How can I use HTML5 geolocation in angularjs

You can use ngGeolocation. It is simple and does the job.

angular.module('appName', ['ngGeolocation'])
    .controller('appCtrl', function($scope, $geolocation) {
         $geolocation.getCurrentPosition().then(function(position) {
            console.log(position, 'current position');
         });
    });

I'd suggest abstracting this into a service so your controller doesn't have a dependency on window.navigator, and to avoid the unnecessary use of $scope.$apply(). Here's what I'm using in my project:

angular.module('app', []).factory('geolocationSvc', ['$q', '$window', function ($q, $window) {

    'use strict';

    function getCurrentPosition() {
        var deferred = $q.defer();

        if (!$window.navigator.geolocation) {
            deferred.reject('Geolocation not supported.');
        } else {
            $window.navigator.geolocation.getCurrentPosition(
                function (position) {
                    deferred.resolve(position);
                },
                function (err) {
                    deferred.reject(err);
                });
        }

        return deferred.promise;
    }

    return {
        getCurrentPosition: getCurrentPosition
    };
}]);

Then I consume it in my controller like this:

function captureUserLocation() {
    geolocationSvc.getCurrentPosition().then(onUserLocationFound);
}

you can do something

myApp.controller('fooCtrl', function($scope){
  if (navigator.geolocation) {
    navigator.geolocation.getCurrentPosition(function(position){
      $scope.$apply(function(){
        $scope.position = position;
      });
    });
  }
})

you need to do $scope.$apply to trigger the digest cycle when the geolocation arrives and to update all the watchers.