US 5,177,685 · Granted 1993-01-05
The MIT Patent That Invented Turn-by-Turn Voice Navigation
Imagine a computer in your car that knows exactly where you are on a map, figures out the best route to get where you're going, and then tells you out loud when to turn left or right — all in real time. This patent describes the core technology behind modern GPS navigation systems that talk to you while you drive.
The plain-English version
What it protects
The claim covers a system that combines a map database, route-finding software, vehicle location tracking (from motion sensors), and speech generation to deliver real-time spoken driving instructions. What's protected here is the integration of these components: the computer determining your position as you move, calculating the optimal route, generating natural language instructions dynamically, and converting them to spoken voice — the whole pipeline working together to guide a driver without paper or looking away from the road.
Why it matters
This patent captures the foundational architecture of modern automotive GPS systems. Filed in 1990 and granted in 1993, it arrived at the moment when computing power and vehicle sensors were becoming affordable enough to make in-car navigation practical. The patent's approach — combining real-time location tracking, route algorithms, and synthesized speech — became the blueprint that companies like Garmin, TomTom, and later smartphone navigation apps followed. It represents the shift from pull-over-and-check-a-map to continuous, hands-free guidance.
Real-world use
Every time your phone or car's built-in system announces 'Turn right in 500 feet' while you drive, you're experiencing the core innovation this patent protects — location awareness plus instant voice instructions working in concert.
Original USPTO abstract
An automobile navigation system which provides spoken instructions to the driver of an automobile to guide the driver along a route is disclosed. The heart of the system is a computing apparatus comprising a map database, route finding algorithms, a vehicle location system, discourse generating programs, and speech generating programs. Driver input means allows the driver to enter information such as a desired destination. The route finding algorithms in the computer apparatus calculate a route to the destination. The vehicle location system accepts input from a position sensor which measures automobile movement (magnitude and direction) continuously, and using this data in conjunction with the map database, determines the position of the automobile. Based on the current position of the automobile and the route, the discourse generating programs compose driving instructions and other messages according to a discourse model in real time as they are needed. The instructions and messages are sent to voice generating apparatus which conveys them to the driver.
Patent details
- Publication number
- US 5,177,685
- Filing date
- 1990-08-09
- Grant date
- 1993-01-05
- Assignee
- Massachusetts Institute Of Technology
- Inventor(s)
- DAVIS; JAMES R., SCHMANDT; CHRISTOPHER M.
- CPC class
- B60R16/0373
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