AngularJS - Function Expected or Object is not a Function

New to AngularJS and I guess I don't understand how to call one Promise method from another with the same factory. Every time my code gets to the $http.get within processPerson, I get a Function Expected error in IE, or an Object is not a Function error in Chrome. I've tried reorganizing code many times, multiple factories, etc, and generally get the same error. The only time I can get this to work is if I combine the functions where the processPerson function is embedded within the success of the getPersonnel.

Code:

(function(){

var app = angular.module('hrSite', ['personnel']);

app.controller('PersonnelController', function($scope, personnelFactory){
    var personnelPromise = personnelFactory.getPersonnel();
    personnelPromise.then(function(personnel){
        var perDefs = new Array();
        $.each(personnel.data.value, function( i, person ){
            var perDef = personnelFactory.processPerson(person);
            perDefs.push(perDef);
        });
        $q.all(perDefs).then(function(){
            $scope.personnel = personnel.data.value;
        });
    });
});

})();

(function(){

var personnelModule = angular.module('personnel', []);

personnelModule.factory('personnelFactory', function($http, $q) {

        var getPersonnel = function(){
            return $http.get("/sites/Development/_api/web/lists/getbytitle('Personnel')/items");
        };

        var processPerson = function(person){
            var deferred = $q.defer();
                $http.get("/sites/Development/_api/web/lists/getbytitle('Personnel Skills')/items?$select=*,Skill/Id,Skill/Title&$filter=PersonId eq '"+person.Id+"'&$expand=Skill").then(function(skills){
                    person.Skills = skills.data.value;
                    person.SkillsId = [];
                    $.each(skills.data.value, function( j, skill ){
                        person.SkillsId.push(skill.Id);
                    });
                    deferred.resolve();
                });
            return deferred.promise();
        };
        return {getPersonnel: getPersonnel,
                processPerson: processPerson}
});
})();