the stereo system...muting any music you have playing temporarily so you can hear the directions. For my money the OEM navigation is the way to go. My 08 Suburban has factory nav and it's wonderful. My old Suburban had a Garmin I bought at Best Buy (my wife now uses it in her car, it's only 6 months old or so)....the OEM is light years better than the Garmin, reacts faster, more accurate, and more options. Again...if you want to move the GPS with you, get a Garmin. If you're on the highway/travel a lot then go for the OEM nav system. Keep in mind each car maker offers a different style/quality of built-in nav. Do your research prior to making the final decision. Many of the newer makes don't even require the traditional DVD loading system (you have to load maps, etc), they download the information necessary without you blinking an eye or lifting a finger. Hope this helps!

Answer 3

Inertial Nav Systems were the fore runner of Sat. Nav. Developed out of need for an accurate totally passive system for the delivery of nukes. The requirement was for no dependence on any external input ie radio signals, magnetism or radar. They rely on a stable gyro platform with less than 0.05 deg/hour drift, and very sensitive accelerometers with an accurate starting and end point reference. The accelerometers had a sensitivity such that placed on the end of 200ft (non flexing) pole, they would detect a lift of 1 inch at the other end. INS also had the option in manned vehicles to update current position from visual observations.
The Vulcan bomber used INS and I think the early cruise missiles. Accuracy was pretty good but needed a lot of regular tuning. I have spent many hours tweaking gyro drift to get within tolerance. A feasable option for cars, but I cannot see the average driver setting it up for a trip to Grannies assuming you could find the grid reference for Granny.

You could forego some of the accuracy by stabilising the gyro platform using a compass type servo loop.

If you did not need to be totally passive then any identifiable radio source will do. FM stations in the UK give out an identifiable signal that car radios decode and display station and frequency, which in turn could be used to identify its ground position. Triangulation is then possible with direction sensing aerials. This would be an alternative to sattellites but not really inertia based.

Best of luck.

Answer 4

I suppose it would be possible to make an INS system for an automobile, but it would take up most of the trunk ☺
Plus, INS systems usually have a certain amount of 'drift' inherent in them and have to be corrected with known navigational 'fixes' before the drift becomes unacceptable.

Doug

Answer 5

It surely is possible - the army had INS - gyroscopes in vehicles - to lay in field artillery long before GPS came about. The system was fairly large - like the one poster said it will fill the trunk - I wouldn't know the first thing about how to design / build it - but you only asked if it was possible.

Answer 6

Submarines do not have regular access to satellite info, so must rely on inertial systems. Most navies use Ring Laser Gyro system. Sperry marine, a division of Northrop-Grumman is the main manufacturer.

Answer 7

you could use gyro's (not the food the other kind) and accelerometers and load software in denoting your starting position. You would have to build, and program the system yourself. Overall just get a GPS cause they are only like $150 on Amazon.com for Magellan Roadmates that are pretty reliable.

Answer 8

You could use a theadalite, astronomical observations, bearings and distances, predesignated reference points. All would be a lot more impractical than gps but fessable.

Answer 9

I don't know if it's feasible, but it is possible. You could use cell phone towers to triangulate your location. This would obviously have limitations, but you didn't say one that worked all the time.