{"id":7054,"date":"2020-08-12T10:00:23","date_gmt":"2020-08-12T04:30:23","guid":{"rendered":"https:\/\/gtm360.com\/blog\/?p=7054"},"modified":"2022-03-31T13:34:07","modified_gmt":"2022-03-31T08:04:07","slug":"how-does-turn-by-turn-navigation-work","status":"publish","type":"post","link":"https:\/\/gtm360.com\/blog\/2020\/08\/12\/how-does-turn-by-turn-navigation-work\/","title":{"rendered":"How Does Turn By Turn Navigation Work?"},"content":{"rendered":"

A turn-by-turn navigation system<\/em><\/strong> is a combination of hardware and software that provides an automobile driver with one or more motorable routes between Point A and Point B on the surface of the earth. Sold as a dedicated satnav system or as an integral part of a smartphone, it comprises the following building blocks:<\/p>\n

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  1. GPS<\/strong>. More precisely, GPS Receiver. GPS looks up a combination of four geostationary satellites and tells the “LatLong”<\/a> i.e. latitude and longitude of the driver’s location on the surface of earth. The GPS system is owned by Department of Defence, USA. (According to some accounts<\/a>, GPS also reports altitude but it’s supposed to highly inaccurate. We can ignore that since there’s no flying involved in the present context!)<\/li>\n
  2. \"\"<\/a>Map<\/strong>. It shows roads, buildings, water bodies, bridges, tunnels and other attributes of the terrain. Despite asking around, I haven’t been able to figure out what some attributes stand for, like the one shown on the exhibit in the right. High end maps also contain information regarding speed radars, gas stations, and rest areas on the way.<\/li>\n
  3. Algorithm<\/strong>. This is the software program that computes the route from starting point to the ending point, projects it on the map, gives audio cues to the driver as s\/he reaches every turn, and tells him or her whether to turn left, turn right or go straight. Ergo the expression “turn-by-turn navigation”. Starting point is where the GPS is situated. Ending point is the destination that’s manually entered by the driver at the start of the journey. The algorithm works by finding all available pathways and their “quantity” and “quality”. “Quantity” is a fairly straight forward geometrical calculation based on interconnection of motorable roads, bridges over waterbodies on the way, tunnels through mountains, and so on. Quality takes into account speed limits, traffic disruptions caused by accidents, lane closures, and other parameters that are obtained from other smartphones or drivers on the route via Mobile Internet or dedicated FM frequencies respectively, as described in How Does Google Maps Know About Traffic Conditions In Realtime?<\/a> Since there could be multiple routes between any two points, the algorithm computes and displays all available routes, and either lets the driver select one manually, or computes the “best route” based on fastest route, route with the least toll, and other “constraints” specified by the driver.<\/li>\n<\/ol>\n

    When these three components work together, the driver gets a motorable route between point A and point B.<\/p>\n

    \"\"<\/a><\/p>\n

    People colloquially refer to turn-by-turn navigation as just “GPS” (or “Map” or “SatNav”). Which one in specific depends on the predominant brand involved e.g. Garmin GPS (or Google Maps or TomTom SatNav).<\/p>\n

    This tends to convey the impression that it comprises just one of the three components.\u00a0 That’s not true. Turn-by-turn navigation is a combination of all three building blocks.<\/p>\n

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    \"\"<\/a>IIT Bombay recently launched a chip called Dhruva<\/strong><\/em>. Please see exhibit on the right for details.<\/p>\n

    The article says Dhruva can find locations and<\/em> routes.<\/p>\n

    If Dhruva has GPS, it can obviously find locations.<\/p>\n

    But if Dhruva can also find routes, then it must be having embedded maps and algorithms to compute the “quantity” and “quality” of pathways.\u00a0In that case, it’s a fully fledged “Turn by Turn Navigation System in a Chip”, not a mere chip.<\/p>\n

    If so, it could be a highly disruptive product and needs to be marketed aggressively.<\/p>\n

    From my IITB alumni circles, I was able to informally gather the following clarifications.<\/p>\n